FDM 3d Printing for Stop Motion

As I mentioned in the last post, one of my aims for the project was to create a fully functional 3d printed armature for stop motion. 3d printing for stop motion can’t offer the kind of strength and reliability of traditional materials used in armature construction, not on a budget anyway, but it is a lot more accessible. My hope was that well designed joints would be able to withstand the rigours of stop motion animation. And when parts inevitably did break they would be easily reproduce-able.

This wouldn’t be the first time of course that 3d printing for stop motion has been developed. But that tends to be much more expensive SLS or SLM printers that produce high quality prints for face replacement or similar. I’ve always felt that this method takes something away from the puppet design and creates a much to polished look. It would also be near impossible on a cheap FDM printer such as mine.

Speaking of which. Here is the printer Billy’s whole armature, eyes, teeth and several props and rigs were printed on:

The Mendel90 was a kit printer that’s no longer available. It was based on the Prusa Mendel and is essentially very similar to most low to mid range 3d printers available now. It has a heated bed that allows for ABS prints and most of the prints for the armature are ABS. I chose it over PLA because in my experience its a bit tougher, easier to sand and can be welded together with acetone.

The main joint that makes up most stop motion armatures is the ball and socket joint. Usually made from very hard steel, it relies on having a smooth surface on the ball and socket to create a reliable and smooth joint with a good amount of movement. The difficulty with 3d printing a ball and socket joint is that its difficult to print a smooth and perfectly round ball. Even if you achieved this, the ball would undertake a lot of wear and quickly become unusable.

To get around this i designed a universal joint that can be tightened on each axis. This uses a small square, with a hole going through the centre on 2 axis, one axis also has 2 nut traps.

The cube is gripped on two axis by a horseshoe shaped piece. One has a bolt that goes all the way through and the other has 2 smaller bolts that tighten against nuts dropped into the nut trap.

The result is a joint that is strong and can be tightened on both axis. It can also be moved repeatedly without becoming loose. Variations of this joint were used throughout the armature.

These joints nearly all lasted the duration of the animation, with only two needing replacing, one due to over tightening and the other because the puppet was dropped. They did require regular tightening where joints were in heavy use, and i’m certain improvements could be made to the design to improve their usability. 3d printing for stop motion is possible and I believe it could become a realistic alternative to make armature design a lot more accessible.  Especially with the continual development of new materials, things can only get better!

James is the writer/director of Billy Whiskers, scribbling haphazardly on this website to document and share the experiences of making a stop motion animation.

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