Fab Academy 2015

Fab Academy

How to Make Almost Anything...


Composites

Weekly Assignment

This week we have to design and make a 3D mold (~ft2), and produce a fiber composite part in it. In my case, I'm going to design the cover of the aquarium using black burlap and acrylic resin.

Mold design

As on previous occasions, I made the design on CATIA, this time it was a little different because I had to cut the design into 3 parts since the maximum height polystyrene is 29mm and my design has more than 60mm high.

Cover Design

Milling polystyrene

To mill the polystyrene, I used the CNC with a milling cutter for this material (6mm mill) and the "Modela" with a 3mm mill. I used the Modela to create the top, the smallest part where the LCD is housed, this part is very small and it is impossible do it with the CNC.

To mill the foam I'm going to use two machines, the modela (for the small pieces) and CNC. On the CNC I used a 6mm mill (special for foam), the speed of rotation of the head will 24.000rpm. In the modela I use a 3.175mm mill and a standard configuration (the same strategy I used in the molding).

Milling with CNC

Milling with Modela

After milling all parts of polystyrene, I have to glue them using a special glue for this material

Gluing the parts of polystyrene

Creating the composite

To create the composite, I use burlap and acrylic resin I decided to use acrylic resin instead of epoxy because it is not as harmful as the epoxy. The resin is at a ratio of 100 to 50 (100 powder and 50 liquid)

Composite

Before applying the resin and the fabric must be applied release agent. When everything is ready, you just have to get into the vacuum bag and remove all air

The vacuum bag

Final Result

Final conclusion

As can be seen in the final result, the result has not been good, this practice is not going to be useful for my final project, but I have learned much in the process, I have learned that burlap is a very rigid material and is not recommended for jobs that require resolution, another important point is the resin and the amount used, I think the epoxy resin should work much better and respects the color of the fabric without putting whitish.

Source Files