This week I wanted to create a piece of armor, since composites are light and strong. I’ve always wanted to design cool sci-fi armor/stuff, so I created this form in Fusion 360. I created a form, and pulled vertices / edges until I got an acceptable shape. I then exported an STL.
I then took it into blender to calculate the faces for laser-cutting burlap. I wanted to UV-unwrap the model so that I had a series of 2d faces I could laser-cut.
UV-unwrapping manually takes time and patience. I started by marking seams in the model and then uv-unwrapping but the results were not what I expected
I moved on to auto-UV unwrapping based on a 60 degree cut (if there is a 60 degree curve, it cuts the seem).
The results weren’t bad. I then had to figure out a way to bring them into inkscape. The problem was that there was not one consistent shape, it was a series of triangles. I copped out and just traced it with the bezier tool to generate the cuts on the far left.
Here’s the model in the shop-bot partswork3d program. I took care to adjust the cut depth so that the bottom of the model would be flush with the bottom of the foam.
Milling through foam went super fast.
The bottom wasn’t as flush with the bottom of the foam as I wanted it to be, but it was still close enough that I could break off any extra pieces. In retrospect, I could have gotten a much smoother finish if I had reduced the finishing step-over (currently it’s 10%).
Major Fail Alert:
I laser-cut my pieces, covered them in epoxy, and placed it on the model. The line-up wasn’t exact, but that was OK since it would all be vacuumed together.
I then placed all of it in a vacuum bag and attached the vacuum. I tightened the air-lock, and then turned on the vacuum. The air in the bag wasn’t sucked out because the air-lock was sealed, resulting in a the mess you see to the left.
I got help from Jasmine Rubinowitz and John Difrancesco in properly attaching the vacuum. That process went smoothly. THe resulting piece has got extra on the sides, and needs to be machined with a ban-saw. I hope to do that soon. It’s very strong though, and I’ve tried standing on it.