Category Archives: MakerBot

All things MakerBot! MakerBots, RepRap, and robots!

New affordable 3D printer – the Ultimaker

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Ultimaker

Ultimaker

Update 3/28/2011:  The Ultimaker is available for pre-order!

Erik de Bruijn along with a newly formed Dutch RepRap group have put together this new design for a low cost RepRap alternative.  The stated goal of their blog is “designing/developing an easy to build low cost 3D printer with a small form factor but large build envelope.”  Erik has invited everyone to comment on this beta design.  It’s interesting to see their progression of prototypes in their second blog post.

The interesting thing about this model is that it combines some of the best parts of Darwin and MakerBot and what appears to be a Bowden extruder.

The very nature of FDM1 means that the robot will only move the Z axis a little bit every once in a while.  One of the design drawbacks to the Darwin was that the heavy extruder head (motors, gears, heating elements) were so heavy that the entire robot would rock or vibrate with the lateral XY movements.  MakerBot got around the heavy extruder head problem by moving the platform in the XY and moving the extruder head only up and down.  This design decision isn’t without it’s tradeoffs, however.  One downside is that their build area is much smaller than a Darwin.  Another downside of the MakeBot design is that once the object being built reaches a sufficiently large volume or height, moving the object around quickly on the XY platform causes it to vibrate, shake, and become somewhat unstable.

One of the main improvements inherent in the Bowden extruder is that it allows you to take the heaviest parts of the extruder head, separate them from the rest of the extruder head, and move those heavy pieces to a different location.  Using a Bowden extruder makes a Darwin style robot much more feasible – the small moveable print head won’t have the mass to cause the robot to become unstable.

It seems that combining either of the X or Y movements with the Z probably won’t matter all that much, since the Z axis will only move about 0.33mm or so per layer and the Z axis typically doesn’t operate at the same time as either the X or Y axis.  Combining the as the new RepRap version II, Mendel, design shows us that combining the Z axis along with either the X or Y axis, but not both, can lead to a very stable configuration.

What I like about the Ultimaker design is that it would appear to incorporate some of the best parts of the MakerBot and Darwin designs. It appears to have a bolt/nut/T-slot MakerBot style assembly structure using thin lasercut wood pieces for the body.  I found these parts to bolt together very quickly.  Contrast this to the Darwin/Mendel structure using lots of nuts and threaded rod and printed plastic parts to hold it together.  At the same time, by making use of a Bowden extruder and the Darwin body shape, it appears to be able to use most of the interior volume for printing.

I suspect it probably uses fewer parts than a typical Darwin, but I can’t be sure.  I also have to wonder about the cost of lasercut wood versus the cost of nuts and threaded rod.

Nice find RepRap Log Phase!

  1. Fused deposition modeling – basically creating a layer and then fusing a new layer on top of that layer in succession to build up an object. [↩]

MakerBots for Teachers

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MakerBot Industries is giving away ten MakerBots to ten teachers at any educational level.  Let’s just consider this my entry:

  • Your name
    • Uh.  I’ll stick with “MakerBlock” for now.
  • Your school’s name
    • Sheesh.  These are getting harder.  Okay, how about “MakerBlock.com”?  No?  “MakerBlock U”?
  • The address you’d like the MakerBot sent to if you are chosen
    • Same place as my last order.  ;)
  • A paragraph describing how you would integrate the MakerBot into your curriculum. Include some description of the learning environment and what you teach
    • I would integrate a MakerBot into my curriculum by using it as a demonstration of iterative design, digital fabrication, digital design, invention, and innovation.  The learning environment is the whole freaking internet. 1  I teach digital plastic AWESOME.
  • A lesson plan that you will implement if you get a MakerBot
    1. Pssh.  Just one?  I’ll give you THREE.
    2. You’ve got a MakerBot, a laptop, unlimited plastic and electricity.  You are trapped in a mineshaft.  How do you get out?
    3. You’ve got a MakerBot, a laptop, unlimited plastic and electricity.  You are trapped in a mineshaft with a tiger.  How do you get out?
    4. You’ve got a MakerBot, a laptop, unlimited plastic and electricity.  You are trapped in a mineshaft with a tiger shark.  How do you get out?
  1. Actually, according to Feedburner and Google Analytics, the number is just a few hundred people a day [↩]

What’s the cost of printing with a MakerBot?

