1. There may be insufficient exhaust. After the silicone rubber raw material is placed in the forming mold, a lot of air will be brought in at the moment of mold closing, and the air cannot be integrated with the silicone rubber raw material. If these air are not discharged, bubbles will be generated on the surface of the silicone rubber key after forming.

2. The vulcanization temperature is too low. The vulcanization temperature is an important parameter during silicone rubber molding. Usually, silicone products are set at 160 ~ 200 degrees Celsius. However, sometimes the mold is not heated in the vulcanizer for a long time due to too long operation time outside the mold or other reasons, resulting in the low temperature of silicone molding mold and the vulcanization temperature of silicone. At this time, the product bubbles after molding will be caused. In this regard, we only need to raise the forming temperature, or open the empty mold into the machine to warm up for a period of time in operation to solve the problem.

3. If the vulcanization temperature is too high, too low vulcanization temperature will cause silicone rubber forming bubbles. In fact, in many cases, too high molding temperature will also cause silicone rubber forming bubbles. Because when the molding temperature is too high, the silicone rubber raw material on the surface has begun to form in the process of clamping and pressurization. At this time, the air has been trapped in it and it is difficult to discharge, so it will cause forming bubbles. For this reason, just reduce the molding temperature appropriately.

4. The vulcanization time is too short. Like the vulcanization temperature, the vulcanization time is also one of the important parameters of silicone rubber molding. The length of vulcanization time determines whether the silicone rubber can be completely vulcanized. If the vulcanization time is too short, it will not only make the silicone rubber soft after molding, but also cause surface bubbles. In case of such defects, the vulcanization time of silicone rubber can be appropriately prolonged.

5. The unreasonable structure of the mold and the unreasonable design of the silicone rubber forming mold will also cause bubbles in silicone rubber forming. For example, the arrangement mode, zoning mode, mold parting mode and the design of mold size in the mold will cause bad bubbles, but the cost of opening a set of mold is very high and it is not easy to modify. If silicone rubber forming bubbles are caused by the structure of the mold, So, we usually try to solve it from the above-mentioned points.