The Method of Vacuum Casting
By NICE Rapid | Jan 22 , 2020

Silicone mold is one of the methods of prototyping. Its advantages are fast time, low cost and high processing success rate. Using a silicone mold can make more than 20 identical products. Product materials can be: ABS, PP, PC, Acrylic, high temperature resistant materials, soft rubber, silicone rubber, etc.

Prototyping vacuum casting processing steps:

     1. Before making the silicone mold, it need to make a prototype. The prototype can use the more common ABS materials, CNC processing and 3D printing are sufficient. After the prototype is ready, start making silicone molds. The silica gel and the curing agent are stirred uniformly. The appearance of the mold silica gel is a flowing liquid, the component A is the silica gel, and the component B is the curing agent.

      2. Vacuum extraction and air bubble treatment: After the silica gel and the curing agent are evenly mixed, perform the vacuum extraction air bubble link. The vacuum time should not be too long. Under normal circumstances, do not exceed ten minutes. The vacuum time is too long. When curing, cross-linking reaction occurs, making the silica gel piece by piece, which cannot be painted or poured. This wastes the silica gel. You can only pour the silica gel into a trash can and take it again.

       3. Brushing or operation process: Brush or pour the silica gel evacuated through air bubbles. Pour on the product (Note: the product or model to be copied before pouring the silicone must be release agent or release agent). Then apply the silica gel to the product. Be sure to apply it evenly. After 30 minutes, paste a layer of gauze and weft cloth to increase the strength and tensile strength of the silica gel. Then apply a layer of silicone, and then stick a layer of gauze, weft cloth, so that it can be done after two times. Only by doing so, the service life and the number of turning molds of the opened silicone mold are relatively increased, which can save costs and improve efficiency.

        4. The production of external mold: the general method and material is to surround the mold with plastic boards or wooden boards, once the mold cabinet is filled with gypsum, the other method is to paint with resin, paint A layer of resin is pasted with a layer of fiberglass cloth, and then brushed and then pasted, and the outer mold can be completed by repeating two or three layers.

 5. The operation method of the filling mold or filling mold: The filling mold or filling mold is used for relatively smooth or simple products. There is no mold line to save labor and time, which is to use the plastic board or glass to copy the product or model you want to copy. Surround the board, pour the evacuated silica gel directly onto the product. After the silica gel is dried and formed, take out the product, and the mold is formed. (Note: The soft mold is generally used for the injection mold. It is easier to release the mold. , Will not damage the product inside the silicone mold). Will not damage the product inside the silicone mold).


After putting it in the oven to dry, cut the silicone mold open and take out the prototypes. The silicone mold is now ready. The above is the processing method of the compound mold. Through these steps, batch prototypes can be made quickly.

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