Category Archives: 3D Printers

printers

What is Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF) ?

Fused Deposition Modeling (FDM) is an additive manufacturing technology commonly used for modeling, prototyping, and production applications.

FDM works on an “additive” principle by laying down material in layers; a plastic filament or metal wire is unwound from a coil and supplies material to produce a part.

The technology was developed by S. Scott Crump in the late 1980s and was commercialized in 1990.[1]

The term fused deposition modeling and its abbreviation to FDM are trademarked by Stratasys Inc. The exactly equivalent term, fused filament fabrication (FFF), was coined by the members of the RepRap project to give a phrase that would be legally unconstrained in its use.

Process

FDM begins with a software process which processes an STL file (stereolithography file format), mathematically slicing and orienting the model for the build process. If required, support structures may be generated. The machine may dispense multiple materials to achieve different goals: For example, one material may build up the model and another may be used as a soluble support structure.[2] For another example, multiple colors of the same type of thermoplastic may be laid down on the same model.

The thermoplastics are heated past their glass transition temperature and are then deposited by an extrusion head, which follows a tool-path defined by CAM software, and the part is built from the bottom up, one layer at a time. A plastic filament or metal wire is unwound from a coil and supplies material to an extrusion nozzle which can turn the flow on and off. The nozzle is heated to melt the material and can be moved in both horizontal and vertical directions by a numerically controlled mechanism, directly controlled by a computer-aided manufacturing (CAM) software package. The model or part is produced by extruding small beads of thermoplastic material to form layers as the material hardens immediately after extrusion from the nozzle. Stepper motors or servo motors are typically employed to move the extrusion head.

Although as a printing technology FDM is very flexible, and it is capable of dealing with small overhangs by the support from lower layers, FDM generally has some restrictions on the slope of the overhang.

Myriad materials are available, such as ABSPLA, polycarbonate, polyamides, polystyrene, lignin, among many others, with different trade-offs between strength and temperature properties.

Commercial applications

FDM, a prominent form of rapid prototyping, is used for prototyping and rapid manufacturing. Rapid prototyping facilitates iterative testing, and for very short runs, rapid manufacturing can be a relatively inexpensive alternative.[3]

FDM uses the thermoplastics ABS, ABSi, polyphenylsulfone (PPSF), polycarbonate (PC), and Ultem 9085, among others. These materials are used for their heat resistance properties. Ultem 9085 also exhibits fire retardancy making it suitable for aerospace and aviation applications.

FDM is also used in prototyping scaffolds for medical tissue engineering applications.[4]

Maker Faire Rome, Big Numbers and Big News from Rome

Big Numbers and Big News from Rome

BY  ON  · EUROPE,EVENTSINDUSTRY INSIGHTSREVIEW 1 COMMENT

Maker Faire The European Edition Rome

Corrado Doggi is Managing Director of Irish based start-up Creo 3D Printers and he attended the Maker Faire Rome event this past weekend. His dispatch from the heart of Italy, is here for 3DPI’s readers …

Rome has possibly never looked as beautiful as it did last week when I landed, since the glorious days of the Roman Empire, thanks to all the work done in recent years. The size of the Colosseum, the Pantheon and  Vittoriano are intimidating — as were the numbers relating  to “Maker Faire – The European Edition”, which the mother of all cities hosted from the 3rd to the 6th of October at the “Palazzo dei Congressi” 

Maker Faire The European Edition Rome Hall

Quin Etnyre QTechKnowAcross 8000 square metres of exhibition space, which provided a temporary home to more than 200 exhibitors, who were demonstrating many different “make” activities to 20,000 visitors, Maker Faire Rome exceeded all expectations. Individuals and companies were present, with company CEOs as young as 12 years old — I kid you not — personified by Quin Etnyre who founded his company QTechKnow last year at the age of 11 to promote his ArduSensors. He’s also a regular on the hackerspace tutorial circuit. 

Thursday, at the opening conference, the big news that had previously been hinted at by Massimo Banzi, the father of Arduino, at the World Maker Faire in New York last month was revealed in full. After an outstanding introduction by Dale Dougherty, the founder of Maker Faire, Massimo together with Brian Krzanich, CEO of Intel,  announced the collaboration between the two organizations on the development on the new Galileo board. A huge step from a “Big Player” toward the Makers community.

In terms of 3D printing activity — I heard a lot of talk about the acquisition of Makerbot by Stratasys, again a big player spending unbelievable money by any economists calculations…. 450 million! The reactions to the deal tended to be mixed, with some keen to see where MakerBot would go with major backers while others felt betrayed by the corporate sell out.

Ultimaker was present at the faire and it was great to see their  newborn “Ultimaker  2“ featuring a neater look with upgraded solutions that includes much faster but quieter printing. Not that it was easy to tell with the noisy crowds.

CRP, the Italian-based 3D printing materials  and service company was there and presented its electric 3D printed racing bike — this attracted lot of attention from the crowd. Me included.

electric 3D printed racing bike

The Rome event was also the launch pad for the FilaMaker device for easy recycling of 3D printing filament material. Designed by Marek Senický, who had a fully working prototype on show at the event, the FilaMaker produces 3 mm filament which has been tested, and successfully proven, on an Ultimaker 3D printer. Marek is hoping to have a first batch production ready by the end of the year, if all goes well, and sell the Filamaker for around €500.

Robots were also prominent at Maker Faire Rome, as you can see from these pictures I took:

The sheer number of  visitors was unbelievable, considering everyone  had to queue  under the rainy Saturday sky to get into the Faire, you could really feel the excitement in the air when people were seeing and touching 3D printers or 3D printed objects for the first time ever.

The event gave the overall feeling of huge things to come in the 3D printing world, with untold development over the next few years. Everyday people are starting to notice what’s going on and taking an interest. No doubt… this really is the future.

As an entrepreneur in this field, being there for the announcement by Massimo Banzi and Intel was a serious “wow” moment for me. It felt like the beginning of the snowball effect for a movement that’s beginning to gather real momentum.

3D Printing in the Classroom

Interview with Dana Foster: 3D Printing In Education

3D Printing in education is going to be one of the key catalysts to renewing manufacturing in The West. It is literally that important. Something that even politicians are beginning to realise. With this in mind, upon hearing that Dana Foster, Marketer for rp+m and 3D printing evangelist had recent experiences with 3D printing in the classroom, an interview seemed like an opportunity for an educational experience in itself.

3DPI: Hi Dana. As a 3D Printing Marketer you also have experience with children and 3D printing in the classroom. What age group were you talking to?

As a volunteer of Junior Achievement, I was selected to teach a 3rd grade classroom once a week for five consecutive weeks. I had the opportunity to not only teach 3rd grade students about business concepts, but I also introduced my company to them so they could learn about manufacturing and 3D printing.  I have also had several opportunities to attend high school and middle school classes with one of rp+m’s engineers to help introduce 3D printing and how the information they are learning in the classroom can be applied.

3D Prining in Education

3DPI: Children in industrialised countries gain lucidity with technology very quickly in this digitally saturated days: was there a thirst for the technology?

Students were absolutely engaged in our discussions.  The 3rd graders wanted to know if different objects in the classroom were made using our technology (injection moulding and 3D printing).  As for the high school and middle school students, they wanted to use their design software more, so they could print their own parts.  According to the teachers, students were coming into school early, staying late and asking to come into the classroom during their study halls.  The teachers said this never happens! 

3DPI: How did you communicate the way additive processes work?

For the 3rd graders, I described the process as you can create your own 3D model on a computer, such as an iPhone cover (Yes- 3rd graders know everything about iPhones, iPads, etc), send the file to the magnificent 3D printers and the 3D Printer will read the file and start printing your part.  There were a lot of questions if it’s similar to a computer printer and I would answer “Yes, very similar, however instead of 2D, the part comes out as an iPhone cover, so you can touch and feel it. 

3DPI: Was there an onus upon particular types of 3D printing such as FDM or SLS?

I would not say there was an onus, however, when we brought in parts to show or the actual 3D printers themselves (middle school and high school classes), they were FDM and Objet.  At the time, those were the two 3D printing processes we had in-house. Although, now we have also expanded into metal machines — but these are not so easily transportable. 

3DPI: Did you have props such as 3D printed items, or a 3D printer itself?

Yes.  For the 3rd graders, I brought in various parts they would recognize, such as a toilet, that we 3D printed. For the middle school and high school classes, we (Patrick Gannon and myself) brought in a Stratasys uPrint 3D printer and would leave it in the classrooms for a week or two. Specifically for the high school class, we had an iPod case design contest between all of the students and the winners were able to print their design on the uPrint.

All of the designs were very creative, so we decided to leave the uPrint in the classroom for a couple of weeks to print all of the designs.  This is when the students would come into school early to see their design being printed, stay late, or ask to come into the classroom to see the printer working instead of going to Study Hall. 

3DPI: What sort of questions were the students asking?

As stated above, the 3rd graders started asking questions if we made certain parts, such as trashcans, tables, chairs, and more items located in the classroom.  My favorite question was, “Do you make the plastic bags that my mom puts my peanut butter and jelly sandwich in for lunch?”  I tried to hide my laughter, however, thought it was a great question!  You could see the engagement in the students and they were only 8 or 9 years old!  When I was growing up, we never talked about how things were made, such as trashcans, tables, chairs, etc.  In my opinion, these kids will look at manufacturing as an attractive career choice if we include manufacturing education and software into the curriculums.

3DPI: What recommendations would you make to teachers and others in explaining 3D printing to kids?

My recommendation I would make to teachers and others in explaining 3D printing to kids is to first fully understand why 3D printing is so amazing.  Once this is complete, you should explain it in a way the kids will be able to understand.  Relate it to their lives.  Show examples of parts they will understand that can be made on 3D printers.  Videos help tremendously too!  If you do not have access to a 3D printer, do not hesitate to contact me or others around you to figure out a way to see it live in action.  My final recommendation is when explaining the process show your passion while doing it.  Kids pick up on those kinds of things, so if they see you are passionate and excited about 3D printing and manufacturing they will be that bit more interested in the process!

3D Printer Calibration, General procedures

by: RepRapWiki

Calibration is the collection of mechanical “tweaking” processes needed to get exact, quality prints. While your reprap machine may be working as far as the electronics are concerned, calibration is necessary to have well printed parts.

