Gnome and Gnome

There is no doubt Tony Buser has definitely done more for the 3D printing community than anyone else when it comes to advancing gnome duplication and teleportation technology.  However, I’m convinced that his SpinScan open source software and hadware has a larger potential besides assisting in the controversial practice of gnome cloning. ¹  Tony hasn’t finalized the materials list, but the final project would probably involve a decent web camera with good low light performance² , a cheap laser³ , a stepper driver, a stepper motor, an arduino, a few bearings, threaded rod, and some nuts and bolts.  The whole lot would set you back around $200 and significantly less if you can scavenge a few parts.

So, if you could scan and print anything, what would it be?⁴

Spinscan by tbuser

Untitled by tbuser

This thing brought to you by

1. I mean, the anti-gnome-stem-cell lobby is just insane! [↩]
2. Perhaps around $100 [↩]
3. He got a $4 laser from eBay [↩]
4. But, perhaps a better question is…  what are you waiting for?! [↩]

SIGGRAPH 2011 - Portable, super-high-resolution 3-D imaging from MIT

It used to be that creating highly detailed microscopic scans required huge expensive pieces of equipment, vibration isolation tables and hours of processing.  Researchers at MIT have developd a cheap small and portable 3D scanner about the size of a soda can that can detect features as small as 0.0001 mm tall and 0.0002 mm wide – and it can create the 3D images nearly instantaneously.

I cannot wait to plug one of these into my Thing-O-Matic!

Hattip to SlashDo

Curling

As printed plastic parts cool the different areas of the object can cool at different rates. ¹  Depending upon the parts being printed, this effect can lead to warping and curling.  Although PLA has a much lower shrinkage factor than ABS, both can warp and curl, potentially ruining a print.  There are some very common ways to deal with this potential problem, the most notable being a heated build platform.  However, sometimes that might not be enough.

1. Use a heated build platform.  A heated build platform helps keep the lowest levels of a print warm as the higher layers are printed.  This allows the overall print to cool more evenly.  A heated build platform, sometimes abbreviated as HBP, helps tremendously with just about any ABS print and large PLA prints.
2. Print with a raft.  Rafts are a printing option in ReplicatorG and Skeinforge.  They’re basically a large flat lattice work of printed material underneath the lower-most layer of your printed object.  They’ll also help reduce warping and curling by allowing your printed object to adhere better to your flat build surface.  Other variations on this are to print with a larger raft and/or a thicker raft comprised of more layers.
3. Calibrate your starting Z height.  A good first layer makes all the difference.  If your starting Z axis height is too high, the extruded filament won’t be able to make a good bond with the platform.  If you think your Z axis starting height is too high, try lowering it by 0.05mm increments until you find a good first layer.
4. Get the right build surface.  Some people have experimented with different surfaces such as steel, titanium, glass, different kinds of plastic, different kinds of tape, and foam board.  However, I find both ABS and PLA seem to stick really well to hot or warm Kapton tape.
5. Clean your build surface.  ABS and PLA stick better to a clean build surface.  Keep it clean of dust, pieces of old prints, and any other debris.
6. Print slower.  Printing slower allows finer detail, better adhesion to the build surface and lower layers, and gives the printed part more time to cool evenly.
7. Print cooler.  Printing at a lower temperature isn’t always an option.  Ideally, you should be printing at the lowest temperature required for extrusion and that allows good interlayer adhesion.  However, trying lower temperatures isn’t for the faint of heart.  Printing at a too low a temperature could cause harm to your extruder motor or extruder.
8. Eliminate drafts or enclose your robot.  Forrest Higgs found that having his 3D printer too close to an open window caused very uneven heating across his build surface.  This in turn caused the side of his prints closest to the window to curl.  Since keeping the window closed wasn’t an option for him, he compensated for the window drafts by adding a heat lamp.  Cupcake and Thing-O-Matic owners might have an easier time of eliminating drafts by simply enclosing two or three of the sides of their robots.  It will also have a fortunate side effect of helping to control fumes.
9. Design with mouse ears.  Zach Smith’s solution was to add little discs to corners of an object to help those corners stick to the platform.  These essentially serve as “mini-rafts” to give those corners more surface area and better adhesion without having to print an entire raft.
10. Design with aprons to hold down corners.  Forrest Higgs suggested adding “aprons” around an object to be printed, while that object was being printed on a raft.  These low thick pieces of plastic help keep the raft flat and help prevent any curling or warping from affecting the desired printed object itself.
11. Design with surrounding thermal walls.  While Forrest Higgs’ apron approach provides a mechanical advantage of essentially holding down corners with a chunk of plastic, Nophead has added thin surrounding walls to his designs to act as baffles to keep warm air around the printed object as it moves around.  He’s postulated that a very thin surrounding wall could have the same beneficial effect as printing inside an enclosed build chamber.  Interestingly, it seems that Nophead suggests that designing objects with more rounded corners might also help avoid curling and warping at those corners.
12. Reduce infill.  When printing a model you can chose to print it hollow, completely solid, or some percentage between zero and 100.  However, as Nophead points out even the plastic inside a model exerts a force on the entire printed object as it cools.  It stands to reason that the more plastic you have, the more those pieces of plastic will pull against themselves and the build surface as they cool.  By reducing infill there will a reduced amount of internal tension as the object cools.  Reducing these internal forces by printing with a lower infill ratio can help reduce curling and warping as well.
13. EDIT:  Sand the Kapton.  Charles Pax has suggested that sanding a Kapton tape build surface will increase the surface area, making it easier for the molten plastic to stick.
14. EDIT:  ABS surface.  Some have suggested essentially painting the build surface with liquid ABS.²  This is has the same effect of laying down a big flat raft.

