Full-tilt 3D Printing

If you stop by the Mission St. house in the evening, you’ll find a mixture of work and play.  Some of us might be hacking on a work task we just couldn’t put down.  Others might be playing a game from the latest Steam sale.  Often we’re tinkering with a side project related to 3D printing.  It’s an atmosphere where crazy ideas can nucleate.  Ideas that start out sounding technically infeasible, prohibitively expensive, or not right for our customers, but still are fun to think about and talk about.  And sometimes, maybe, they might just be worth chasing down.

Here’s an idea that solves two big problems in low-cost 3D printing.  It’s probably a bit too crazy for us to pursue right now, but I hope someone picks it up.   Because it’d be awesome to see it come to life.

First, some background.  One big problem with existing low-cost 3D printers is that of printing overhangs.  Printing in plastic means melting it, squirting it out a nozzle onto another surface, and letting it cool and harden.  The first layer is printed onto a flat “bed” and the later layers are printed on top of the prior ones.  But if there’s no surface underneath the plastic, say when printing the top of a dome, gravity can pull down the molten plastic and the final part will be droopy.  There are some workarounds, like printing support material that can be broken off or dissolved away, but that is time consuming and frustrating.

A second problem with such FDM 3D printers is that they only work well when the print bed is level.  If your kid knocks your printer off your desk, or maybe the delivery truck hit a pothole, then the bed can be thrown out of alignment by a fraction of a degree.  With even a small misalignment, the plastic layers won’t be formed with the right height.  Instead of building up your part layer-by-layer, you get a growing glob of goop that sticks to the print nozzle rather than the bed.  But to re-level a misaligned bed, a one needs a screwdriver, a keen eye, and a lot of patience.  None of those are prerequisites for using a 2D printer.  Why should you need them when 3D printing?

With these two problems in mind, we showed off some recent progress to a friend who stopped by yesterday after work.  When it came to bed-leveling, he asked a great question: “why fight the tilt when you could use it?”  That launched an exciting conversation with some crazy ideas.  Why not design the bed to tilt, and actively control it?  Our customers would never need to level the bed by hand, and since the printer could angle any already-printed layers at will, it could print overhangs at almost any angle without droop.

I love moments when a good idea hits.  It takes me a few seconds to process, and then my mind goes in a thousand directions at once.

We started talking about a few of those directions last night: How do we tilt the bed?  (servos? linear actuators?)  How would we know where it is?  (Hall effect sensors?)  How would we modify the printing software to utilize this kind of hardware?

The answers aren’t easy, and we have a lot of other things we’re working on.  A quick web search shows that we’re not the first people to think of this idea, and we probably won’t be the first to implement it.   But it’s one crazy idea I can’t wait to see made real.

[All images from Wikipedia]

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