Without calibration, prints may not be the correct dimensions, they may not stick to the build surface, and a variety of other not-so-wanted effects can occur. A Reprap can be calibrated to be as accurate as the mechanics allow.

Once you have finished the physical build of your reprap printer Calibration is the next big hurdle. Trying to print before calibration will likely result in a messy “blob” smeared over the printer bed.

The following set of objects and notes are taken (and edited) from Coasterman who posted them to Thingiverse. They have been moved to the RepRap wiki so that they could more easily be edited and contributed to by the broader community.

The specific recommendation made in this article are based on Skeinforge (or sfact). This information should be nearly equivalent for many other softwares. Regardless of the software used, the set of calibration objects is invaluable.

Note that calibration is an ongoing process that needs to be performed throughout the life of the printer. There are almost always adjustments and tweaks that can be done to improve print quality.

Contents

PAY ATTENTION TO THIS

Whilst calibration is a somewhat iterative process; the order of calibration laid out below is quite important.

It is PARTICULARLY IMPORTANT that the calibration of the motors is done first as poorly calibrated motors can destroy a Pololus and potentially the motors!

Prerequisites

Before attempting calibration, a few things are necessary:

  • A stable build process should be established. Your machine should be completely built and all of the nuts and bolts tightened down.
  • The machine should be on a steady, flat, level surface.
  • Calipers, a level, and any necessary wrenches/screwdrivers to adjust the machine should be handy.

 

Calibration processes

Motor Calibration

Objective: set the current for the stepper motors to the correct level.

Your motors should be quiet when running and can occasionally make musical sounds, particularly when making circles. If they are making a fair amount of noise then you have a problem.

Calibration Object: None

NOTE: incorrect current settings can damage your pololus and/or your motors.

Symptoms

Motors make significant noise.

This generally means you have too much current.

Motor vibrates without turning.

This generally means that you don’t have sufficient current to the motors. You could also have a problem with a part sticking which stops the motor from being able to drive the axis. It might also be possible to be way off in your steps/mm (eg typo), when steps/mm is double the correct value your motor might vibrate on the spot.

Axis movement pauses momentarily and then resumes.

You may have too much current going to the motor which is causing the pololu to over-heat. Reduce the current. This can also be caused by firmware but check your motors first. Another possible cause is the set screw on the gear is not tight enough.

Instructions

Each Pololu has a trimpot located next to the heatsink. The trimpot controls the current that is sent to each motor. Turning the trimpot counter-clockwise reduces the current to the motor, turning it clockwise increases the current to the motor.

Start by adjusting the trimpot down until your motor vibrates on the spot rather than turning cleanly. Now turn the trimpot in a clockwise direction in small increments (1 eighth of a turn) until the motors just start running. Then give the trim port a final turn of about 1 eighth of a turn and your should be good to go.

 

Bed Leveling

Objective: To level the print bed so that your objects will adhere to the surface. The result of this step should make the extruder nozzle the exact same height above the bed across the entire bed surface.

Signs of having an unlevel bed: Plastic will adhere to part of the bed but not others. The extruder nozzle might “dig” into parts of the bed, pulling up or deforming the bed surface.

Importance: The first layer of the print is the foundation of all subsequent layers. Having bad first layers could mean the part might peel off of the print bed during the print, “blobs” of plastic may form, causing problems in following layers, and a variety of other things.

Calibration Object: bedleveling.stl

Instructions

Step 1 – Establish a corner height:

  • Move the nozzle to a corner of the bed and measure its height at this point.
  • Move the nozzle down close to the bed.
  • Use a thick piece of paper or plastic as a shim and slide it under the nozzle. You should feel a slight drag from the extruder on the paper as you pull the paper through. If not, move your nozzle up or down slightly until it does.

Step 2 – Getting the second corner:

  • Move the Y axis (the bed should move) to the second corner.
  • Using the same shim, determine if the bed is too close or too far away from the nozzle at that point.
  • Adjust the screws that hold up the bed along that edge so that the height at the corner matches your shim.
  • Move back to the first corner and check the height with the shim again. It should match, if not, repeat step 1 and step 2 until it does.

Step 3 – Getting the third and fourth corners:

  • There are two ways to adjust this – tweaking the jack screws that hold up your X axis rails and adjusting the bed itself.
    • Jack screw method:
      • Move the Y axis to the third corner and check it with the shim. If it is too high or too low, turn off the motors and slightly rotate one of the jack screws until the nozzle height matches the shim.
      • If this method is used, you MUST return to the second corner and move the nozzle up/down to the shim, and then repeat this method until both sides line up with the shim.
    • Nut and bolt method:
      • Move the Y axis to the third corner and check it with the shim. If it is too high or too low, adjust the bed screws along that edge until they line up.
      • Check the height with the second corner and repeat this method until the corners line up

Once the bed is level print the Bed Leveling Calibration test object and ensure that each square is even, smooth and consistent.

Other methods do exist. Reference Leveling the Print Bed for more information. You may want to download the original scad file so that you can change the dimensions to match your print bed.

Bed surface preparation

Objective: correct preparation of the bed to ensure that objects adhere to it.

Instructions

An incorrectly prepared bed can result in poor adherence of the plastic to the base as well as a ‘bubbling’ effect.

Even a little bit of finger print grease on some surfaces is enough to ruin a print.

Bed preparation will depend on what material your bed is made out of, what you intend on covering it with, as well as what material you expect to be printing:

Glass

Clean the glass with a non-abrasive common household window cleaner (or some would recommend acetone/cheap nail polish) and a lint free cloth. Spare no effort in ensuring that the glass is spotless. With a heated bed and ABS you will probably want something to help the print stick to the bed. Options include: 1. Sugar water (Sugar dissolved in Water approx 1:10 by weight) -> bed temp approx 95 2. ABS juice (ABS dissolved in acetone, eg 10mm length of 3mm filament (0.07g) dissolved in 10ml acetone) -> bed temp approx 90 3. Kapton tape (as below)

Tapes

When applying any type of tape to print on, it is important to make sure the print surface is still smooth when you are done. Attempt to lay down tape edge-to-edge, with no overlap. If applying multiple layers, it can be benificial for the layers to alternate directions, so that direction-specific defects do not build up as you add layers.

Blue Tape

For those printing PLA, blue tape has been found to adhere well to 3M’s ‘Scotch-Blue Painters Tape for Multi-Surfaces #2090’. This tape may be found in two inch rolls, or three inch rolls. The PLA will adhere to multiple layers, so it is advised to place down at least three layers of tape, before printing on a surface, to prevent damage to the print bed.

Kapton Tape

Kapton tape is a heat resistant tape which is commonly used to cover a variety of material types used in beds. The kapton tape provides good adherence for a variety of plastics. It is important to avoid bubbles while applying the tape. The “wet method” is particularly helpful as explained in this video.

Other Materials

TODO: need details on other materials.

Extrusion

Objective: to ensure the hot end temperature is set correctly so that material is extruded cleanly

Calibration Object: None

Extruder steps

Objective: to adjust the extruder steps per unit

Calibration Object: http://www.thingiverse.com/thing:119306

Printer: Prusa i3

PLA, Bad result at 530 steps: http://thingiverse-production.s3.amazonaws.com/assets/4e/a4/3b/8c/ae/DSC_3744_bad.JPG

PLA, Good result at 670 steps: http://thingiverse-production.s3.amazonaws.com/assets/7f/b3/f0/16/f0/DSC_3745_good.JPG

Maybe others can add there results here

PLA

Layer height

Objective: to correct the layer height settings to reflect your printer’s actual layer height.

Calibration Object: 0.5mm-thin-wall.stl

Instructions

Print the 0.5mm thin wall cube and make sure that the layers adhere well but the nozzle does NOT drag through while printing.

Adjust softwares layer height in .01 increments until you get a nice print. In Pronterface/Skeinforge settings, this can be found under Craft > Carve.

Depending on other factors you may find it hard to get all four walls to print nicely. For the first pass if you can get just one wall looking good then move on to the next test.

Infill

Objective: to correct the infill setting.

Calibration Object: 20mm-box.stl

Instructions

Set infill solidity to 1.0 for this. In Pronterface/Skeinforge settings, this can be found under Craft > Fill.

QUESTION: Now that Slic3r is recommended/integrated,

Which is the correct infill option between:

Rectilinear, Line, HoneyComb, Hibertcurves(slow), Archimedeanchords (slow), Octagramspiral (slow)
Print the cube and analyze the top. If there is NOT ENOUGH plastic (a concave top), reduce the Infill Width over Thickness by .05 increments. If there is TOO MUCH plastic (convex top), turn that parameter up by .05 increments. In Pronterface/Skeinforge settings, this can be found either in Craft > Inset in some versions, or Craft > Fill in other versions.

Once you’re feeling close, start bumping it around in smaller increments.

You may also need to adjust your feed rate.

Adjust the feed rate by increments of 2 or so until you feel close. If it looks really disgusting and blobby, go by increments of 0.5mm. Then go by smaller and smaller increments until you’ve nailed it. Although you probably just want to decrease Infill Width over Thickness instead of decreasing Feedrate because lowering feedrate will degrade the resolution.

Temperature control

Objective: to set the hot end temperature correct for your preferred plastic.

Note: you will find that different types of plastic have vastly different temperatures for both your hotend and your bed. What you might not expect is that different colours for the same material can also required different printing temperatures.

As the tower has quite a small ‘top’ surface area you may need to cool this object as you print. If your printer doesn’t have a built in fan you can use any room fan as a substitute.

Calibration Object: 50mm-tower.stl

Instructions

Set the ‘Infill solidity’ to 1.0. In Pronterface/Skeinforge settings, this can be found under Craft > Fill.

If the plastic comes out as a drip instead of a cylindrical filament, the temperature is too high. — http://wiki.ultimaker.com/Troubleshooting#Plastic_comes_out_of_extruder_head_in_a_flowing_state

Start by doing a simple extruder test to determine what the range of temperatures are that you can extrude at. Reduce the temperature in 5 degree increments until the extruder starts skipping when you do a manual extrude. Turn the extruder up 5 degrees and note this as your minimum extruder temperature.

Print this block.

If it looks like a blob, turn down all the temps by 5 degrees until you get something good. Chances are you won’t need to do this more than 5 degrees.

