Question: I recently completed a silicone molding project and took it into production. The production has produced less than stellar yield. The main issue is the medical liquid silicone sticking to the tool. The tooling is fairly complex with some thin material undercuts. However, my question is: What methods for silicone molding do you recommend or material formulation to help eliminate material (silicone) being stuck in the tool?
Answer: Sticking can be reduced by changing liquid silicone molding materials, changing the tool surface, adding a release, or seasoning the tool. Changing medical silicone molding material with regard to the issue may improve release. For example, undercuts may be dealt with by finding a softer material with higher tear strength. Rougher surface finishes tend to promote less sticking compared to highly polished tools for liquid silicone molding. Alternatively some plating companies offer nonstick coatings that for some materials may be effective in improving release. Some molds will improve with increased number of cycles. The quick and easy option may be to use a release agent which many suppliers offer. Some releases may be specified for your liquid silicone material or for general use and Soap may be an alternative for those trying to control contamination risks. Releases usually only last some number of cycles before the effect diminishes and some may build up and require periodic cleaning.