In the prototype fabrication,Vacuum casting is a common machining method. Mainly used for small batch of plastic prototype customization, the general number of dozens to hundreds of plastic prototype, using the method of vacuum casting processing is more cost-effective.

     The disadvantages of prototype by vacuum casting:

         1. Shrinkage and deformation. Since the vacuum casting uses the principle of thermal expansion and cold contraction, if we make the prototype according to the size on the customer's drawing, the liquid in the silicone mold will inevitably shrink after cooling, resulting in deformation. Generally, we use the method of vacuum casting to make the prototype. we should make it a little larger than the size when make the vacuum casting.

        2. Low high temperature resistance,Because the vacuum casting material is liquid, It is made by heating and cooling at high temperature. Therefore, in terms of performance not as good as processing directly processed on the plate. Usually, the prototype processed by CNC can reach about 100 degrees in high temperature resistance. And the prototype by vacuum casting only able to withstand about 60 degrees of high temperature. In addition, the vacuum casting that in the strength, hardness, these aspects can not compare with CNC machining.

    The advantages of prototype by Vacuum casting:

       Although the vacuum casting of the prototype has so many shortcomings, but its price is cheap，It usually costs several hundred yuan to adopt CNC machining to produced the prototype, and only several dozens yuan to use the vacuum casting.So projects with limited budgets can be processed this way.

   To sum up, the disadvantage of vacuum casting has shrink, deformation, poor performance, And the advantage is cheap.