Note: Be careful as going too low can result in the plastic setting making it hard for the motors to drive the plastic, possibly causing wear or damage.

TODO: list temperature ranges for common plastics.

Recommendations

PLA

Hotend: 185 °C Bed: 60 °C

ABS Hotend: 230 °C

Bed: 110 °C

Perimeter Width

Objective: correct the perimeter width over thickness. In newer versions Edge Width over Height.

Calibration Object: perimeter-wt.stl

Instructions

This test prints two objects which are designed to fit together.

Try to insert the smaller block into the larger block. Try inserting it differently a few times, and check your belt tensions.

TODO: Need notes on calibration of belt tensions
If you can get it in a few mm, good. If you can get it in all the way, awesome. The fit should be snug. If it is loose and can jitter around inside, decrease the perimeter width over thickness, also called Edge Width over Height. In Pronterface/Skeinforge, “Edge Width over Height” can be found in Craft > Carve in the Slicing Settings. If you CANNOT get it in AT ALL, and you are sure there are no whiskers blocking it, INCREASE perimeter width over thickness or Edge Width over Height. The latter is more likely.

Bridging

Objective: to maximize your printers ability to bridge gaps (i.e. print in thin air).

Calibration Object: 20mm-hollow-box.stl

Instructions

Print the calibration object and if the top droops in, increase the BRIDGE FEEDRATE MULTIPLIER in Speed by increments of .1 until the top stops drooping.

Print Precision

Objective: improve print precision

Calibration Object: precision-block.stl

Instructions

Then there is the precision block. No real huge calibration parameter here. Just play with this and see how well it does on the overhangs and shapes.

TODO: We need to add some recommendations on how to improve this or find more direct methods of calibrating specific aspects of the print.

Overhang

Objective: fix overhang problems

Calibration Object: overhang-test.stl

 

Instructions

Then there is a simple overhang test. Print and observe the overhangs. This is up to you to figure how to improve the overhangs.

TODO: We need to add some recommendations on how to improve this or find more direct methods of calibrating specific aspects of the print.

gregor: i get better results when i add a fan to cool the overhang down

this was my test object: [1]

Oozebane

Objective: stop material oozing out of the noozle during ‘non-printing’ moves.

Many extruders will emit (ooze) plastic even when the extruder motor is not turning. To overcome this your slicing software needs to ‘retract’ the print medium during head movement when not printing. The retraction creates negative pressure within the hot end heating chamber which effectively sucks the print medium back up through the nozzle, stopping it from oozing.

Calibration Object: oozebane-test.stl

The calibration object prints two towers about 30 mm apart. The head must move between each of the towers at each layer. If your printer is not set correctly then you will see many fine filaments (or strings) between the two towers. You can eliminate these filaments by eliminating ooze.

Calibration Object 2 (Variable sized towers for testing ooze): variable_size_ooze_test_nobase.stl

This is a simple model to help tune reversal parameters for a stepper extruder (using much less filament before actually testing the ooziness). It consists of a number of towers with different thicknesses, with different spacing between each tower. A well-tuned bot should be able to produce even the smallest towers.
Symptoms

Instructions

This is to try to control ooze and calibrate it to be useful.

Start by setting the Early Shutdown distance to 0 and Slowdown Startup Steps to 1.

Print the piece and measure the length of stringers where the extruder shut off and the line is thick before becoming a thin whisker. Take that length and put it into early shutdown distance.

Play with Early Startup Distance Constant until the place where the extruder arrives at the other tower is nice and smooth, so that there isn’t any empty space where plastic should be, but there isn’t excess plastic extruded.

References: http://reprap.org/wiki/Sfact#Q:____What_happened_to_the_old_retraction_settings.3F__What_the_hell_is_oozerate.3F
Since Slic3r 0.9.10b there is a wipe before retract option (under Printer Settings => Extruder) which seems to make the most difference. Other options to consider: reduce temperature, increase travel speed, retracting more, retract slower, z-lift before travel or lowering extrusion ratios.

Overhangs

Objective: eliminate droop from overhangs.

Calibration Object: BridgeTestPart.stl

Instructions

If the calibration object droops, you likely need to decrease “Bridge Flowrate over Operating Flowrate.” Or increase “Bridge Feedrate over Operating Feedrate.”

X & Y scaling and steps/mm calculations

The following information concerning steps/mm adjustments is outdated. It has since been agreed that steps/mm should be set to the exact calculated values since printing with non-ideal steps/mm results in an accurate test piece, but makes the dimensions on every other part even more inaccurate.

Scaling goes into the STEPS_PER_MM of the firmware, track offset goes into the G-code compiler (Skeinforge etc.).

tl;dr

The most simple way to get reasonably accurate parts is to simply ignore the track offset or to set it to some guessed value, then adjust scaling of the axes, only:

<math>\frac {\mbox {current steps per mm} \cdot \mbox {expected distance movement}} \mbox{actual measured distance}</math>

E. g:

 (41.8*100)/94.94=~44.02780703602275121129

Then repeat:

 (44.0278*100)/99.95=~44.04982491245622811406

Until you get your desired steps per mm.

(Do note that there is a setting in configuration.h that enable these EEPROM functions.)

 M501 (show current settings (steps per mm etc)
 M92 X44.04982491245622811406 (change steps per mm to your calculated value, useful for any axis; X,Y,Z and E for Extruder)
 M500 (save your new settings)
  • In Teacup firmware you multiply these values by 1000, to get steps per meter, and put the value left of the decimal into config.h’s STEPS_PER_M_X, STEPS_PER_M_Y, … . Then, re-upload the firmware.

Track Offset

OK, here we get a bit stuck. While the theory section below nicely shows how to calculate the optimum track offset, Skeinforge has no configuration option to adjust this value.

An excerpt from a chat between Greg Frost and Traumflug, on 2011/22/06:
[14:30] <GregFrost_> I calibrated the extruded length and then set feed=flow and pw/t and iw/t to 1.5 and immediately got nice looking prints. However, and here is the kicker, the objects are all slightly too big because my single wall box has an actual w/t of 2.1
[14:31] <GregFrost_> I can fix this with p flow but then i get thin preimeters and they dont alway bond well to each other (but objects are the right size).
[14:31] <GregFrost_> I would like normal flow on the perim but a wider w/t but if i do that it adjusts all of the flows up and I get far too much plastic.
[14:32] <GregFrost_> what I really need is a way to change the distance inside the objest that the perimeter is traced without changing the flow rates.
[14:37] <Traumflug> To be honest, I never used Skeinforge, this adjustable track offset is an assumption.
[14:38] <GregFrost_> Traumflug: it would be a good setting, i agree.
[14:38] <GregFrost_> Traumflug: I think the only way to achieve a track offset is to adjust the perimiter w/t ratio.
[14:38] <Traumflug> So, Skeinforge doesn’t compensate for track width?
[14:38] <GregFrost_> Traumflug: it does. but it uses the perimiter witdth/t and infill w.t settings
[14:39] <GregFrost_> Traumflug: then it uses the layer height
[14:39] <GregFrost_> Traumflug: and useing those it works out the track offset.
[14:39] <Traumflug> ok, good to know.
[14:39] <GregFrost_> Traumflug: but the kicker is, changing perimeter w/t also adjusts the flow rate
[14:40] <GregFrost_> Traumflug: so theoretically when you choose a new w/t, it puts out enuf plastic to fill the width.
[14:40] <Traumflug> Yes, theoretically
[14:41] <GregFrost_> Traumflug: but on the perimiter if you use the same volumetric flow as the infill, it bulges past the desired width because there is no containing line.
[14:42] <GregFrost_> but the one setting that allows you to compensate for that adjusts the flow on all other lines (both infill and permiiters)
[14:42] <Traumflug> IMHO, changing the plastic flow to compensate for size errors isn’t a good way.
[14:43] <GregFrost_> Traumflug: I agree completely.
[14:43] <Traumflug> Each time you change the flow, a lot of minor parameters change as well, so a prediction is very difficult.
[14:43] <GregFrost_> I want to change the track offset.

Theory and Maths

By Markus “Traumflug” Hitter.

X and Y Axis

Both horizontal axes can be calibrated with two values: track offset and overall scaling. To find out how this is done, let’s have a look at a part specially designed to find out those values:

RepRap Calibration Frame Drawing.png

It’s a frame, similar to the one you use to put pictures up onto the wall. The essential part here is, it has long and short distances to measure on the same part. We need to measure both, to distinguish between track offset and scaling.

To the right of the drawing, a few tracks laid down by the extruder are sketched in. It shows how the track offset lets the extruder move closer to the inside of the part, so the outer side of the track just ends where the part should end as well.

All the sizes are overlaid by scaling, which is sort of a “gear ratio” between measurement units and stepper motor steps.

Calibration Object

OpenSCAD

// X-Y Calibration object
// See http://reprap.org/wiki/Calibration#Theory_and_Maths

difference() {
	cube([100,100,3], true);
	cube([80,80,3.1], true);
}

STL file

File:XYCalibration.stl

Basic Equation

With that knowledge, we can sum up what the extruder moves to get the size T = 10 mm exactly 10 mm wide:

<math>\begin{align}

\mbox{movement} = ( \mbox{intended size} – 2 * \mbox{track offset} ) * \mbox{scaling} \\ \end{align}</math>

This holds true for measurements of any size, i.e. also for the 100 mm size of our calibration frame:

<math>\begin{align}

M_{10} & = ( 10\,\mbox{mm} – 2 * TF ) * S \\ M_{100} & = ( 100\,\mbox{mm} – 2 * TF ) * S \\ \end{align}</math>

You see? Two unknowns and two equations, so the set is solvable.

Extending to Erroneous Movements

Now, the whole point of this writing is, the extruder movement doesn’t match what we need to get accurately sized parts. So we have not only a movement, but also a movement error.

The reason for the movement error is, according to the basic equation, erroneous track offset and/or erroneous scaling.

