Silicone Molds&Vacuum Casting

Silicone Molds&Vacuum Casting



Vacuum Casting Process

Vacuum Casting components can be used in applications from automotive pipes, digital products covers to electronic appliance frames. All possible without the need for hard steel tooling. The vacuum casting process involves encapsulating a master model in liquid silicone rubber. By this, a silicone mold came into form from the liquid rubber with an exact simulating cavity in its heart. Till the mold becomes stable in terms of shape, chemical and physical properties, castable will be injected into the cavity. After complete curing, the mold is cut open and the component shows itself. One mold can duplicate 20 to 30 components on average. In this analogy, once we get enough optimal silicone molds, low volume production won’t be a problem.

Silicone Molds

Silicone molds are universally used in vacuum casting manufacturing. Silicone molds are featured by high tenacity and often used to make plastic parts with complicate structures, intricate surface and stable measurement. They are extremely ideal for performing low volume production. 

By reviewing vacuum casting process, we learn that silicone mold serves as a bridge between the original master model and the end products. The basis of turning out highly simulated parts is to ensure that their silicone molds are produced and preserved in perfect condition. Thus low volume production can be realized. But occasionally we may come across a few troubles. For example, there are bubbles. Here let’s see a few FAQ about silicone molds. 

item

questions

answers/causes

resolution

1

why doesn't silicone mold vulcanize?

1)curing agent is too much or too little

stick to fixed proportion

 

 

2)curing agent & silicone gel not fully mixed

stir the mixture evenly

 

 

3)ambient temperature too low

increase temperature to not lower than 20

 

 

4)silicone gel has expired

silicone gel shouldn't be left in idle longer than 3 months

2

why mold and prototype glued together?

if model is made of pottery, glass or stone,they are likely to be glued

brushing prototype with detergent

3

why bubbles on the surface of mold?

1)air isn't totally squeezed out

vacuumize the mold till bubbles disappear

 

 

2)air leaks in if there are leaks on supporters

plug the leaks with putty

 

 

3)air lingers if there are condensate water or excess release agent on prototype

dry the prototype

4

why silicone mold's lifespan is reduced?

1)mold isn't heat to proper temperature

preheat mold to 60~70, then pour in resins

 

 

2)mold is constantly used without a break

reduce frequency

 

 

3)either resin isn't correct, causing too much heat

change to proper resin

 

 

4)resins not fully mixed or catalyst or additives in false dosage

adjust to right dosage

By learning the previous FAQ, we grasp how to make a good silicone mold. The quality of the silicone mold dictates the quality the part, and multiple silicone molds reproduce multiple parts simultaneously. As a result, a low volume production of high quality can be obtained in a short period. 

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