How should we solve the problem of poor bubbles in silicone buttons

Poor bubbles in silicone buttons, also known as air pockets or air marks in the industry. Silicone button bubbles appear as white bubbles or small white spots on the product after molding. When the bubbles are torn or cut open, the inside of the bubbles can be seen to be honeycomb shaped (sponge like), and the feel is soft and sticky. If bubbles are generated during the molding process of silicone buttons, it can affect the appearance of the product. If bubbles appear on some functional structures, it can affect the functionality and service life of silicone buttons. So how should we solve the problem of poor bubbles in silicone buttons?

Insufficient exhaust, when the silicone button material is placed in the molding mold, a lot of air will be introduced at the moment of mold closing, and air cannot be integrated with the silicone material. If this air is not discharged, it will cause bubbles to form on the surface of the silicone button after molding. We need to open the mold after closing and applying pressure, so that the air in the mold can be expelled. This process is called exhaust. We need to set the distance and frequency of mold opening according to different products, which is commonly known as the exhaust stroke and exhaust frequency. The exhaust stroke is usually set between 0.6~1.2cm, and the exhaust frequency is generally set between 1~3 times. There is no fixed value for the specific setting, and it needs to be repeatedly tested according to the structure and size of the product to achieve the best effect.

The vulcanization temperature is too low. The vulcanization temperature is an important parameter during the molding of silicone rubber buttons. Usually, silicone products are set at 160-200 degrees Celsius. However, sometimes due to prolonged operation outside the mold or other reasons, the mold is not heated in the vulcanizing machine for a long time, resulting in a low temperature of the silicone button molding mold and the vulcanization temperature of the silicone button, which can cause bubbles in the molded product. We only need to increase the molding temperature or heat the empty mold into the machine for a period of time before operating to solve the problem.

The vulcanization temperature is too high. As mentioned earlier, too low a vulcanization temperature can cause bubbles in the molding of silicone buttons. In fact, many times, too high a molding temperature can also cause bubbles in the molding of silicone buttons. When the molding temperature is too high, the silicone raw material on the surface has already started to form during the process of clamping and pressing, and the air is trapped inside and difficult to discharge, which can cause molding bubbles. For this reason, simply lower the molding temperature appropriately.

The vulcanization time is too short, just like the vulcanization temperature, vulcanization time is also one of the important parameters for silicone button molding. The length of vulcanization time determines whether the silicone button can be fully vulcanized. If the vulcanization time is too short, not only will the silicone button become soft after molding, but it is also more likely to cause surface bubbles. If such defects occur, the vulcanization time of the silicone button can be appropriately extended.

The structure of the mold is not reasonable, and the design of the silicone button molding mold is not very reasonable, which can also cause bubbles to form during the molding of silicone buttons. For example, the arrangement, partitioning, and mold size design of the products in the mold can cause poor bubbles. The cutting and discharging methods of the raw materials are usually set as thick as possible when formulating the cutting specifications of the raw materials. The discharging is arranged between the silicone button keys. At this time, if pressure is applied, the raw materials will flow into the bottom of the key from the side of the key and gradually fill the entire key, causing the internal air to overflow from the mold with the filling of the raw materials, resulting in poor bubbles.