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I’ve wondered for a while about the cost of operating a MakerBot.  Let’s break it down and see what happens:

  • Plastic. According to some calculations on the MakerBot Operators group, the cost of MakerBot ABS is around $0.03 – $0.04 per cubic centimeter based upon a price of $70 for 5 pounds (or 2268 grams) of ABS, a density of 1.2 grams per cubic centimeter. 1  Using the current prices of $81.36 for a 5 pound coil after shipping, I calculate the price of ABS at $0.035 per cubic centimeter.  Since we’re talking about such large numbers, let’s just round on up to $0.04/cc.
  • Time. Skeinforge has been estimating about 85 minutes to print 19 cc of plastic.  This comes to about 4.5 minutes/cc.
  • Electricity. At at $0.20/kWh, a MakerBot probably draws around $0.03 per hour.

Thus,we may estimate the cost of operating a MakerBot in terms of consumption of goods and resources (excluding computer, human, and MakerBot time and wear and tear) as follows, where V is the volume of the extruded object in cubic centimeters or “cc”:

Supposing I wanted to recoup the entire cost of my MakerBot to date and spread it across the entire life of a single 5 pound roll of ABS. 2  Let’s round the cost of the MakerBot, all repairs, and all extra MakerBot related materials up to $1,500.00.  One 5 pound coil would have 1890 cc’s of plastic.  This would come to $0.794 per cc of plastic.  So, I would suggest the cost of buying a MakerBot and printing off an entire coil of plastic would probably end up costing you about $0.85 per cubic centimeter of plastic.

Resource cost of printing a 19cc totally MakerBottable 3x2x1 Rubik’s Cube is $0.80.

Actual pro rated cost of printing a 19cc totally MakerBottable 3x2x1 Rubik’s Cube is $16.15.

Absolute cheapest MakerBot usage I’ve seen anywhere at Metrix:Create for members printing from Thingiverse is $0.30/minute, which would print the totally MakerBottable 3x2x1 Rubik’s Cube for $25.65.

Cost = V * ($0.04/cc + $0.0025/cc)

  1. No one has yet quoted me a price on a pint of tears. [↩]
  2. Printing an entire coil would take about 142 hours. [↩]

3x2x1 Rubik’s Cube assembly pictures

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The design should be pretty intuitive.  However, I went ahead and took some pictures of the assembly anyhow.

As I mentioned in an earlier post, I think this one came out really really well.  :)

3x2x1 Rubik’s Cube – done!

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I’m so happy with the way this has turned out.

I’ve made a bunch of changes since the last revision of this printable 3x2x1 Rubik’s Cube puzzle:

  • I’ve totally redesigned the center barbell connector.  I simplified the design, removed the five support struts for each end and replaced it with a single support strut and a flat hexagon in the center of the piece.  The purpose of the hexagon is to give the barbell more contact area with the raft.  One of the earlier drafts didn’t have as many supports or this flat hexagon, and it tore off the build platform partway through the build.
  • I increased the diameter of the tube between the barbells.  This enabled it to print easier, made it a little more sturdy, and decreased the wobbliness of the barbell when everything is assembled.
  • I also shortened the entire barbell by 1mm, so that the entire puzzle is held together more closely.
  • I made the flat semi-circular tabs slightly thinner so they rotate a little more freely.
  • I significantly redesigned, thickened and simplified the two brackets that the barbell snaps into.  It’s been able to easily withstand numerous couplings/decouplings as well as numerous rotations.  With a few rotations, all parts now rotate easily.
  • All of the parts fit together SO much better than my first draft held together with a nut and bolt.
  • There is a slight bit of sideways flex that can occur with the use of the barbell.  It is really minor and it actually seems to help the puzzle be more forgiving as you manipulate it.  I see this more as a benefit than a design flaw.

