Molding and Casting


This week's assignment, was to design a 3D mold, machine it, and cast parts from it.


I decided to make a flexible surface with a refractive shape for my final project (probably is going to change but I wanted to give it a chance). I designed a simple mold for casting RTV silicone for obtaining a flexible modular block.


I designed the piece on Inventor then I exported the model on STEP format and opened in Rhinoceros, next I made an extrusion using the dimensions of a machinable wax block, finally I made a difference between the two solids obtaining the mold.




This is the design of the modular piece.




And this is the mold design.




I milled the wax on the shopbot because the Modela was occupied and I also wanted to try the 3D performance of the machine.


First I fixed the wax block to the shopbot´s base using some MDF strips and screws.




I posisioned the lower right corner of the block to 20cm fromthe edge of the table in X and Y axis (aprox) this new cordenate, became my 0,0.




The milling was divided in two parts the roughing toolpath and the finishing toolpath (I didn´t used the cutting toolpath).


The first toolpath is for removing big amounts of material, and the second one is for getting the final shape of the piece (2 hours of milling in total).




After the mold was milled i casted the RTV silicon on it followint the material instructions (A+B components).




After a couple of hours this is the result, it wasn't really good because some air bubbles get stuck inside and the mixture of the two components.