Get these two into the basic equation, result to the left, reason to the right:

<math>\begin{align}

& \mbox{movement} * \mbox{movement error} = \\ & ( \mbox{intended size} – 2 * \mbox{track offset} * \mbox{track offset error} * \mbox{scaling} * \mbox{scaling error} \\ \end{align}</math>

Again, this holds true for both our measurements:

<math>\begin{align}

M_{10} * E_{M10} & = ( 10\,\mbox{mm} – 2 * TF * E_{TF} ) * S * E_S \\ M_{100} * E_{M100} & = ( 100\,\mbox{mm} – 2 * TF * E_{TF} ) * S * E_S \\ \end{align}</math>
… to be continued … about a formula to get scaling and track offset from measuring these 10 mm and 100 mm …

Z Axis

On the Z axis, there is no track offset compensation, so calibration is reduced to scaling of part height. Build any part of 50 mm height, let it cool down, measure it. Then adjust your STEPS_PER_MM in your firmware’s config.h to reduce the difference between intended and received part.

As most RepRaps use a threaded rod on the Z axis, the theoretical value, which can be generated from the online calculator, should match reality pretty close. However, there’s also material shrink as the plastics is printed at a higher temperature than room temperature.

ABS and PLA filament for 3D Printing

THE DIFFERENCE BETWEEN ABS AND PLA FOR 3D PRINTING

This entry was posted on January 27, 2013 by Luke Chilson.

You’ve got a 3D Printer, or you’re looking to buy a 3D Printer and each one seems to indicate it prints in either ABS, PLA, or both. So you find yourself wanting to know, what is the difference between ABS and PLA.

 

Some Common Ground

There are many materials that are being explored for 3D Printing, however you will find that the two dominant plastics are ABS and PLA. Both ABS and PLA are known as thermoplastics; that is they become soft and moldable when heated and return to a solid when cooled. This process can be repeated again and again. Their ability to melt and be processed again is what has made them so prevalent in society and is why most of the plastics you interact with on a daily basis are thermoplastics.

Now while there are many thermoplastics, very few of them are currently used for 3D Printing. For a material to prove viable for 3D Printing, it has to pass three different tests; initial extrusion into Plastic Filament, second extrusion and trace-binding during the 3D Printing process, then finally end use application.

To pass all three tests, a material’s properties must lend desirably to first, it’s formation into the raw 3D Printer feedstock called Plastic Filament; second, process well during 3D Printing giving visually pleasing and physically accurate parts; and lastly, it’s properties should match the intended application, whether that be strength, durability, gloss, you name it. Often, a material will pass one test so superbly, that it becomes worth the extra effort to battle with it during its other stages. Polycarbonate, a lesser known printing material is this way. For some applications, it’s strength and temperature resistance makes it worth the battle to print accurate and fully fused parts.

The first test, that of production from base plastic resin into top-notch Plastic Filament such as what we carry is a strict and carefully monitored process. It is a battle of wits and engineering that takes the plastic from a pile of pellets to a uniformly dense, bubble free, consistently sized, round rod. Here there is little difference between ABS and PLA; most thermoplastics can pass this test, it is mainly just a question of the time and costs required to do so while still producing Plastic Filament that runs smoothly and consistently during the next stage, 3D Printing.

Here is where the two plastics divide and will help to explain why different groups prefer one over the other.

Storage

Both ABS and PLA do best if, before use or when stored long term, they are sealed off from the atmosphere to prevent the absorption of moisture from the air. This does not mean your plastic will be ruined by a week of sitting on a bench in the shop, but long term exposure to a humid environment can have detrimental effects, both to the printing process and to the quality of finished parts.

ABS – Moisture laden ABS will tend to bubble and spurt from the tip of the nozzle when printing; reducing the visual quality of the part, part accuracy, strength and introducing the risk of a stripping or clogging in the nozzle. ABS can be easily dried using a source of hot (preferably dry) air such as a food dehydrator.

PLA – PLA responds somewhat differently to moisture, in addition to bubbles or spurting at the nozzle, you may see discoloration and a reduction in 3D printed part properties as PLA can react with water at high temperatures and undergo de-polymerization. While PLA can also be dried using something as simple as a food dehydrator, it is important to note that this can alter the crystallinity ratio in the PLA and will possibly lead to changes in extrusion temperature and other extrusion characteristics. For many 3D Printers, this need not be of much concern.

Smell

ABS –  While printing ABS, there is often a notable smell of hot plastic. While some complain of the smell, there are many who either do not notice it or do not find it to be particularly unbearable. Ensuring proper ventilation in small rooms, that the ABS used is pure and free of contaminants and heated to the proper temperature in a reliable extruder can go a long way in reducing the smell.

PLA – PLA on the other hand, being derived from sugar gives off a smell similar to a semi-sweet cooking oil. While it certainly won’t bring back fond memories of home-cooked meals, it is considered by many an improvement over hot plastic.

Part Accuracy

Both ABS and PLA are capable of creating dimensionally accurate parts. However, there are a few points worthy of mention regarding the two in this regard.

ABS – For most, the single greatest hurdle for accurate parts in ABS will be a curling upwards of the surface in direct contact with the 3D Printer’s print bed. A combination of heating the print surface and ensuring it is smooth, flat and clean goes a long way in eliminating this issue. Additionally, some find various solutions can be useful when applied beforehand to the print surface. For example, a mixture of ABS/Acetone, or a shot of hairspray.

For fine features on parts involving sharp corners, such as gears, there will often be a slight rounding of the corner. A fan to provide a small amount of active cooling around the nozzle can improve corners but one does also run the risk of introducing too much cooling and reducing adhesion between layers, eventually leading to cracks in the finished part.

PLA – Compared to ABS, PLA demonstrates much less part warping. For this reason it is possible to successfully print without a heated bed and use more commonly available “Blue” painters tape as a print surface. Ironically, totally removing the heated bed can still allow the plastic to curl up slightly on large parts, though not always.

PLA undergoes more of a phase-change when heated and becomes much more liquid. If actively cooled, much sharper details can be seen on printed corners without the risk of cracking or warp. The increased flow can also lead to stronger binding between layers, improving the strength of the printed part.

ABS and PLA General Material Properties

In addition to a part being accurately made, it must also perform in its intended purpose.

ABS – ABS as a polymer can take many forms and can be engineered to have many properties. In general, it is a strong plastic with mild flexibility (compared to PLA). Natural ABS before colorants have been added is a soft milky biege. The flexibility of ABS makes creating interlocking pieces or pin connected pieces easier to work with. It is easily sanded and machined. Notably, ABS is soluble in Acetone allowing one to weld parts together with a drop or two, or smooth and create high gloss by brushing or dipping full pieces in Acetone.

It’s strength, flexibility, machinability, and higher temperature resistance make it often a preferred plastic by engineers and those with mechanical uses in mind.

PLA –  Created from processing any number of plant products including corn, potatoes or sugar-beets, PLA is considered a more ‘earth friendly’ plastic compared to petroleum based ABS. Used primarily in food packaging and containers, PLA can be composted at comercial compost facilities. It won’t bio-degrade in your backyard or home compost pile however. It is natural transparent and can be colored to various degrees of translucency and opacity. Also strong, and more rigid than ABS, it is occasionally more difficult to work with in complicated interlocking assemblies and pin-joints. Printed objects will generally have a glossier look and feel than ABS. With a little more work, PLA can also be sanded and machined. The lower melting temperature of PLA makes it unsuitable for many applications as even parts spending the day in a hot car can droop and deform.

In Summary

Simplifying the myriad factors that influence the use of one material over the other, broad strokes draw this comparison.

ABS – It’s strength, flexibility, machinability, and higher temperature resistance make it often a preferred plastic for engineers, and professional applications. The hot plastic smell deter some as does the plastics petroleum based origin. The additional requirement of a heated print bed means there are some printers simply incapable of printing ABS with any reliability.

PLA – The wide range of available colors and translucencies and glossy feel often attract those who print for display or small household uses. Many appreciate the plant based origins and prefer the semi-sweet smell over ABS. When properly cooled, PLA seems to have higher maximum printing speeds, lower layer heights, and sharper printed corners. Combining this with low warping on parts make it a popular plastic for home printers, hobbyists, and schools.

Industries and Companies ideal for 3D Printing

Industries and Companies ideal for 3D Printing                                         by: 3Sourceful

While mainstream adoption is still many years away, 3D printing is already common in certain niche applications.  The key success drivers to adoption of 3D printing for a particular application are:

Low Quantities – 3D printing technology is typically only economical for low production quantities.  As quantities increase, its higher production costs make it uncompetitive.

High Willingness-to-Pay – Since production and material costs are significantly higher with 3D printing; industries that are extremely cost sensitive are not good candidates for adoption.

High Complexity – Products demanding complex forms help justify the increased cost of 3D printing.  Traditionally, complexity can require multiple production technologies and assembly steps.  As described above, complexity is ‘free’ in 3D printing.

Supply Chain Impact – The unique tooling and setup costs of 3D printing mean that it can be quite disruptive in small niches of the supply chain.  Industries and applications that have high supply chain costs relative to products costs are good candidates for adoption.

Data Availability  – All 3D printers need computer data to operate.  Certain industries and applications have an advantage in having a wealth of data available so that they reduce the content creation barrier to adoption.

The following industries and applications can be broken down along these factors.  Note that most applications require that several factors be favorable for adoption.

Medical Devices –Medical devices have been using 3D printing technology for quite some time.  There are several factors for this.  All custom medical devices have production values of one.  Products are purchased on performance vs. cost.  Complexity is high for prosthetics, etc.  And, the recent advantages in scanning technologies mean that there is a wealth of digital data available.  An example application is Invisalign.  Invisalign 3D prints series of orthodontic correction devices for their customers from their dental scans.

Aerospace – As with many new technologies, aerospace is one of the first major industries to adopt.  Performance requirements are high and production volumes are much lower as compared with consumer devices.  There is also a high willingness-to-pay.  Finally, since programs can last decades, keeping the required spare parts on hand is very difficult and costly.  Examples of applications of 3D printing in aerospace include instrument panels made by RC Allen.  General Electric Aviation recently acquired one of the major metal 3D printing service providers, Morris Technologies.

Niche Markets  – Traditionally, when small companies have ideas for physical products they often cannot execute on their ideas because of the large fixed costs associated with having something produced.  These barriers are now removed.  Kappius components are a great example.  Kappius makes very racing bicycle components for a particular style of competition.  Due to volumes, high customer willingness to pay, and high product complexity, 3D printing was the best technology for production.