The was one design choice on which I waffled.  I considered making the center cubes non-identical, with one having half a barbell stick out and with the other having the internal connector you see now.  This would have removed much of the sideways flex – since the barbell would be stationary.  I did not go with this design choice because whether the puzzle used one barbell and two connectors or male/female center cubes, there would always be some flex caused by the use of a connector rather than a static pin.  And, to be honest, I much preferred the symmetry of having everything assembled out of just three unique parts.

I know I’ve mentioned this before, but I really like the idea of a MakerBot printable toy that can be printed in one go and then assembled without tools or any additional hardware.  I also think this would make a great MakerBot print demonstration.

I’ll post some pictures of the parts a little bit later.

3x2x1 totally printable puzzle cube proof of concept success!

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I’ve printed up pieces uploaded this morning to Thingiverse, tried them together, broke two pieces, modified them, printed, and fit some together.  I’ve just modified the STL for what I hope is the last time.  However, I have the barbell fit snugly into the center cube.  It rotates relatively freely and does not want to pop out.  (Of course, I’m sure it could/would if I applied enough force).  This leaves the outside cubes.  I modified the semicircular tabs a little and will reprint them later.

The only problem is that it takes about 40 minutes for my machine to print up two cube parts and a barbell, since they’re so solid.

The important thing is that I’ve just been able to print up and assemble the crucial mechanisms for this puzzle.  I think the next iteration may be what I needed.

MakerBlock Repurpose Design Contest #1!

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I really like the Pilot G-2 gel pens. They’re basically all I use at work. Although we buy refills, I still end up with a surplus of the pens.1 The pens, although technically disposable, use a small metal spring as part of the mechanism. While swapping in a refill the other day, I thought it was such a shame that this little spring is destined for a landfill. 2

Thus, I propose a contest!  I think of this as a repurposing and/or recycling contest.  What’s the most awesome MakerBot printable thing you can design that re-uses any of the parts from this pen? 34

How to enter?

  1. To enter upload your designs as an STL and the original design files to Thingiverse
  2. Then leave a comment on this post with a link to your design!

What are the rules?

  1. The design must incorporate one or more parts of the Pilot G-2 gel pen.
  2. Must be MakerBot printable.  So, keep in mind size, time, overhang, and resolution requirements.
  3. It’s under the Creative Commons Attribution Share-Alike license.

What are the prizes?

The prize will be a print of your choice of either anything I’ve designed and posted to Thingiverse (except the Unblended Mendel – I didn’t really design that) or your winning design!

  1. What it really boils down to is that I’m a pen thief. I walk into a room, pick up a pen, start writing something, put it into my pocket without thinking about it, and then walk away. LRR. [↩]
  2. Of course, there are also other little bits that could theoretically be useful. [↩]
  3. Awesome as judged by me, obv. [↩]
  4. FYI, I’ve already thought of the topic for my next Repurpose contest… [↩]

Working with MakerBot

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MakerBot is looking for a web code warrior.

This is one of those things where I can think of a thousand reasons to NOT do something and only one reason to do it.  In the “NOT” column would be the long commute (CA to NY), I’m not a professional programmer1 , and the job requirements are a little beyond my abilities.

That said, the reason in favor is…  it would be awesome.

  1. However, I do have some mean WordPress plugin chops [↩]

Improving on the 3x2x1 Rubik’s Cube

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I’ve been fiddling with the designs for the 3x2x1 Rubik’s Cube incorporating some of the changes I had considered:

  • I’ve widened the holes for the nut and bolt.
  • I’ve made all of the cubes solid.  I think it will just work better with solid parts.  I had left the four end cubes mostly hollow to:
    • Improve printing time
    • Use less plastic
    • Possibly make an interesting hiding place for something very small
  • I’ve shortened the “stem” that connects the semi-circular tab to the end cube to allow for a more snug fit.
  • I’ve made the semi-circular groove in the center cubes narrower, to allow for a more snug fit.
  • Make these cubes solid so that they slide against each other easier.
  • I’ve noticed that the nut and bolt I installed into either side of the center cubes were pushed sufficiently well inside that they don’t want to come out or rotate.  This is a very good thing for this design!  It turns out that if you rotate it too much in one direction, you can just rotate it back a few times and it will be tightened back up!  It also makes for easy disassembly/reassembly – just rotate the puzzle until it comes apart and rotate it back together to reassemble.