To make my assignment I decided to make a piece with a 3D form formed in a two side mold made in the router.

 

First i got an image from Internet and make the vectors to use them in the Vectric Aspire software to convert the image in a 3D machinable image so I could get the G codes to machine them.

 

To get the codes first you have to upload the closed vectors to Aspire, the select them and choose the characteristics we want.

In this case I assigned 10 mm in height but found out it was too high so I reduced the form to 7mm.

 

I then made the positive and negative parts of the mold.

 

You can find the Aspire archives and the milling codes for positive and negative part of the mold by clicking here.

 

I was adviced, at the Latam meeting,  to make one part of the mold in a soft material to achieve better results.

 

When I made the "negative" part of my mould it seems that the tool spins too fast and heated the pink foam so it started to burn it.

 

Then the tool filled with gooey stuff and I paused the process and took a piece of MDF  and while spining I took off  the gooey stuff.

 

For some reason I don't understand after taking the stuff off the tool stopped burning the pink foam. May be because of the chips. A good issue to investigate.

 

After finishing the hard part of my mold, made in MDF I put some grease to avoid fiber to stick on it.

 

Once I had the molds done I used burlap and resin to make my composite. I cut the burlap in little pieces then I covered the mold with plastic film for easier release.

 

Then I prepared the resin using 100 ml of PP-250 resin with 50 drops of catalyst.

After mixing Resin and catalyst I applied 3 layers of burlap. On each layer I applied the resin with a brush. The last layer I used a complete layer to finish the product.

 

Then I put the mold together and press it with two clamps for about 2 hours.

I am very happy with the result. The piece is very strong for being burlap, flexible, and the finish is very warm, in the sense that it does look natural.

I used too much resin so there are some parts where you can see some resin on the finished product. That is a learning for next time.

The other learning is that Some people on Fab Lab Puebla made part of the mold with thermoforming process. They had great results with less effort, so I am going to experiment with my cnc machined mold and thermoform it with estiren to make the counter part.