Spare Parts – While most businesses try to avoid inventory, inventory is the business in the spare parts industry.  A huge variety of parts have to be held for many years.  Rather than buying and holding, 3D printing could print spare parts on demand.  Volumes are low enough to remain cost competitive.  And customers typical have a very high willingness-to-pay since the parts may well be critical for larger equipment.  NASA has discussed using a 3D printer in space to produce parts when needed.  And newer companies, such as the Swedish music products business Teenage Engineering, are utilizing 3D printing to eliminate that portion of their supply chain.  Teenage Engineering now posts the CAD files for the spare parts for free and will tell users where to have them printed. (3Ders.org)

Mass – Mass Customization – Shapeways is a New York based venture funded company that creates a market for consumer to consumer sales.  Individuals can upload their own designs for anyone to purchase.  Shapeways performs the 3D printing for all designs sorted through their site.  Additionally, Shapeways has solved the ‘CAD data issues’ as users provide the necessary CAD designs.  Shapeways has received $47MM in venture funding to date.  (Tech Crunch)

A summary of these factors applied across industries is below:

3dfactor

 

3D Printing old inventions that have fallen into public domain!

3D printing breathes new life into old inventions

By Jacob Kastrenakes on 

 
3

The US Patent and Trademark Office may be the key battleground in today’s high-tech lawsuits, but it’s also home to a trove of inventions that have fallen into the public domain. Now patent lawyer Martin Galese is trying to bring some 21st century tech to the charming ideas patented in the 19th and 20th centuries. He’s dug up eccentric creations — from anEscher-esque building block to a combination comb and hair clip — and is rebuilding them using digital modeling tools, allowing anyone with a 3D printer to own a once-patented work from the past.

“You’re holding the 19th century by way of something that was produced in the 21st century,” Galese told The New York Times. Galese said that he sees the intricate drawings that accompany many patents as beautiful works of art, but that isn’t the aspect he appreciates most: the real idea of his Patent-Able blog, where all of his 3D models are featured, is to help people see the patent office as as wealth of ideas, and not just the impetus for endless legal battles.

 

MOST PATENTS HAVE FALLEN INTO THE PUBLIC DOMAIN

Galese notes that there are over 8 million registered patents — and according to thePatently-O law blog’s estimates, only about 2.1 million of those were still in force last year. Just over a dozen patents have been featured so far on Galese’s blog, and he’s still on the lookout for “cool, weird, [and] surprisingly useful” ideas from the past to turn into 3D models. He uses MakerBot’s Thingiverse website — which collects and shares user-generated 3D models — to host all of his recreations. Galese thinks that it’s a fitting home for them: the patent office’s archives, he told the Times, are really just the “original Thingiverse.”

 

Tell me what a 3D Scanner is.

3D Scanner
From Wikipedia, the free encyclopedia
3D computer graphics
Glasses 800 edit.png
Basics
Primary Uses
Related concepts

3-D scanning at a Maker Faire

3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance (i.e. color). The collected data can then be used to construct digital, three dimensional models.

Many different technologies can be used to build these 3D scanning devices; each technology comes with its own limitations, advantages and costs. Many limitations in the kind of objects that can be digitized are still present, for example, optical technologies encounter many difficulties with shiny, mirroring or transparent objects.

Collected 3D data is useful for a wide variety of applications. These devices are used extensively by the entertainment industry in the production of movies and video games. Other common applications of this technology include industrial designorthotics and prosthetics,reverse engineering and prototypingquality control/inspection and documentation of cultural artifacts.

Functionality

3D scanning of a fin whale skeleton in the Natural History Museum of Slovenia(August 2013)

The purpose of a 3D scanner is usually to create a point cloud of geometric samples on the surface of the subject. These points can then be used to extrapolate the shape of the subject (a process called reconstruction). If color information is collected at each point, then the colors on the surface of the subject can also be determined.

3D scanners share several traits with cameras. Like cameras, they have a cone-like field of view, and like cameras, they can only collect information about surfaces that are not obscured. While a camera collects color information about surfaces within its field of view, a 3D scanner collects distance information about surfaces within its field of view. The “picture” produced by a 3D scanner describes the distance to a surface at each point in the picture. This allows the three dimensional position of each point in the picture to be identified.

For most situations, a single scan will not produce a complete model of the subject. Multiple scans, even hundreds, from many different directions are usually required to obtain information about all sides of the subject. These scans have to be brought into a commonreference system, a process that is usually called alignment or registration, and then merged to create a complete model. This whole process, going from the single range map to the whole model, is usually known as the 3D scanning pipeline.[1]

Technology

There are a variety of technologies for digitally acquiring the shape of a 3D object. A well established classification[2] divides them into two types: contact and non-contact 3D scanners. Non-contact 3D scanners can be further divided into two main categories, active scanners and passive scanners. There are a variety of technologies that fall under each of these categories.

Contact

A coordinate measuring machine with rigid perpendicular arms.

Contact 3D scanners probe the subject through physical touch, while the object is in contact with or resting on a precision flat surface plate, ground and polished to a specific maximum of surface roughness. Where the object to be scanned is not flat or can not rest stably on a flat surface, it is supported and held firmly in place by a fixture.

The scanner mechanism may have three different forms:

  • A carriage system with rigid arms held tightly in perpendicular relationship and each axis gliding along a track. Such systems work best with flat profile shapes or simple convex curved surfaces.
  • An articulated arm with rigid bones and high precision angular sensors. The location of the end of the arm involves complex math calculating the wrist rotation angle and hinge angle of each joint. This is ideal for probing into crevasses and interior spaces with a small mouth opening.
  • A combination of both methods may be used, such as an articulated arm suspended from a traveling carriage, for mapping large objects with interior cavities or overlapping surfaces.

CMM (coordinate measuring machine) is an example of a contact 3D scanner. It is used mostly in manufacturing and can be very precise. The disadvantage of CMMs though, is that it requires contact with the object being scanned. Thus, the act of scanning the object might modify or damage it. This fact is very significant when scanning delicate or valuable objects such as historical artifacts. The other disadvantage of CMMs is that they are relatively slow compared to the other scanning methods. Physically moving the arm that the probe is mounted on can be very slow and the fastest CMMs can only operate on a few hundred hertz. In contrast, an optical system like a laser scanner can operate from 10 to 500 kHz.

Other examples are the hand driven touch probes used to digitize clay models in computer animation industry.

Non-contact active

Active scanners emit some kind of radiation or light and detect its reflection or radiation passing through object in order to probe an object or environment. Possible types of emissions used include light, ultrasound or x-ray.

Time-of-flight

This lidar scanner may be used to scan buildings, rock formations, etc., to produce a 3D model. The lidar can aim its laser beam in a wide range: its head rotates horizontally, a mirror flips vertically. The laser beam is used to measure the distance to the first object on its path.

The time-of-flight 3D laser scanner is an active scanner that uses laser light to probe the subject. At the heart of this type of scanner is a time-of-flight laser rangefinder. The laser rangefinder finds the distance of a surface by timing the round-trip time of a pulse of light. A laser is used to emit a pulse of light and the amount of time before the reflected light is seen by a detector is measured. Since the speed of light c is known, the round-trip time determines the travel distance of the light, which is twice the distance between the scanner and the surface. If t is the round-trip time, then distance is equal to  \textstyle c \! \cdot  \! t / 2. The accuracy of a time-of-flight 3D laser scanner depends on how precisely we can measure the t time: 3.3 picoseconds (approx.) is the time taken for light to travel 1 millimeter.

The laser rangefinder only detects the distance of one point in its direction of view. Thus, the scanner scans its entire field of view one point at a time by changing the range finder’s direction of view to scan different points. The view direction of the laser rangefinder can be changed either by rotating the range finder itself, or by using a system of rotating mirrors. The latter method is commonly used because mirrors are much lighter and can thus be rotated much faster and with greater accuracy. Typical time-of-flight 3D laser scanners can measure the distance of 10,000~100,000 points every second.

Time-of-flight devices are also available in a 2D configuration. This is referred to as a time-of-flight camera.

Triangulation

Principle of a laser triangulation sensor. Two object positions are shown.

Triangulation based 3D laser scanners are also active scanners that use laser light to probe the environment. With respect to time-of-flight 3D laser scanner the triangulation laser shines a laser on the subject and exploits a camera to look for the location of the laser dot. Depending on how far away the laser strikes a surface, the laser dot appears at different places in the camera’s field of view. This technique is called triangulation because the laser dot, the camera and the laser emitter form a triangle. The length of one side of the triangle, the distance between the camera and the laser emitter is known. The angle of the laser emitter corner is also known. The angle of the camera corner can be determined by looking at the location of the laser dot in the camera’s field of view. These three pieces of information fully determine the shape and size of the triangle and gives the location of the laser dot corner of the triangle. In most cases a laser stripe, instead of a single laser dot, is swept across the object to speed up the acquisition process. The National Research Council of Canada was among the first institutes to develop the triangulation based laser scanning technology in 1978.[3]

Strengths and weaknesses

Time-of-flight and triangulation range finders each have strengths and weaknesses that make them suitable for different situations. The advantage of time-of-flight range finders is that they are capable of operating over very long distances, on the order of kilometers. These scanners are thus suitable for scanning large structures like buildings or geographic features. The disadvantage of time-of-flightrange finders is their accuracy. Due to the high speed of light, timing the round-trip time is difficult and the accuracy of the distance measurement is relatively low, on the order of millimeters.
Triangulation range finders are exactly the opposite. They have a limited range of some meters, but their accuracy is relatively high. The accuracy of triangulation range finders is on the order of tens of micrometers.

Time-of-flight scanners accuracy can be lost when the laser hits the edge of an object because the information that is sent back to the scanner is from two different locations for one laser pulse. The coordinate relative to the scanners position for a point that has hit the edge of an object will be calculated based on an average and therefore will put the point in the wrong place. When using a high resolution scan on an object the chances of the beam hitting an edge are increased and the resulting data will show noise just behind the edges of the object. Scanners with a smaller beam width will help to solve this problem but will be limited by range as the beam width will increase over distance. Software can also help by determining that the first object to be hit by the laser beam should cancel out the second.

At a rate of 10,000 sample points per second, low resolution scans can take less than a second, but high resolution scans, requiring millions of samples, can take minutes for some time-of-flight scanners. The problem this creates is distortion from motion. Since each point is sampled at a different time, any motion in the subject or the scanner will distort the collected data. Thus, it is usually necessary to mount both the subject and the scanner on stable platforms and minimize vibration. Using these scanners to scan objects in motion is very difficult.

