MakerBot Industries

Sliding Parts

As my clockwork spider project develops, one of the goals I’ve had in mind is a final end design that can be assembled by hand, without tools, or additional hardware. ¹  This is an ideal to which I hope I can adhere.  I just like the idea of printing off a plate of parts, handing them to someone, and letting them assemble all of the bits on the spot.  Getting a box of Legos is fun in part because it comes with absolutely everything you need.  Without a barrier to assembly, the part out of which the toy is assembled are toys in and of themselves.

If one is to design mechanical parts, I think there are two important considerations.  The first consideration is just how close can two objects be designed and printed such that you don’t need too much force to snap them together tightly.  If the tolerances are too tight, perhaps the parts can’t be reliably printed or easily fit together by hand.  If the tolerance are too loose, the parts won’t stay together.  The second consideration is just how much clearance parts need before they can rotate or move against one another smoothly.  Too tight and they’ll bind, catch, or seize up.  Too loose and they’ll wobble out of place or simply not connect to other critical parts reliably.

After several revisions, I’ve found a “sweet spot” for parts printed with my Thing-O-Matic:

• Interlocking Parts: For a part that needs to fit tightly within another part, I design them so that they have 0.25mm clearance on all sides.
• Moving Parts: For a part that must easily slide within another part, I design them so that they have 0.5mm clearance on all sides.

After some tuning of my profile² I think I might revise the “moving parts” tolerances to 0.4mm clearance on all sides for a fit with less wibbly wobbly. ³  And if one is to use tools, such as a vise or pliers, and not rely on hand pressure, a clearance of 0.2mm on all sides would probably work for parts that needed to stay locked together.

Do you design mechanical parts that need to fit together?  What kinds of tolerances do you use in your designs?

1. Photo courtesy of j-ster [↩]
2. Again, with Dave’s Profileinator – the only way to tune a profile [↩]
3. Or timey wimey. [↩]

Thanks to all the MakerBot User Groups who have completed Challenge #1!

User Groups as far away as New Zealand have met the challenge by meeting up and bringing their MakerBots together.  We enjoyed seeing your bots, faces and secret laboratories. Check your mailboxes because your MakerBot Care Package will be arriving soon! The fun doesn’t end here; MakerBot Industries will host a MakerBot User Group New York meeting at their Brooklyn based headquarters, the Botcave. You’re invited to visit the Botcave to exchange ideas, check out the Botfarm and print some awesome things. Bring your best objects for a MakerBot User show and tell and, of course, a group photo!

MakerBot User Group New York
Wednesday, April 6, 2011
7 PM – 9 PM
87 3rd Ave, Brooklyn, New York 11217

Subway: N, R to Atlantic Avenue – Pacific Street; G to Fulton Street

WIRED: Limor Fried, Our favorite CoverGirl

It is just not everyday that you walk by a newstand and see an actual DIY tech hero on the cover of a glossy magazine.  This month, things are different.

Congrats to Limor Fried and Adafruit from your devoted fans at MakerBot Industries!

Limor Fried, our clear favorite on the newstands

I’ll be speaking at Thingmakers in London on May 4th. They’ve got an impressive lineup that should make for an awesome day of 3D printing awesomeness. Check it out and hope to see you there!

You didn’t think I’d let you off that easily did you?  There’s so much more to learn about OpenSCAD!  I’ve put together a series of tutorials on using this amazing powerful program.  If you haven’t scanned the tutorials or just tried using the program you’re really missing out.  The commands and interface are simple and straight forward and the benefit of being able to generate a printable STL each and every time is a huge benefit.

In this OpenSCAD tutorial series so far we’ve covered the basics of the OpenSCAD interface, how to make 2D forms, how to make some basic 3D forms, how to position those forms in 3D space, the different ways to combine forms, and how to create mashups of one or more existing STL’s and OpenSCAD forms.  Although I described the last two tutorials as “intermediate” levels, that’s really only because you learned the basics so quickly from the first few tutorials.  With just the basics you can literally design anything you can imagine.  The “intermediate” lessons will help you do everything you’ve already learned – but easier, more efficiently, and more reliably.

Before we get started, the image is from johnbentcope‘s OpenSCAD tutorial homework.  I’d like to include a picture of your homework next time.  So, practice making something in OpenSCAD, upload it to Thingiverse with an open license, and tag it with “openscadtutorial.”

Today we’ll cover the “module” command in OpenSCAD.

More after the jump! Read the rest of this entry »

Musicians like Daft Punk understand the principle: take a sound, reduce the number of points you’re sampling it by, and by doing so, increase its awesomeness.  That’s 8-bit music in a nutshell.

Thingiverse designer gpvillamil clearly understands this as well, since this poly-reduced bunny looks somehow both more futuristic (and more evil) than it ever did before.  Thanks for bringing the 8-bit principle to 3d.

Tron bunny by gpvillamil

This is a variation on the Stanford Bunny, loaded into Meshlab and then lo-rezzed using Quadratic Decimation.

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