Partnered with Fab Lab veteran, Adesola Holmes to create a composite. We planned to make a hard-case shell for small, flat electronics. We created a coupon first by cutting out linen corners to wrap the shape of the foam block.
Preparation:Vacuum Bag Workflow:
Laid out all materials to be used for coupon creation:
This link shows how the coupon workspace was prepared BEFORE we started the wet layup process.
We also rehearsed (acted out how to actually go through the wet layup process, using the dry supplies)) at least 3 times before actually mixing the resin, applying it to the fabric, folding it around the foam, placing it in the bag, and finally using the generator. Lots of thorough communication is needed to get this done in less than 90 minutes, so if you have a large piece and you're working with a partner, COMMUNICATE.
Completed Coupon: Bottom and Top
Following Holmes' lead, I had to figure out OpenSCAD. We reviewed images of hard-case shells via Google and proceeded to use the Minkowski script to combine a cylinder and rectangle:
I found an Instructables link to help us get started in the design process, because I have no experience with scripting design programs, except for the time I taught myself how to use AutoCAD 10* while still in high school (that book was bigger than the dictionary!).
We exported the OpenSCAD file into Partworks v.3 to create a toolpath for the Shopbot to follow when machining (cutting) the insulation foam we were to use for our composite:
Here we had to create a toolpath and select our bit for the foam. Again I took to Google to look up an online forum stating what settings to use for machining house insulation foam (purple):
After calculating the toolpath, be sure to preview your settings to view how your object will be cut out of your material:
Due to my inexperience with this machine, I had to run back and forth between editing my Partworks file and the Shopbot to make sure the my part of the case (the top) would machine out:
Laser Cutting the Fiber (Linen):
I designed paper patterns to reinforce the corners for both our pieces in CorelDraw v.5 (now that I finally know how to use it without turning into an ogre) and corner flaps for my piece (the top).
I used the laser cut settings that were recommended for linen with the Epilog Legend 75watts, but discovered that conditions weren't exactly correct for precise application to my piece. I simply ran the same job to cut the linen until it cut all the way through as the work day was ending and I was running out of time:
Preparing the Composite Wet layup:
We followed the same steps as we did in preparing the coupon composite. The only difference was that we almost used the entire 90 minutes (the potlife time for the resin to be applied and used in the vacuum before it's no good) to get through the wet layup process for both our pieces. We used 3 layers for the sides that mattered and an additional 3 layers per corner, using our linen fabric tabs.
This video shows how I applied resin to my piece.