When making silicone mold with mold silica gel, it is necessary to mix and stir the liquid mold silica gel with curing agent/catalyst according to a certain ratio. These three steps are essential links, which are also the major factors that contribute to uneven curing of mold silica gel.
1. In the process of mixing mold silica gel with curing agent and stirring, uneven and insufficient stirring will also lead to uneven curing of mold silica gel, especially the bottom and wall of the container are most easily overlooked during stirring, so this part of liquid should be hung down for stirring. Also, the stirring time should not be too short.
2. The ratio of mold silica gel to curing agent is abnormal, which will lead to wrong ratio by estimation or feeling. If the amount of curing agent is small, it will not only lead to slow curing of mold silica gel, but also lead to uneven curing in severe cases.
3. Non-uniform curing of silica gel in addition molding die is a common problem, which mainly lies in the problems of operation links. For example, the mold opener has smoking behavior during operation, and the substances contained in smoke lead to non-curing of silica gel in addition molding die. The silica gel of the additive mold is sensitive to water, nitrogen, phosphorus, sulfur, organic tin or heavy metal elements, and once the substances containing these elements come into contact, uneven curing will occur.
The above three situations will lead to uneven curing of silicone rubber in the mold, which will eventually lead to scrapping of the mold, wasting both time and materials. In order to avoid non-curing, attention should be paid to the details when operating the silica gel to open the mold.