If you’ve got some suggestions, tips, or tricks that you use to fight warping and curling, please leave a comment below!

1. Photo courtesy of backpackphotography [↩]
2. ABS dissolved in acetone or ABS glue [↩]

Duplicating Disc Detainer Keys by nrp

Thingiverse user nrp has been working on using his 3D RepRap printer in some pretty amazing ways.  He’s already put his 3D printer to use along with a Kinect to print by use of hand gestures.  Since then he’s been working on duplicating house keys and the more secure disc detainer keys pictured above.  Nrp’s website, and the comments that go along with his detailed posts, provide a wealth of information about his project along with lots of interesting links about computer enhanced key generation.

This project and the way nrp uses his printer remind me of the very cool Nickel for Scale project by Amy Hurst and MakerBot’s own Marty McGuire.  How cool would it be to never have to go get keys made again?  I don’t think it’s too much to dream that one day you might be able to put a key down next to a nickel, take a picture or short video, and have your MakerBot crunch out a few duplicates.

Untitled by nrp

This thing brought to you by

Untitled by nrp

This thing brought to you by

0-extra shell on left print, default settings on the right

While perusing Thingiverse yesterday I noticed TheRuttmeister’s suggestions on printing a small 7 toothed gear for a Stepper Upgrade for the MK5.  Here’s his suggestion:

I recommend that you print the small gears with 0 extra shells (infill of 0.1 or higher will result in solid teeth).

I had never heard of such a technique, but RoberHunt‘s print of this gear, showing the “zero-extra shells” on the left and his default settings on the right.  However, those results really speak for themselves.  I’ve tried to print small objects before only to find out that I couldn’t get the fill ratio to the point the object was solid.  I’m definitely trying this idea out next time!

Profileinator - By David Durant

Recently I posted about the basic usage of Dave Durant’s Profilinator, a program that will calculate the best print settings for your 3D printer.   In order to get you started with how to use the program I left out two amazing features of this program.  Today I’d like to cover the first of these sweet features.

As some of you already know or might have guessed, his program can provide a range of reasonable print settings, not just a single recommended setting.  If you want to see a range of print settings all you need to do is specify different values for the minimum and maximum for Feed rate, Thread height, and Thread width.  Dave’s program will then solve for the appropriate flow rate given those settings.

How is this helpful to you?

Well, perhaps you may not yet know what settings you want – so one particular set of setting values isn’t that useful.  Perhaps you really like thin layers?¹  Perhaps you’re not sure about how thin or thick you want each extruded thread to be?  By specifying a lower minimum and a higher maximum for the Feed rate, Thread height, and Thread width you’ll get a list of every permutation of these variables² with the appropriate Flow Rate.  Now you can experiment freely printing using any of those settings and find out first hand which layer height and which thread width you really appreciate.

Based upon your particular hardware and configuration, you may discover your robot’s limitations. ³  After printing for a while, you’ll get a good feel for how fast you can run your robot’s XY platform. ⁴  Once you know an optimal feed rate for your robot⁵ then it’s a matter of picking other settings.

Rather than spending your time filling up your home with calibration cubes, trying to discover your optimal settings – using the ranges of settings from Dave’s program you can choose which of a range of good settings you most appreciate.

