Saturday, October 6, 2012

Printed Fins, Futures Base

Here's a project tangent: 3D printing fins.

When I first got this buggy plastic extruder a year and a half ago, I printed a couple tiny fins before the original motor began to fail. Just recently I pulled the contraption back out and fixed it up enough to print out some replacement/upgrade parts to make it much more reliable (the white gears in the picture). So now I'm back in the 3D printing game, with this extruder temporarily bolted onto the CNC router.

The quality with this setup is just good enough to start making mechanical parts for surfboard-related schemes I'm working on - but also good enough to play around with printing small fins.

I've got about 4.25" of vertical travel with this setup. So a fin with a half-inch deep Futures box base can only be about 3.75" tall. That's what you see here:

Anybody see the big problem with this fin? No - not the little crack at the trailing edge. Not the slightly textured surface. There's something wrong with the base. The base is almost perfect. But ...

it's backwards. That's right, I designed the base with the notches switched around. But it does fit nicely in the box, and only took a little touch up sanding work. So, yeah, fail, but success anyway.

I've only got this one early board with Futures boxes, and the box mount job itself is a bit funny. I mounted too shallow and sanded too much, so the boxes aren't as deep as they should be. That's why the base sticks up a bit here. The grub screw pins it down though, and the fit is tight, so it's secure.

Now, about 3D printing: the technology to print a surfboard has been here for a while. It's probably been done, though I haven't seen it. Maybe you have? Maybe secret prototypes are out there incubating, and we'll see the printed surfboard start-ups emerge soon.

What I'd like to see is some cheap, tall, RepRap-derived 3D printers built in garages, apartments, dorm rooms, able to print a 6' board overnight from maybe $50 worth of biodegradable - maybe even self-recyclable - plastic. It looks like that's possible today. Maybe a first step would be to build a printer with a 12"x4"x6" envelope, and print a board in sections.

Add that to my tangents list. The main focus now is on building a laser cutter, so I can develop more detailed cardboard core designs, and designing and printing parts for a servo-driven coelostat, for the SolarCNC project.