3d Try Try Try Again

On the one hand, 3D printing holds out the promise of design it today, get it tonight. Somewhere along my toolchain I need to account for the shrink factor. Plastic shrinks when you heat it, extrude it, and cool it. ABS shrinks more than PLA. Fusion 360 (aka F360) thinks I’m working with Steel. In theory I could change the material, but I’ve been tweaking this design for so long that I’m not about to introduce a major change. I’m printing version 23, try number 2 right now. Try number 1 came off the print-bed. This normally indicates that it is time to spray some more “ABS Juice” which is simply ABS dissolved in Acetone. It creates a thin layer of plastic on the glass that allows the ABS being extruded to bond to it.

My particular project is probably about as complex as it gets because I want to control the outer and inner dimensions to create a friction fit on the outside and the inside. The outer friction fit needs to grab the tie-rod end and the inner friction fit needs to grab the ball stud. The combination gives me a way to rehab the 30 to 40 ball joints on my motorhome. All of which raises the observation that these iterations take lots of time. Just one more reason that 3D printing is probably not the future of Manufacturing, at least not in it’s current form. It is a great solution to custom or long-tail manufacturing. It’s also a great solution for niche problems, hobbyists, and tinkerers. I will be using it extensively for my circuit enclosures. I see it as one more value add that I can attach to an open source hardware project. The firmware, the board design, and the enclosure design available in case someone wants to leverage them.

In other news, my Prusa i3 RepRap printer has been performing flawlessly. I’ve been giving it a good workout this week. The Chinese linear bearings are a bit suspect, but I think a little 3-in-1 oil will keep them working good. I actually think a dry lube like Wonderlube would probably be better for them.

I’ve been looking at the 3D scanning arena as well. Ciclops from Spanish company BQ is a pretty neat solution. It’s a rotary table 3D scanner that you can build for around $150-$250. It uses 3D printed parts, some threaded rod, a Logitech C270 camera, a couple of laser line units, and an arduino to produce “dot cloud” scans. They even have some free software called Horus to go with it. The biggest issue I see with the whole design is that it leverages a quasi-custom Arduino with a stepper driver shield. I think this is clumsy and for projects like this it would be better to custom design a single board. It’s very tempting to design the board, build one for myself and release the design. Of course that shoots the whole “cheap 3d scanner” in the foot. There is nothing cheap about board design and iteration. However, when you install an Arduino in a permanent solution I think it should be on a dedicated hardware board. This eliminates the opportunity for bad contacts and makes it smaller.

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