What methods do you recommend to help eliminate silicone being stuck in the tool?

1 Reply

Question: I recently completed a project and took it into production.  The production has produced less than stellar yield.  The main issue is the silicone sticking to the tool.  The tooling is fairly complex with some thin material undercuts.  However, my question is: What methods do you recommend or material formulation to help eliminate material (silicone) being stuck in the tool?

Answer: Sticking can be reduced by changing materials, changing the tool surface, adding a release, or seasoning the tool. Changing 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 silicones. 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 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.

If you have any other questions, please comment or ask me directly at mbont@albright1.com.

 

  • Sean Dickson

    The first answer is all true; but there are some other things you need to evaluate. Is the silicone peroxide or platinum cured? Either system will rely on reaching the optimum cure so that the part will properly release. In addition, depending on the cure system used, you must be careful on what release agents and mold coatings you use as they could deplete the cure–or potentially completely eradicate it. Next, are you using a vacuum mold or not? Again, this can make a difference. What injection pressure, mold pressure, and platen temperatures are you using? Once you identify these things, you will likely be able to determine the process best suited for the part and then your silicone supplier can help you determine what mechanical properties will enhance the process.