Recently, there has been research on compensating for distortion from small amounts of vibration.[4]

When scanning in one position for any length of time slight movement can occur in the scanner position due to changes in temperature. If the scanner is set on a tripod and there is strong sunlight on one side of the scanner then that side of the tripod will expand and slowly distort the scan data from one side to another. Some laser scanners have level compensators built into them to counteract any movement of the scanner during the scan process.

Conoscopic holography

In a conoscopic system, a laser beam is projected onto the surface and then the immediate reflection along the same ray-path are put through a conoscopic crystal and projected onto a CCD. The result is a diffraction pattern, that can be frequency analyzed to determine the distance to the measured surface. The main advantage with conoscopic holography is that only a single ray-path is needed for measuring, thus giving an opportunity to measure for instance the depth of a finely drilled hole.

Hand-held laser scanners

Hand-held laser scanners create a 3D image through the triangulation mechanism described above: a laser dot or line is projected onto an object from a hand-held device and a sensor (typically a charge-coupled device or position sensitive device) measures the distance to the surface. Data is collected in relation to an internal coordinate system and therefore to collect data where the scanner is in motion the position of the scanner must be determined. The position can be determined by the scanner using reference features on the surface being scanned (typically adhesive reflective tabs, but natural features have been also used in research work [5][6]) or by using an external tracking method. External tracking often takes the form of a laser tracker (to provide the sensor position) with integrated camera (to determine the orientation of the scanner) or a photogrammetric solution using 3 or more cameras providing the complete Six degrees of freedom of the scanner. Both techniques tend to use infrared Light-emitting diodes attached to the scanner which are seen by the camera(s) through filters providing resilience to ambient lighting.

Data is collected by a computer and recorded as data points within Three-dimensional space, with processing this can be converted into a triangulated mesh and then a Computer-aided design model, often as Nonuniform rational B-spline surfaces. Hand-held laser scanners can combine this data with passive, visible-light sensors—which capture surface textures and colors—to build (or “reverse engineer“) a full 3D model.

Structured light

Structured-light 3D scanners project a pattern of light on the subject and look at the deformation of the pattern on the subject. The pattern is projected onto the subject using either anLCD projector or other stable light source. A camera, offset slightly from the pattern projector, looks at the shape of the pattern and calculates the distance of every point in the field of view.

Structured-light scanning is still a very active area of research with many research papers published each year. Perfect maps have also been proven useful as structured light patterns that solve the correspondence problem and allow for error detection and error correction.[24] [See Morano, R., et al. “Structured Light Using Pseudorandom Codes,” IEEE Transactions on Pattern Analysis and Machine Intelligence.

The advantage of structured-light 3D scanners is speed and precision. Instead of scanning one point at a time, structured light scanners scan multiple points or the entire field of view at once. Scanning an entire field of view in a fraction of a second generates profiles that are exponentially more precise than laser triangulation. This reduces or eliminates the problem of distortion from motion. Some existing systems are capable of scanning moving objects in real-time. VisionMaster creates a 3D scanning system with a 5-megapixel camera – 5 million data points are acquired in every frame.

A real-time scanner using digital fringe projection and phase-shifting technique (a various structured light method) was developed, to capture, reconstruct, and render high-density details of dynamically deformable objects (such as facial expressions) at 40 frames per second.[7] Recently, another scanner is developed. Different patterns can be applied to this system. The frame rate for capturing and data processing achieves 120 frames per second. It can also scan isolated surfaces, for example two moving hands.[8] By utilizing the binary defocusing technique, speed breakthroughs have been made that could reach hundreds of [9] to thousands of frames per second.[10]

Modulated light

Modulated light 3D scanners shine a continually changing light at the subject. Usually the light source simply cycles its amplitude in a sinusoidal pattern. A camera detects the reflected light and the amount the pattern is shifted by determines the distance the light traveled. Modulated light also allows the scanner to ignore light from sources other than a laser, so there is no interference.

Volumetric techniques

Medical

Computed tomography (CT) is a medical imaging method which generates a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images, similarly Magnetic resonance imaging is another a medical imaging technique that provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular, and oncological (cancer) imaging. These techniques produce a discrete 3D volumetric representation that can be directly visualized, manipulated or converted to traditional 3D surface by mean of isosurface extraction algorithms.

Industrial

Although most common in medicine, Computed tomography, Microtomography and MRI are also used in other fields for acquiring a digital representation of an object and its interior, such as nondestructive materials testing, reverse engineering, or the study biological and paleontological specimens.

Non-contact passive

Passive scanners do not emit any kind of radiation themselves, but instead rely on detecting reflected ambient radiation. Most scanners of this type detect visible light because it is a readily available ambient radiation. Other types of radiation, such as infrared could also be used. Passive methods can be very cheap, because in most cases they do not need particular hardware but simple digital cameras.

  • Stereoscopic systems usually employ two video cameras, slightly apart, looking at the same scene. By analyzing the slight differences between the images seen by each camera, it is possible to determine the distance at each point in the images. This method is based on the same principles driving human stereoscopic vision[1].
  • Photometric systems usually use a single camera, but take multiple images under varying lighting conditions. These techniques attempt to invert the image formation model in order to recover the surface orientation at each pixel.
  • Silhouette techniques use outlines created from a sequence of photographs around a three-dimensional object against a well contrasted background. These silhouettes are extruded and intersected to form the visual hull approximation of the object. With these approaches some concavities of an object (like the interior of a bowl) cannot be detected.

User assisted (image-based modeling)

There are other methods that, based on the user assisted detection and identification of some features and shapes on a set of different pictures of an object are able to build an approximation of the object itself. This kind of techniques are useful to build fast approximation of simple shaped objects like buildings. Various commercial packages are available likeD-SculptoriModellerAutodesk ImageModeler or PhotoModeler.

This sort of 3D scanning is based on the principles of photogrammetry. It is also somewhat similar in methodology to panoramic photography, except that the photos are taken of one object on a three-dimensional space in order to replicate it instead of taking a series of photos from one point in a three-dimensional space in order to replicate the surrounding environment.

Reconstruction

From point clouds

The point clouds produced by 3D scanners can be used directly for measurement and visualization in the architecture and construction world.

Most applications, however, use instead polygonal 3D models, NURBS surface models, or editable feature-based CAD models (aka Solid models).

  • Polygon mesh models: In a polygonal representation of a shape, a curved surface is modeled as many small faceted flat surfaces (think of a sphere modeled as a disco ball). Polygon models—also called Mesh models, are useful for visualization, for some CAM (i.e., machining), but are generally “heavy” ( i.e., very large data sets), and are relatively un-editable in this form. Reconstruction to polygonal model involves finding and connecting adjacent points with straight lines in order to create a continuous surface. Many applications, both free and nonfree, are available for this purpose (e.g. MeshLab, PointCab, kubit PointCloud for AutoCAD, JRC 3D Reconstructor, imagemodel, PolyWorks, Rapidform, Geomagic, Imageware, Rhino 3D etc.).
  • Surface models: The next level of sophistication in modeling involves using a quilt of curved surface patches to model our shape. These might be NURBS, TSplines or other curved representations of curved topology. Using NURBS, our sphere is a true mathematical sphere. Some applications offer patch layout by hand but the best in class offer both automated patch layout and manual layout. These patches have the advantage of being lighter and more manipulable when exported to CAD. Surface models are somewhat editable, but only in a sculptural sense of pushing and pulling to deform the surface. This representation lends itself well to modeling organic and artistic shapes. Providers of surface modelers include Rapidform, GeomagicRhino 3D, Maya, T Splines etc.
  • Solid CAD models: From an engineering/manufacturing perspective, the ultimate representation of a digitized shape is the editable, parametric CAD model. After all, CAD is the common “language” of industry to describe, edit and maintain the shape of the enterprise’s assets. In CAD, our sphere is described by parametric features which are easily edited by changing a value (e.g., centerpoint and radius).

These CAD models describe not simply the envelope or shape of the object, but CAD models also embody the “design intent” (i.e., critical features and their relationship to other features). An example of design intent not evident in the shape alone might be a brake drum’s lug bolts, which must be concentric with the hole in the center of the drum. This knowledge would drive the sequence and method of creating the CAD model; a designer with an awareness of this relationship would not design the lug bolts referenced to the outside diameter, but instead, to the center. A modeler creating a CAD model will want to include both Shape and design intent in the complete CAD model.

Vendors offer different approaches to getting to the parametric CAD model. Some export the NURBS surfaces and leave it to the CAD designer to complete the model in CAD (e.g.,Geomagic, Imageware, Rhino 3D). Others use the scan data to create an editable and verifiable feature based model that is imported into CAD with full feature tree intact, yielding a complete, native CAD model, capturing both shape and design intent (e.g. Geomagic, Rapidform). Still other CAD applications are robust enough to manipulate limited points or polygon models within the CAD environment (e.g., CATIA, AutoCAD, Revit).

From a set of 2D slices

3D reconstruction of the brain and eyeballs from CT scanned DICOM images. In this image, areas with the density of bone or air were made transparent, and the slices stacked up in an approximate free-space alignment. The outer ring of material around the brain are the soft tissues of skin and muscle on the outside of the skull. A black box encloses the slices to provide the black background. Since these are simply 2D images stacked up, when viewed on edge the slices disappear since they have effectively zero thickness. Each DICOM scan represents about 5mm of material averaged into a thin slice.

CTindustrial CTMRI, or Micro-CT scanners do not produce point clouds but a set of 2D slices (each termed a “tomogram”) which are then ‘stacked together’ to produce a 3D representation. There are several ways to do this depending on the output required:

  • Volume rendering: Different parts of an object usually have different threshold values or greyscale densities. From this, a 3-dimensional model can be constructed and displayed on screen. Multiple models can be constructed from various thresholds, allowing different colors to represent each component of the object. Volume rendering is usually only used for visualisation of the scanned object.
  • Image segmentation: Where different structures have similar threshold/greyscale values, it can become impossible to separate them simply by adjusting volume rendering parameters. The solution is called segmentation, a manual or automatic procedure that can remove the unwanted structures from the image. Image segmentation software usually allows export of the segmented structures in CAD or STL format for further manipulation.
  • Image-based meshing: When using 3D image data for computational analysis (e.g. CFD and FEA), simply segmenting the data and meshing from CAD can become time consuming, and virtually intractable for the complex topologies typical of image data. The solution is called image-based meshing, an automated process of generating an accurate and realistic geometrical description of the scan data.

