Tag Archives: Design

A MakerBot printed 3x2x1 Rubik’s Cube!

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Lotu's print of the 3x2x1 Simplified Rubik's Cube

Lotu's print of the 3x2x1 Simplified Rubik's Cube

SWEET.  I’ve been so busy of late123 that I haven’t even been able to print several of the things I’ve uploaded. I’ve uploaded several cookie cutters, with another sitting on my hard drive and one more knocking about in my head keeping the cobwebs company.  I’ve also uploaded my variation on a simplified Rubik’s cube.

Well, someone printed it!  It looks AMAZING!  I wonder if it works properly?  I slapped the design together rather hastily after getting frustrated with my MakerBot failing to print TomZ’s 1x2x3 Rubik’s cube.4

I can’t wait to either get some feedback from Lotu (who printed it) or print up one of my own so I can improve on the design.  I’d really like to make a version that is 100% printed – with a snap joint in the middle rather than a nut/bolt system.  If I go down that route, I was thinking about incorporating what I learned from the fantastic Becco blocks connection system by r3becca.

If you print one of these, please answer the following questions:

  1. Which STL did you use?  The one with all 6 pieces or the one with 3?  Would you prefer printing the pieces one at a time?
  2. How well did they fit together?  Are they very snug?  Too loose?
  3. How well does the nut/bolt work?
  4. Did you have to adjust your Skeinforge settings at all?  Why?  How?
  5. Do you have giant hex wrenches like Lotu does?
  1. Mostly writing nonsense. [↩]
  2. Which is particularly funny since my day job consists almost entirely of writing. [↩]
  3. Which is even funnier when you consider that you can tell I’m doing a particularly good job when my writing is completely incomprehensible. [↩]
  4. Did you catch how I swapped all the numbers around to differentiate my derivative?  I thought that was pretty clever… [↩]

Spare parts

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The last week has been a fruitful one for me, at least as far as printing things on my MakerBot is concerned.  I’ve designed, created derivatives, printed upgrades, updated the firmware, installed the latest (super sweet!) RepG, and even performed some maintenance.

One amusing and useful experiment was the serial production of the Z Axis Wobble Reducers by MakiYoshida.  Using my current settings I printed one.  Then I installed it and printed a second.  The second was a visibly better product.  I installed the second and printed a third.  The third was no better than the second.  I installed the third and printed a fourth.  I then installed the fourth… and didn’t bother to print with it.

Right now I have two of these wobble reducers installed on the front right and back left Z axes.  Installing one on the most warped rod (front right, for those of you playing at home) helped significantly.  Installing the second on the back left helped a little more.  Installing the third on the back right didn’t seem to make much of a difference, and may have been worse than the second print.  I didn’t realize why until I tried to install the fourth Z axis wobble reducer.

Once all of the wobble reducers were in place I found that the entire Z stage was too mobile – and would easily shift from left to right and back and forth.  When you have no wobble reducers one or more warped Z axis rods will force the entire stage out of whack.  When you have four wobble reducers, there is nothing keeping the Z stage steady.  Thus, the optimum number is between one and three.  However, I noticed that having two diagonally across from one another gave me enough wobble reduction to improve the print, but not so much flexibility that it could get pushed around in the middle of a print.

Part of the problem is that this particular wobble reducer will allow nearly unimpeded side-to-side motion.  However, these wobble reducers are also fantastic at compensating for a badly warped rod.  I suspect that mixing different kinds of wobble reducers might be my best bet.  I’m not really that interested in installing one of versions that requires precision rods, since it’s just one more thing I have to source for my MakerBot.  Ideally I can mix and match these two types of wobble reducers to improve the overall print.  The Z-axis floating arrester appears to keep the captive nut more … captive than the Z axis wobble reducers I have installed.  This may provide the exact combination of rigidity and flexibility I need to optimize my print quality and minimize layer shift as I print.

The upshot of all of this, and the reason for the post title, is that I now have two Z Axis Wobble Reducers by MakiYoshida that I’m not using.  Do you need one or two of these and feel like saving yourself the print time?  If so, drop me a line.

