Friday, May 16, 2014

Fin Core Prints

3D printed hollow honeycomb core keel fins for a mini Simmons build I'm working on.

The thruster center fin halves in the foreground show the orientation for printing.

Probably the most intuitive way to print a fin would be to print it upright, base to tip. But lots of RepRap class printers don't have the height to handle that. I've only got about 4 in. vertical travel.

But if I print halves on their sides, I have closer to 7 in. square to work with.
You could probably shape wood keels in the same time it takes to print these. Maybe faster. So far printing isn't a huge advantage. And they still need to be glassed. For thruster fins, it's nice to be able to generate a matching set of cores with consistent foils. That might be harder to do by hand.

With "The Boardroom" surfboard show coming up this weekend, I got this dumb idea last night to crash the party with a 3D printed surfboard. Figured it might take 12 hours to print a really minimal structure. I downloaded BoardCAD, rendered and exported it's default thruster to an STL, used an OpenSCAD script off of Thingiverse to chop the board into 53 sections, and arranged those into 14 plates of parts to print. I ran the first plate through Slic3r and took the files to my 3d printer and found that the first plate alone was going to take nine hours to print. The whole print job would take around 120 hours.

So I won't be showing up at the Boardroom with a printed board. Maybe someone else will though. I'd like to see it.

And I'd still like to do it myself. I printed about four hours worth of the first plate of parts to get the partial thruster nose pictured. Cancelled the print mid-way because part ends were warping too much.

The sparse fill pattern pictured isn't ideal, but its easy to configure and serviceable. The board surface is a double wall. A single wall might be possible, and twice as fast to print. Don't know if I can defeat warp with parts this size on the printer I have, using ABS. But maybe I'd have a chance with PLA.

Why 3D print a surfboard? Mostly because I'm putting off sanding the lumpy hot coat on the mini Simmons. It's so hot this week. Don't wanna wear that respirator and live in that dust. So ... layz ... ee. 3D printing surfboards is just a ploy to avoid doing the real work it takes to build surfboards.


Tommy Wooley said...

Mike, Hi! this is Tom Wooley, I live on the island of Guam. I dropped you an e-mail but I don't know if you got it. Really admire your work. Have you checked out the shapeoko 2?

I've pondered modifying it to 1' x 2' and attaching a laser head. do you think this would allow me to make the cardboard boards?

You have the stock boards available, but what about if I would like to design the board on boardcad or aku shaper and then ... have you made the program available that you created to make the cardboard cuts?

Mike Sheldrake said...

I'd love to support BoardCAD. I'd love to make my own design system public, or recreate it within other available software like Blender, Rhino/Grasshopper, and/or maybe even in BoardCAD. Do-able. Difficult details. No ETA. But when you eventually get a laser firing, check with me regarding custom designs.

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