Applications

Material processing and production

Main article: Laser scanning

Laser scanning describes the general method to sample or scan a surface using laser technology. Several areas of application exist that mainly differ in the power of the lasers that are used, and in the results of the scanning process. Low laser power is used when the scanned surface doesn’t have to be influenced, e.g. when it only has to be digitized. Confocal or 3D laser scanning are methods to get information about the scanned surface. Another low-power application are structured light projection systems that are used for solar cell flatness metrology enabling stress calculation with throughout in excess of 2000 wafers per hour.[11]

The laser power used for laser scanning equipment in industrial applications is typically less than 1W. The power level is usually on the order of 200 mW or less.

Construction industry and civil engineering

  • Robotic Control: e.g., a laser scanner may function as the “eye” of a robot.[12][13]
  • As-built drawings of Bridges, Industrial Plants, and Monuments
  • Documentation of historical sites
  • Site modeling and lay outing
  • Quality control
  • Quantity Surveys
  • Freeway Redesign
  • Establishing a bench mark of pre-existing shape/state in order to detect structural changes resulting from exposure to extreme loadings such as earthquake, vessel/truck impact or fire.
  • Create GIS (Geographic information system) maps and Geomatics.
  • Subsurface Laser Scanning in mines and Karst voids.[14]
  • Forensic Documentation [15]

Benefits of 3D scanning

3D model scanning could benefit the design process if:

  • Increase effectiveness working with complex parts and shapes.
  • Help with design of products to accommodate someone else’s part.
  • If CAD models are outdated, a 3D scan will provide an updated version
  • Replacement of missing or older parts

Entertainment

3D scanners are used by the entertainment industry to create digital 3D models for moviesvideo games and leisure purposes. They are heavily utilized in virtual cinematography. In cases where a real-world equivalent of a model exists, it is much faster to scan the real-world object than to manually create a model using 3D modeling software. Frequently, artists sculpt physical models of what they want and scan them into digital form rather than directly creating digital models on a computer.

Reverse engineering

Reverse engineering of a mechanical component requires a precise digital model of the objects to be reproduced. Rather than a set of points a precise digital model can be represented by a polygon mesh, a set of flat or curved NURBS surfaces, or ideally for mechanical components, a CAD solid model. A 3D scanner can be used to digitize free-form or gradually changing shaped components as well as prismatic geometries whereas a coordinate measuring machine is usually used only to determine simple dimensions of a highly prismatic model. These data points are then processed to create a usable digital model, usually using specialized reverse engineering software.

Cultural heritage

There have been many research projects undertaken via the scanning of historical sites and artifacts both for documentation and analysis purposes.

The combined use of 3D scanning and 3D printing technologies allows the replication of real objects without the use of traditional plaster casting techniques, that in many cases can be too invasive for being performed on precious or delicate cultural heritage artifacts.[16] In the side figure the gargoyle model on the left was digitally acquired by using a 3D scanner and the produced 3D data was processed using MeshLab. The resulting digital 3D model was used by a rapid prototyping machine to create a real resin replica of original object.

Michelangelo

In 1999, two different research groups started scanning Michelangelo’s statues. Stanford University with a group led by Marc Levoy[17] used a custom laser triangulation scanner built by Cyberware to scan Michelangelo’s statues in Florence, notably the David, the Prigioni and the four statues in The Medici Chapel. The scans produced a data point density of one sample per 0.25 mm, detailed enough to see Michelangelo’s chisel marks. These detailed scans produced a huge amount of data (up to 32 gigabytes) and processing the data from his scans took 5 months. Approximately in the same period a research group from IBM, led by H. Rushmeier and F. Bernardini scanned the Pietà of Florence acquiring both geometric and color details. The digital model, result of the Stanford scanning campaign, was thoroughly used in the 2004 subsequent restoration of the statue.[18]

Monticello

In 2002, David Luebke, et al. scanned Thomas Jefferson’s Monticello.[19] A commercial time of flight laser scanner, the DeltaSphere 3000, was used. The scanner data was later combined with color data from digital photographs to create the Virtual Monticello, and the Jefferson’s Cabinet exhibits in the New Orleans Museum of Art in 2003. The Virtual Monticello exhibit simulated a window looking into Jefferson’s Library. The exhibit consisted of a rear projection display on a wall and a pair of stereo glasses for the viewer. The glasses, combined with polarized projectors, provided a 3D effect. Position tracking hardware on the glasses allowed the display to adapt as the viewer moves around, creating the illusion that the display is actually a hole in the wall looking into Jefferson’s Library. The Jefferson’s Cabinet exhibit was a barrier stereogram (essentially a non-active hologram that appears different from different angles) of Jefferson’s Cabinet.

Cuneiform tablets

In 2003, Subodh Kumar, et al. undertook the 3D scanning of ancient cuneiform tablets.[20] Again, a laser triangulation scanner was used. The tablets were scanned on a regular grid pattern at a resolution of 0.025 mm (0.00098 in).

Kasubi Tombs

Photo overlaid atop laser scan data from a project held in early 2009 at Uganda’s Kasubi Tombs, which were destroyed by fire in early 2010; the data is slated for use in the building’s reconstruction.

A 2009 CyArk 3D scanning project at Uganda’s historic Kasubi Tombs, a UNESCO World Heritage Site, using a Leica HDS 4500, produced detailed architectural models of Muzibu Azaala Mpanga, the main building at the complex and tomb of the Kabakas (Kings) of Uganda. A fire on March 16, 2010, burned down much of the Muzibu Azaala Mpanga structure, and reconstruction work is likely to lean heavily upon the dataset produced by the 3D scan mission.[21]

“Plastico di Roma antica”

In 2005, Gabriele Guidi, et al. scanned the “Plastico di Roma antica”,[22] a model of Rome created in the last century. Neither the triangulation method, nor the time of flight method satisfied the requirements of this project because the item to be scanned was both large and contained small details. They found though, that a modulated light scanner was able to provide both the ability to scan an object the size of the model and the accuracy that was needed. The modulated light scanner was supplemented by a triangulation scanner which was used to scan some parts of the model.

Other projects

The 3D Encounters Project at the Petrie Museum of Egyptian Archaeology aims to use 3D laser scanning to create a high quality 3D image library of artefacts and enable digital travelling exhibitions of fragile Egyptian artefacts, English Heritage has investigated the use of 3D laser scanning for a wide range of applications to gain archaeological and condition data, and the National Conservation Centre in Liverpool has also produced 3D laser scans on commission, including portable object and in situ scans of archaeological sites.[23]

Medical CAD/CAM

3D scanners are used in order to capture the 3D shape of a patient in orthotics and dentistry. It gradually supplants tedious plaster cast. CAD/CAM software are then used to design and manufacture the orthosisprosthesis or dental implants.

Many Chairside dental CAD/CAM systems and Dental Laboratory CAD/CAM systems use 3D Scanner technologies to capture the 3D surface of a dental preparation (either in vivo orin vitro), in order to produce a restoration digitally using CAD software and ultimately produce the final restoration using a CAM technology (such as a CNC milling machine, or 3D printer). The chairside systems are designed to facilitate the 3D scanning of a preparation in vivo and produce the restoration (such as a Crown, Onlay, Inlay or Veneer).

Quality assurance and industrial metrology

The digitalization of real-world objects is of vital importance in various application domains. This method is especially applied in industrial quality assurance to measure the geometric dimension accuracy. Industrial processes such as assembly are complex, highly automated and typically based on CAD (Computer Aided Design) data. The problem is that the same degree of automation is also required for quality assurance. It is, for example, a very complex task to assemble a modern car, since it consists of many parts that must fit together at the very end of the production line. The optimal performance of this process is guaranteed by quality assurance systems. Especially the geometry of the metal parts must be checked in order to assure that they have the correct dimensions, fit together and finally work reliably.

Within highly automated processes, the resulting geometric measures are transferred to machines that manufacture the desired objects. Due to mechanical uncertainties and abrasions, the result may differ from its digital nominal. In order to automatically capture and evaluate these deviations, the manufactured part must be digitized as well. For this purpose, 3D scanners are applied to generate point samples from the object’s surface which are finally compared against the nominal data.[24]

The process of comparing 3D data against a CAD model is referred to as CAD-Compare, and can be a useful technique for applications such as determining wear patterns on molds and tooling, determining accuracy of final build, analyzing gap and flush, or analyzing highly complex sculpted surfaces. At present, laser triangulation scanners, structured light and contact scanning are the predominant technologies employed for industrial purposes, with contact scanning remaining the slowest, but overall most accurate option.

3D printing Chocolate innovations, Food for thought!?

http://qz.com/77751/3d-printing-chocolate-is-a-cool-idea-and-someone-is-trying-to-patent-it/

 

PATENTLY OBVIOUS?

3D printing chocolate is a cool idea, and someone is trying to patent it

By Leo Mirani @lmirani April 24, 2013

Yes, but does it come in fruit ‘n’ nut? Jens-Ulrich Koch/dapd

If there is one thing the patent wars in the mobile industry have taught us, it is that the price of innovation can be ruinously expensive. By one estimate, there are over 250,000 active patents affecting smartphones, or about 16% of all patents presently in force in America. One reason for that astonishing number is that patents are granted not just for groundbreaking innovations but also for relatively straightforward things such as the “slide-to-unlock” feature on the iPhone. That means lawsuits or hefty license fees for those who want build on existing work.

Observers fear that the young and rapidly growing field of 3D printing could fall into the same morass. At the moment, 3D printing is seeing a lot of innovation coming from enthusiasts who openly publish and share their work. But if applications to patent similar technology are granted, that means innovators may find themselves unable to use existing ideas for the 20-year life of a US patent.

A coalition of groups is now trying to ensure this does not happen. The Electronic Frontier Foundation, a two-decades-old American digital rights advocacy teamed up with the Cyberlaw Clinic at Harvard and Ask Patents, a Q&A site, to challenge a series of 3D printing-related patents pending approval in the US. Among these is one that seeks to patent the technology required to 3D print chocolate.