New design: Rubik’s Cube (sorta)

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Rubik's Cube for Dummies

Rubik's Cube for Dummies

I’ve already posted about how much I like TomZ’s simplified version of a Rubik’s cube.  Only problem is that I wasn’t able to encourage my MakerBot to print it.  Taking into account some of my ideas, I’ve designed a derivative.  It’s 4:45am at the moment – not a good time to have my MakerBot tooting and beeping.  ;)

Here’s what I’ve done with this version:

  1. Oriented the STL so it is immediately printable
  2. Run the STL through NetFabb to make sure it is manifold
  3. Reduced the number of unique printed parts from 5 to 2
  4. Put the STL together in such a way that you can print up two of the STL’s for a total of 6 parts, ready to be assembled
  5. Shrunk-ified the nubs for that fit into the center pieces
  6. Enlargened the grooves for the nubs
  7. Oriented the three parts so that they would use a minimal raft
  8. Changed the design so it will accommodate a nut/bolt attachment system rather than several additional plastic parts that must be glued together

In a future iteration, I hope to change the middle pieces so that all you need to do is snap the two middle pieces together.  Also, I’d like to incorporate any design suggestions from people who have tested this version.

Open Source Monopolies, Unicorns, and Perpetual Motion Machines

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Want a hint?  They’re all imaginary.

There’s no such thing as a monopoly on a truly open source hardware project.  So what if someone cornered the market on some critical widget?  The plans are open source and your options are infinite:

  • Build your own widget.
  • Hire someone to make it for you.
  • Design an alternate part.
  • Design a new assembly using more available part.
  • Hack a work around until you can get the part.

Or, my personal favorite:

  • Start your own business producing and selling that very same critical widget.

These are not problems.  These are opportunities for creativity and innovation.

Wait a second… that’s not a trap at all!

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I just realized that the second variation of my funnel/one-way-door mousetrap doesn’t really trap mice at all!

Since it is specifically designed to provide an avenue of escape to the mouse, there’s no trapping being done, and I may have just miserably failed the design challenge.  The challenge specifically states that the winning design is the one that first catches his mouse.

Plus, this particular design would require you to drill a 4cm hole and 4x 3mm holes in a door.  I’m guessing this is one of those “cure is worse than the disease” solutions.

Peanut Butter Mousetrap design notes

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I treat this blog as part of my lab notebook on printing and designs to help keep me organized.  Having it automatically add tags, adding a time stamp, organizing everything in chronological order, and then making it available for others to learn and comment back are all just a huge bonuses.

Anyhow, here are some of my design notes for this Peanut Butter Mousetrap Insert:

  1. I was going for a minimal design – minimal plastic, printing, and machine time.
  2. I wanted something that would be “ABS warp” resistant.  Even if you end up with a warped flat surface, clamping the insert between the lid and the jar should even it out.
  3. I wanted a resilient design.  Even if the insert is badly warped after clamping down, a flat surface is not critical to its function and it should still work.
  4. I wanted something that could be adapted easily.  I don’t know how to use OpenSCAD, so a parametric design is kinda out the window.  Even so you could print this object at full size and then cut it down to what you need.  1
  1. For the record, I did download OpenSCAD before designing this.  I just wanted to get it out there. [↩]

First part prototyped!

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I’ve just prototyped my first part for a client!  What fun!

He sent over some design files, we discussed some of the constraints of the MakerBot Cupcake CNC (overhang limits, printing resolution, ABS warpage, build sizes), went back and forth over several iterations of the design, and today I printed it up!

In getting ready to print his part I had tuned my ‘bot over the weekend.  The part has the absolute smoothest sides I’ve been able to print on anything to date with minimal stringing.  I’m really really proud of that print.  The resolution came out so well I want to reprint several prior prints – such as the TARDIS and dalek.

Anyone want a second hand TARDIS?

Making Blocks

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The design question I keep coming back to is “How do I create a reliable interlocking system for blocks?”  My criteria for a robust and useful system are:

  1. The interlocking system should allow interconnections in three dimensions.
  2. The pieces should snap/interlock together reasonably well/easily.
  3. The pieces should stay assembled reasonably well.
  4. The pieces should snap apart reasonably well/easily.
  5. The pieces should not require additional tools to be assembled and disassembled.