Bonus Info:

Dave mentioned during our conversation that he was able to reduce either the layer height or thread width without a big change to printing speed – but that reducing both at the same time would increase print time. ⁶

1. Low layer heights. [↩]
2. At the specified increments [↩]
3. For instance, my Cupcake’s Unicorn drawings get a little shakey when I run the platform speed much above 2500. [↩]
4. This is the feed rate. [↩]
5. My Thing-O-Matic’s optimal feed rate is probably between 30 and 35. [↩]
6. I’m going to apologize to Dave, in this cowardly footnote, in case what I’m mis-describing his wisdom. [↩]

Dave Durant - DIY 3D Printer Vertical Resolution World Record Holder

With Dave Durant’s magic printer calibration program I was able to just specify what layer height (vertical resolution) I wanted – and it just worked.  This is a totally new experience for me.  Before playing with this program I spent time dialing in each version of ReplicatorG to my specific 3D printer’s settings – with different settings for my Cupcake than for my Thing-O-Matic.  Now I can just choose my desired vertical resolution and FIRE THE MAKERBOT!  If you’re planning on playing limbo with your computer too, there are a few practical concerns:¹

1. Careful measurement of the filament is important. Printing by laying down 0.2mm thick layers of plastic means your printer has to have a very good idea of how much plastic is coming in and going out.  Dave’s magic program will figure how much is going out, so all you have to do is carefully measure your filament.  I suggested my method the other day.  You don’t have to use my method, but I would suggest that you can’t take too many samples in getting this right.  Printing at 0.2mm layers means that over or under measuring will have a pretty big impact on the amount of plastic deposited at each layer.
2. Attention to the build height is important. Printing at 0.2mm thick layers of plastic means that if your starting build height is off by as much as 0.1mm, you’re basically compromising half a layer of plastic.  Being off by 0.1mm in starting build height just isn’t that much of a problem when you are printing at 0.4mm per layer – there’s plenty of room for the plastic to squish around and find a place to go.  Make sure your Z maximum endstop doesn’t have a lot of wiggle, your platform is hitting the Z maximum endstop in the same area reliably, and that there’s not much wobble or wiggle² in your Z stage that could cause a big variance in your starting build height.  Also, be sure to check your printer’s auto-homing features several times before printing at this level. ³  If you’re not sure about how to calibrate the proper print height, follow these calibration directions.
3. Having a perfectly flat build surface is important. Since you’re printing at such thin layers, inconsistencies in your build surface will be magnified through the layers as you print.  You’ll want to make sure your build surface is totally flat – or flat to within about 0.1mm.  If you’re very close to having a level surface a good way to test it is to print a large flat object.  When that first layer goes down you’ll see the filament fuse together where the platform is at the proper height and either become individual strands where the platform is too low or it will start pushing plastic around where the build platform is too high.  I would suggest calibrating your starting build height for the highest point on your build surface and, if you’re using an automated build platform, you can just slightly adjust the lower points by adding a piece of Kapton tape.  Putting it under the belt in the lowest spots will raise your build surface very very slightly.

Next time – more about Dave Durant’s magic printer calibration program!

1. How low can YOU go!?! [↩]
2. Or wibbly wobbly [↩]
3. A printer head crash isn’t catastrophic, but it is a pain. [↩]

Dual Extruder / Dual Material Makerbot by ScribbleJ

ScribbleJ has done it again!  Not wanting to waste his MK5 extruder he built a mount for it to sit next to his MK6 and wrote some custom code and put together another mind-bending Thingiverse entry. While he says it’s not ready for prime time yet, it’s a huge step forward to printing with dissolvable support material. Don’t forget to check out the video of the dual extruder in action:

Profileinator - By David Durant

This last weekend I was fortunate enough to catch up with Dave Durant to talk about how to calibrate my 3D printers. Not only has Dave written a number of amazingly detailed posts on properly configuring Skeinforge for 3D printers, but he’s also written an amazing program for determining the proper settings. ¹  Although this program has been out for two months, I hadn’t given it a shot until just this Saturday.  Oh!  If only I could capture the lost hours I’ve wasted calibrating my machines when I could just have used this program!  You, gentle reader, need not toil away in front of your machines and may simply use Dave’s program powered by MATH and SCIENCE.  Here’s a quick walk through of how to use his program:

1. Install Dave’s program
   1. The program is just a single executable file that will generate an XML file for storing saved values.  To run, just open the executable.  To uninstall, just delete both the executable and the XML file.  The ZIP file contains more than this single executable, so unzip those if you want them too – but you don’t need them.
   2. You’re going to want to open the program now.  Don’t worry about any of the settings just yet – we’ve got an important step next.
2. Measure your filament’s diameter
   1. Dave’s program works by taking a measurement of the volume of plastic entering the extruder and then providing the values you need to account for the volume of plastic as it exits the extruder.
   2. To calculate my filament’s I took measurements of the filament over the span of about a foot at ten different points.  At each point I measured the filament twice – at 90 degree angles from each other.  Here are my readings (yours should differ).  The first two values on each row are the two readings at each level.  The third value in each row is the average of the first two values.  The 11th line is merely an average of the ten prior averaged readings.
      1. 2.98    2.85    2.915²
      2. 2.84    2.98    2.91 (Average of 2.84 and 2.98))
      3. 2.81    2.86    2.835³
      4. 2.88    2.81    2.845
      5. 2.82    2.86    2.84
      6. 2.86    2.79    2.825
      7. 2.85    2.85    2.85
      8. 2.84    2.81    2.825
      9. 2.92    3.15    3.035
      10. 2.85    3.01    2.93
      11. 2.881mm⁴
   3. As this is the only reading you’ll be taking of your setup, be sure and do it carefully.  If you get this right, you’ll never agonize over Skeinforge calibrations again.
3. Enter your filament’s average diameter into Dave’s program
   1. Try out these settings:
      1. Gear diameter:  If you’re using the MakerBot MK5 Drive Gear, it should stay 10.58.
      2. Filament diameter:  This is where you enter your averaged measurements from the last step.  Mine was 2.88 – yours will differ.
      3. Gear swell mod:  For the moment, just enter “0.90″ if you’re using ABS and “1.0″ if you’re using PLA.  This is where some of the voodoo math comes in.
      4. Flow rate min/max/fudge factor:   0.5 / 5.0 / 1.0
      5. Feed rate min/max/increment:  30/30/5
      6. Thread height min/max/increment: 0.36 / 0.36 / 0.05
      7. Thread width min/max/increment: 0.75/0.75/0.05
   2. Click “Go” to get your recommended settings!
      1. If you entered different values for the minimum and maximum values for Feed rate, Thread height, and Thread width, you’ll have a number of options to choose from.  If you want a profile that will “just work” try out those settings above.  Dave’s first Skeinforge guide defines all of these things, but a very quick overview is as follows:
         1. Feed rate is how fast your XY platform will be moving as you print.  30mm/s is a nice safe bet for speed.  35 should work reasonably well too.
         2. Thread height is the layer height.  Layers at 0.36mm each will give you a good solid, quick printing object.  More layers per millimeter will give you a higher Z resolution.
         3. Thread width is the width of each extruded thread as it is laid down.  Thinner threads will give you a higher XY resolution.
         4. Flow rate is how fast the extruder takes in plastic.  This is the magic value you are solving for with Dave’s program.
4. Enter your recommended settings into Skeinforge
   1. Enter “Thread height” into Carve -> “Layer Thickness (mm)”
   2. Enter “Thread width” into Carve -> “Perimeter Width over Thickness (ratio)”
   3. Enter “Thread width” into Fill -> “Infill Width over Thickness (ratio)”
   4. Enter “Feed rate” into Speed -> “Feed Rate (mm/s)”
   5. Enter “Flow rate” into Speed -> “Flow Rate Setting (float)”
   6. Enter “Feed rate” into Speed -> “Travel Feed Rate (mm/s)”
5. Print!
   1. Print happily secure in the knowledge Skeinforge is powered by SCIENCE!

Fair warning – I’m leaving out two of the coolest features from Dave’s program.  I’ll cover both of these features next time.  However, for right now, as long as you provide his program an accurate reading of your filament diameter, you can basically just tell it how fast you want to print and at what resolution – and get all the settings you need.

1. 1. Configuring Skeinforge:  Basic Settings with David Durant
   2. Configuring Skeinforge:  Five Critical Settings with David Durant
   3. Configuring Skeinforge:  Configuring the Latest Version of Skeinforge with David Durant
   4. Configuring Skeinforge:  Creating a New Profile with THE David Durant
   5. Configuring Skeinforge:  Tuning a New Profile with THE AMAZING David Durant

   [↩]

2. Average of 2.98 and 2.85 [↩]
3. Hey!  Now you’re getting it! [↩]
4. Average all of the averages above [↩]