Composites

This week, the exercise was about composite; design and make a 3D mould and produce a fibre composite part in it, by using air-vacuum bag process. Since you can reuse the mould it allows you to make repetitive things fast. Here is the link to see the details

At the beginning my idea was making wall-clock with glass fibre and cement composite part. But in Fablab Barcelona, we are going to experiment with natural fibre composites: cotton, linen and Jute and bamboo (because of respirators not only for you, but for everybody in the room). and as Luciano has already developed the fabskate, i have decided to make skateboard for myself.
Luciano also gave us some instructions about what all the things you have to take care while designing a mould for the skateboard, my design for skateboard was with back kick and sidekicks i have made a double curvature mould. the size of the the board was 750x225mm, the mould was 750 x 225 x 70 mm. and exported the file as .STL to mill the board in Shopbot CNC machine.
As we have already done the exercise of Computer-controlled Machining, i knew how to use the CNC machine and I used Partworks 3D that comes shipped with the Shopbot to produce the tool-paths. with the 12 mm ball-end bit, i generated three strategies for the: Roughing that will remove most of the material quickly, finishing that will produce the final accurate surface and finally cutout (if needed). Here is the link to download SKATEboard file.

skateShape

Laser-cutting the Skateboard shape from of Bamboo sheet.

now in order to get the desired shape of the skate board, first i have projected shape on the mould i have design, then trim the surface of the shape of my skateboard and then There is a function in Rhino named Unroll the surface that flattens a non-developable (curved in two directions) 3D surface into a 2D flat surface in order to be cut. It is quite a powerful command. also if you want to engrave something on your board its better if you do it before moulding it. so i have decided to do Islamic pattern with Grasshopper and Rhino for the back and for the grip i have made Barcelona map.

Air-vacuum Process

Moulding the Bamboo Sheet with the air-vacuum bag.

Now the air-vacuum bag process, well instead of using three bamboo sheets i am going to use the two bamboo sheet with canvas in between which is much more efficient. as binder, i am using two parts of resin and one part of hardener. well when you mix resin and hardener they form the epoxy. My layers were set up as following: foam mould - peel ply- First layer of Bamboo sheet- Canvas - Peel ply- felt breather. The whole process was around 15 minutes. I finally put the whole thing inside the vacuum bag.

skateBOARD

it took around 7 hours and i had the the shape i wanted for the skate board though its not 100% of the mould but more or less..its quiet good.

now the next step is to cleaning and sanding the board to make it smooth then oiling the board and putting a grip o top and adding the wheels..and its ready to roll..!!