Design and make a 3D mold. Produce a fiber composite part

For this assignment, students were asked to realize a 3d mold in order to produce a fiber composite object. I decided to combine also other assignment I did during FabAcademy and more specifically I have chosen to realize a shell for the chair I made during "CNC Machine Assignment".

Lasercutting Mold

I thought it was I good idea to produce a mold using cardboard and lasercutter. After drawing the curves and do the nesting, I saved in .dxf and imported in Visicut.

The outcome is the following: 36 spare parts made by cardboard, which will be connected through 3 threaded rods, 8mm diameter.

Producing Fiberglass object

I used polyester resin and fiberglass from Sintolit. Here is the Datasheet and the Material Safety DataSheet for Catalyst and Material Safety DataSheet for Fibroresina.

Since these materials are hazardous, the use of glasses, gloves and mask is highly recommended.

Once the mold was ready, I cut the fiberglass cloth with the size I needed. Then, I poured 100gr of resin plus 2% of catalyst. It is important to shake for a couple of minutes maximum, since in 15 minutes the resin starts to become hard. I poured the resin onto the mold and then overlap a layer of fiberglass, adding the remaining part of resin. The part can be completely dry after 90 minutes.

The first result was not so good, since the surface is not very smooth. So I tried to put some tape on the mold, using also a piece of fabric overlapped by resin and fiberglass.

I also tried with some layers of leather/resin/fiberglass/resin/fiberglass, after consulting with Enrico Bassi. The outcome is for sure a heavier but extremely more resistent the the pieces I have made before.