About Week 12

Composites Exercise...

The assignment of this week is related to digital fabrication of composite material: design and make a 3D mold, and produce a fiber composite part in it.

For this assignment I wanted to replicate the owl I realized during the mold and casting exercise with a bigger one version and starting from the negative of the 3D model.

The work is very hard cause the shape of the mold but I decided to try the experiment

In order to produce the negative version of my previous owl with Rhino first of all I made the boolean difference between a box and the face of the owl. This produced the negative and finally I scaled to produce a bigger negative owl.

Download the Rhino file

After this for the molding I used the CNC shotbot and I decided to use the same 2.5 cm MDF sheet.

In order to prepare the produced mdf mold,  I used a water based impregnant in order to avoid any detachment of pieces of MDF and a carnauba wax. I've putted the wax in two different phases in order to produce a wax film useful during the composite release from the mold. 

 

After this preparation phase It was time for the composite fiber composition, and for this phase I decided another risky approach: layering composition

For the textile material I used three different types:

1) thin felt , brown for the base and black one for the eyes

2) a plastic white grid for the eyes

3) A more dense cotton cloth for the final reinforcing fibre

 

Then I prepared the the epoxy resin by mixing component A (resin) and component B (hardness) for 3 minutes with a composition of 100A :25B by weight-scale.

Once the epoxy resin has been prepared I started the layer composition, starting from the eyes, place the resin, continued with the base with the brown felt, passing the roller on each layer, taking care of the edges , critical parts of the operation.

Once I finished I protected all with a plastic film and I waited 24 hours.

After 24 hours I tried to release the composite paying attention to broke the form. It was a hard phase and the the last part a piece of mdf mold came off: maybe less wax or mdf is not the suitable mold material.

It was easy to remove the piece of MDF , more difficult was to remove the composite from the edges , which dimostrates the strength of the realized composite

And finaly the two olws are together

 

Fab Academy - Class schedule 2015

Week 1

Principles and Practices

Week 2

Computer-Aided Design

Week 3

Computer-Controlled Cutting

Week 4

Electronics Production

Week 5

3D Scanning and Printing

Week 8

Computer-controlled machining

Week 13

Networking and Communications

Week 14

Interface and application programming

Week 15

Mechanical Design, Machine Design

Week 16

Applications and Implications

Week 17

Invention, Intellectual Property, and Income

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