Kit Walsh, a lawyer at the Cyberlaw Clinic, says that challenging that particular patent is not really about chocolate, but about the idea that chocolate is just another material that can be melted and later solidified into new shapes. “If you let people get patents on every material that has those properties, you’re going to occupy 3D printing,” he said over the phone from Cambridge, MA.

The goal of the coalition stretches beyond protecting 3D printing. Walsh says they will expand their efforts to challenge patents related to mesh networking technology, a  new form of wireless communication. But the bigger idea is that their submissions could serve as a model for people who want to use a new procedure.

The group uses a provision in the America Invents Act, a new law that updates the United States’ creaking patent rules. The provision allows third parties—anybody from interested individuals to big corporations—to submit “prior art” that could help patent examiners determine whether an invention is obvious, and therefore unworthy of a patent. It is particularly enlightened law that should help those seeking to challenge patents as well as examiners themselves.

For challengers, it means a relatively simple, lawyer-free method of submitting prior art. In the past, the only procedure was a re-examination request, which could cost up to $20,000. By contrast, the new procedure is free for anybody making less than three submissions and just $180 for every 10.

Examiners too benefit because 3D printing covers a number of disciplines from chemistry to mechanical engineering. Individual examiners cannot be experts in every field, so additional submissions help them make better decisions.

Arduino Mega Pololu Shield – RAMPS information & schematic

RepRap Arduino Mega Pololu Shield, or RAMPS for short. It is designed to fit the entire electronics needed for a RepRap in one small package for low cost. RAMPS interfaces an Arduino Mega with the powerful Arduino MEGA platform and has plenty room for expansion. The modular design includes plug in stepper drivers and extruder control electronics on an Arduino MEGA shield for easy service, part replacement, upgrade-ability and expansion. Additionally, a number of Arduino expansion boards can be added to the system as long as the main RAMPS board is kept to the top of the stack.

Contents

Introduction

Version 1.4 uses surface mount capacitors and resistors to further cover edge issue cases. As of version 1.3 in order to fit more stuff RAMPS is no longer designed for easy circuit home etching. If you want to etch your own PCB either get version 1.25 or Generation 7 Electronics. Version 1.25 and earlier are “1.5 layer” designed boards (i.e. it’s double sided board, but one of layers can easily be replaced with wire-jumpers) that is printable on your RepRap with the etch resist pen method, or home fabbed with toner transfer.

This board is mostly based on Adrian’s Pololu_Electronics and work by Tonok. Copper etch resists methods suggested by Vik. Also inspired by Vik’s work with EasyDrivers. Circuit design based mostly on Adrian’s Pololu_Electronics. Joaz at RepRapSource.com supplied initial pin definitions and many design improvements. Much inspiration, suggestions, and ideas from Prusajr, Kliment, Maxbots, Rick, and many others in the RepRap community.

  • Mendel printed RAMPS wired to Mendel.

  • Mendel with RAMPS in enclosure mounted.

  • screen capture of 2-sided RAMPS layout

  • commercially fabbed 2-sided RAMPS wired to Mendel

Features

  • It has provisions for the cartesian robot and extruder.
  • Expandable to control other accessories.
  • 3 mosfets for heater / fan outputs and 3 thermistor circuits.
  • Fused at 5A for additional safety and component protection
  • Heated bed control with additional 11A fuse
  • Fits 5 Pololu stepper driver board
  • Pololu boards are on pin header sockets so they can be replaced easily or removed for use in future designs.
  • I2C and SPI pins left available for future expansion.
  • All the Mosfets are hooked into PWM pins for versatility.
  • Servo style connectors are used to connect to the endstops, motors, and leds. These connectors are gold plated, rated for 3A, very compact, and globally available.
  • USB type B receptacle
  • SD Card add on available — Available now made by Kliment – Sdramps
  • LEDs indicate when heater outputs on
  • Option to connect 2 motors to Z for Prusa Mendel

 

 

 

Safety Tip

Generation3Electronics-achtung.gif

Once you start putting electricity into your RepRap – even at just 12 volts – you have to take basic, common sense precautions to avoid fires. Just in case these fail, test your workshopsmoke detector. Don’t have a smoke detector? Get one!

Schematic

Current schematic shown. For older versions click the image. Click again for full image. This is the schematic of the shield.

Change Log

  • 1.4 August 4, 2011
  1. Changed capacitors and resistors to surface mount components
  2. Added LEDs to mosfet outputs
  3. Added bulk capacitors for each stepper driver
  4. Added pull up resistors to enable to override the Pololu drivers default enabled state
  5. Added mosfet gate resistors
  6. Added pull-ups for I2C
  7. Servo1 connector moved to pin 11 to free 7 for ADK
  8. Fixed thermals
  9. Servo 5V supply is only connected to VCC if a jumper is added
  10. Reset switch changed for small footprint
  11. Moved Aux conectors around a bit and increased board size ~0.1″
  12. Added some space around Q3 for a small heatsink
  • 1.3 May 13, 2011
  1. Added 5th stepper driver socket
  2. Added 3rd thermistor circuit
  3. Added Heated bed circuit w/ 11A PTC fuse, changed to 4 position pluggable input jack to accommodate additional current
  4. Increased board size to 4″x2.32″
  5. Pin order on heater outputs changed
  6. Increased spacing increased to accommodate different connectors
  7. Added connectors for optional 2 motors on Z driver
  8. Added connector for PS control
  9. Improved expansion connector layout
  10. Moved LED towards corner and added resistor to LED circuit
  11. No longer optimised for home etching 🙁
  12. License changed to GPL v3 or newer
  • v1.2 January 04, 2011
  1. Added 0.1″ motor connector to RAMPS for each driver (motors no longer have to be connected on top of stepper drivers)
  2. Added breakouts for serial and I2C
  3. Changed extra power and pin headers around for easier connection to extra boards.
  4. Lost most extra analog breakouts
  5. More silk screen and bottom layer fixing
  • v1.1 September 30, 2010
  1. Replaced power barrel jack with plug-able screw terminal
  2. Added jumpers to select micro-stepping on stepper driver boards
  3. Added debug LED
  4. Changed mosfet pins to be compatible with FiveD firmware
  5. Reduced number of 100uF capacitors to 1
  6. Added 100nF capacitor to 12V input
  7. Put auxiliary 12VIN and GNDIN pads in a straight line
  8. Silk screen and bottom layer cleaned up
  • v1.0 Original RAMPS PCB design
  • v0.1? Point to point wired Arduino MEGA Prototype shield

    Troubleshooting

    • Check List
    1. RAMPS shield firmly seated on Arduino MEGA
    2. No stray wires/metal to cause short
    3. All connections firmly seated, screws tight
    4. Power connection oriented correctly, connected to RAMPS shield (only USB is connected to MEGA)
    5. Thermistor connected to T0
    6. Firmware uploaded
    7. Stepper driver potentiometers to a sane setting (maybe 25% from CCW to start, adjust to enough power to drive axis + not overheat)
    8. Heater wires properly connected
    • Cannot connect?
      • Verify firmware and host software baud rate matches
      • Disconnect USB, reconnect, and retry
      • It may be a problem with the software you’re using (repsnapper). Try using pronterface.
    • Stepper motor getting too hot?
      • Adjust the potentiometer (small screw) on the stepper driver in question by rotating the screw counterclockwise to decrease the current going to the stepper motor.
    • My fan is not working.
      • If you have RAMPs 1.3+ and sprinter firmware (set with the default pins for RAMPs 1.3), try attaching the fan to D9 output.
      • In pronterface, the fan can be turned on by using the M106 command and turned off with M107.

    Stepper Driver Testing

    If you are not sure whether you have a problem with your RAMPS or the stepper drivers you can test that the driver is getting the power and signals it needs to work.

    • Stepper motors getting too hot?
      • Adjust the potentiometer (small screw) on the stepper driver by rotating the screw counterclockwise to decrease the current going to the stepper motor.

    Use a meter of some sort to test the signals at one of the motor drivers. Be careful not to short anything out. You can use a (-) pad in AUX-1 for ground and test the voltage on VMOT, VDD, EN, STEP, and DIR. If all of these are working correctly then the stepper driver is likely bad.

                        High(5V) when disabled, Low when enabled  EN-|     |-VMOT  12V (or voltage at 5A side of input power connector
                                                  Set by Jumper  MS1-|     |-GND 0V                 
                                                  Set by Jumper  MS2-|     |-1A     ---------------| <Motor Coil A   
                                                  Set by Jumper  MS3-|     |-2A     ---------------|____
                                         Not used (tied to SLP)  RST-|     |-1B      -----------------/  |  <Motor Coil B
                                         Not used (tied to RST)  SLP-|     |-2B      -------------------/
                                      Pulse High for each step  STEP-|     |-VDD  5V
    Switches between High and Low when driven direction changes  DIR-|     |-GND 0V

     

    Q&A

    • What power supply you recommend for your ramps board. I have just finished assembly and looking at the diagrams for a pc power supply and wondering about the separate amperages for the extruder and heated bed. Can they be higher amps without damage?

    Yes, the power supply being capable of more amps than required is the desired configuration. The current shown are the max supported by RAMPS and is the minimum the power supply should be capable of. It is also OK to have both of the inputs on RAMPS connected to one PSU with enough capacity. If you are not using a heated bed the entire thing can run off the 5A side (D8 will just not work).

    • I got a RAMPS V1.3 as part of a kit, but it doesn’t have any installation instructions – just a schematic. Can you point us to a good tutorial for connecting everything? (i.e. stepper motors, opto flag pcb’s, power, data, etc) Some of it (like the single USB port) is obvious, but some of it isn’t.

    See RAMPS1.3 for instructions for version 1.3. There is a version navigation bar at the top of the RAMPS pages that allow you to jump to a specific versions instructions. There is a very helpful graphic under Final Check section.

    • For RAMPS V1.3 the power section of the schematic shows several places with GND/12V (C4/C6, X4-2/1, X4-4/3, VCC/D12). Which one is the GND/12V from the power supply? Is it the round power plug like a laptop power plug? Also, is the outside of that plug GND while the inside is +12V? My kit came with a note warning not to reverse the input power or it would cook the board . . . and a plug adapter with no labels that can be installed either way.

    See the connecting power section of your version’s page. The round plug is on the Arduino MEGA and will only power the MEGA. You need to power the green pluggable connector, it should not be reversible and the board should be marked (+) and (-).