What is the molding vulcanization process and what details of the molding vulcanization process should be noted

The molding vulcanization process is the most commonly used process for preparing silicone rubber products. Its preparation method is simple, the product quality is good, and it is the most convenient and fastest process in batch production.

1. Molding vulcanization process - molding machine pressure

It refers to the set pressure of the molding vulcanizer. Through the pressure gauge and computer control, sufficient pressure can close the mold, the rubber can be completely pressed into the mold, and the vulcanization of the rubber can be ended. A small amount of water will be generated to generate bubbles, and the product bubbles can be controlled by exhaust. The rubber material has high hardness, poor flow, high selection pressure, high pressure, easy to extrude the die blade, the pressure is related to the shape and size of the die, and the pressure should also be reduced accordingly when the die size is small, so as to prevent the deformation of the die and vulcanizer plate. When adjusting the pressure of the vulcanizer, the maximum pressure of the vulcanizer shall not exceed the maximum pressure of the vulcanizer, otherwise the machine will be damaged. The empty die is not pressurized (except for injection mold), which is an effective measure to protect the mold blade and extend the life of the mold.

2. Molding vulcanization process - temperature control of the machine

Molding temperature: when the formula is fixed, the temperature is the basis of vulcanization. If the temperature is not enough, the rubber cannot react; If the temperature is too high, the product will be brittle and deformed; Generally, the silicone rubber is less than 170 degrees, and the curing speed is slow, so the time must be extended; The temperature is higher than 180 ° C, the curing speed is fast, and the output is high, but it is easy to produce mold dirt, luster, product deformation, size reduction, thickness exceeding the standard, hair edge brittleness, etc.

3. Molding vulcanization process - control molding vulcanization time

Time is the most important process for silicone product manufacturers, and the length of vulcanization time directly affects the quality of products. Short curing time, immature products, large deformation, easy whitening, and products are not durable; If the time is too long, the product will produce excessive sulfur, and the strength and hardness will become worse, leading to brittleness or surface adhesion. The relationship between temperature and time must be determined according to the product thickness and rubber type. Thick products must be vulcanized for a long time at low temperature. If the time is not enough after the mold is released, the product is not cooked and stuck to the mold, so it is difficult to clean the mold and the mold. It should be reshaped and vulcanized. Basically, the material can stick down. One of the biggest problems of molding is that employees adjust their machines, resulting in waste of products.

4. Molding vulcanization process - operation speed

It refers to the operating speed of sulfur chemical glue and products. Rubber vulcanization is a chemical reaction. Rubber materials are vulcanized from the hot mold. The first mock examination is a porous product. The shorter the time, the better. Put the glue on the mold and close it immediately. Otherwise, abnormalities such as mold dirt, hot mold, burr thickness and deformation will easily occur. When using the product, it is easy to blow the product with pneumatic assistance, but it will reduce the temperature of the mold. If you are not skilled in operation, it is most likely that the mold temperature is getting lower and lower, leading to unfamiliar products, and you still need to adhere to the mold. Novice is most likely to have this problem. In the production of smooth rubber sheet, the speed of glue application, the speed of mold sealing and the opening of mold have the most obvious influence on the quality of smooth surface. Why do some products have strict appearance requirements and choose the hanging operation? Here is one of the main principles!

5. Molding and vulcanization process - product placement

It refers to the shape of the preform, which can be a long bar, a small square, or a circle. The thickness, length and width of the compound must be close to the product. The closer the shape is to the product shape, the shorter the flow time in the mold, the shorter the flow distance, and the thinner the wool edge, the less glue is used, and the higher the product qualification rate. "-

6. Molding vulcanization process - weight of compound

The weight of the compound must be greater than the weight of the product, otherwise there will be a shortage of glue. "But the more glue, the thicker the wool edge of the product, and the larger the size. The weight of the compound is directly related to the shape of the compound. How to use the least amount of glue and produce it in the most reasonable shape without lack of glue is a reflection of the molding personnel's technical level. The weight of the glue is enough, but the length is longer than the mold, and there will also be a lack of glue. The shape and weight of the glue are appropriate, but if you put it down, There will be a thin side and a thick side, and in serious cases, there will be a lack of glue and hair thickness on one side. The shape and total weight of the rubber compound are appropriate, but the shear thickness is uneven and the filling rubber is uneven, which will also lead to the lack of rubber. When there is insufficient glue in the product, do not be anxious to aggravate the glue. First take the complete mold with burrs, check the weight of the product, and then check whether the thickness of the product is uniform, and finally decide whether to add the glue. The technical content and experience of the forming foreman are very important!