Rubber mold is one of the simplest methods in the rapid mold, generally using silicone to reproduce the RP prototype, but the life is very short, only about 10-30 pieces! It has good elasticity and replication performance, the silicone rubber copy mold can be used without considering the inclination of the drawing die, will not affect the dimensional accuracy, there is good segmentation, without dividing the upper and lower molds can be directly poured as a whole. Then cut along the predetermined parting line and take out the master die!
Room temperature vulcanized silicone rubber is divided into two types of addition molding and condensation:
The raw material and formula are made of special mould silicone rubber, which is sold in A double package, component A is the rubber material, component B is the catalyst. When preparing, it is necessary to consider the room temperature, the strength and hardness of the mold, so as to determine the weight of the AB component.
When the room temperature is 20-25 degrees, A: B= 100:1.5. When the chamber is low (but not lower than 10 degrees), 0.1-0.3 parts of component B should be appropriately increased. If the room temperature is higher, group B is reduced by 0.1-0.3 portions. The specific method is to determine the total amount according to the volume of the mold, and then weigh the A and B components accurately according to the proportion, and then stir evenly in the vessel.
Molding: The prepared material is poured into the clean material to be imitated. In order to save materials, a thinner mold can also be painted in batches. In order to increase the tension of the mold can paste gauze. It can be cured into an elastomer in 2 hours at a room temperature of 20 degrees, and can be used a day later.


Silicone rubber mold production precautions:
1, component B is a catalyst, easy to be hydrolyzed by moisture, so the lid should be tightly covered after use.
2, A, B group once mixed, chemical reaction; Immediately start, the viscosity gradually rises, can not be suspended, in order to avoid waste, should be based on the amount, with the use, after the good should be used immediately, can not be delayed.
3, the mix ratio of group A and B is related to the speed of chemical reaction and the performance of the mold. The more component B, the faster the reaction, the higher the strength and hardness of the product, but the toughness will be reduced. Therefore, the weighing requires precision.
4, before preparation, component A should be stirred up and down evenly, and then weighed.
5, the pouring method is suitable for the relief class, and the brushing method is suitable for the production of three-dimensional molds. The mold of casting relief should first be made with a border that is 4-6CM longer and wider than the original length and width. The border should be flat and the inside should be smooth. Place the frame on a clean glass plate when pouring, and then place the original in the frame, leaving a gap of 2-3CM on each side.