1. Master Model Building.
First of all, producing vacuum casting prototypes require a high-quality master model with high dimensional accuracy. To ensure the final vacuum casting parts are the same as expected, creating flawless master model is the vital foundation. Master model can be created by 3D Printing or CNC Machining, and dedicated post-processing, grinding, for instance, is necessary. These steps make sure that the master model is perfect to use. At Wenext, we will go through all details before making the master model, like design file checking to guarantee a manufacturable master model.

2. Silicone Mold Making.
Master model is ready to use. Then it’s time to pour liquid silicone into the casting box and fully immerse the master model. It takes several hours to cure the silicone naturally. After the mold is cured, cut open the mold and take the master model out of the mold. You will see a hollow space in the middle of the silicone mold, which fits the dimensions and specifications of the master model. Later on, the silicone mold needs to be cured again at a high temperature in an oven because the mold is still soft and sticky. Curing time would be based on size of the mold.

3. Parts Producing.
The final step is casting parts with the silicone mold. Before casting, clean the surface of the silicone mold again is necessary. Then spraying the silicone mold internal structure with special release agents, attach tape to the edge, and even insert steel bars inside for large mold. All these steps make sure that mold release without damages. Prepare polypropylene (PP) in advance, then fully fill the mold with PP, the process is done in a vacuum chamber for degassing, ensuring air bubbles are removed. Afterwards, move the PP part in an oven for curing. Curing time is based on part size as well. The vacuum casting PP part can be removed from silicone mold after cool down.