Liquid silicone mold production process and precautions

1. The selection of mold opening form and mold line is very important. Firstly, it is for the convenience of mold removal. Secondly, the mold line should be selected in a way that does not affect the overall effect of the product. silicone rubber mold liquid Thirdly, it does not affect the quality of the product. For example, the mold line position of the waterscape series products is too high,silicone rubber mold making materials  and there are too many materials required to seal the mold line, which makes it easy for the product to crack; The fourth is to reduce process operations, such as opening half of the mold.
2. To prevent the silicone from flowing around, fix the mold seeds in a regular range with wooden blocks or wooden boards. When opening the mold, separate the first part with wooden boards and oil mud. It is required that there is no gap between the oil mud and the mold seeds, and the surface of the oil mud is smooth and flat.
3. Next, apply Vaseline or spray release agent on the mold (which can also be replaced by detergent or soapy water). Smooth products require a clean cotton cloth dipped in Vaseline and evenly applied to the mold. Hold for 30 minutes until the mold fully absorbs Vaseline, and then wipe the surface of the mold with a clean cotton cloth to ensure a bright surface; Products with texture only need to be evenly coated with Vaseline to adjust the silicone according to the formula. When mixing silicone, stirring should be carried out in an irregular direction to fully mix the curing agent and silicone, and minimize the mixing of air into the adhesive. It is best to vacuum the smooth product once when applying the first layer of adhesive, and the vacuum degree should be maintained for 7-8 seconds at -0.1Mpa.
4. After the silicone is prepared, the mold should be made in a timely manner. Pour silicone from the highest part of the mold and let it flow naturally. Use an oil painting brush to brush any areas that do not flow properly; If it is a mold, silicone should not only fill the entire product but also be evenly brushed on the adhesive; Each product should be coated with at least three layers of silicone, with a thickness of 1mm for each layer; After brushing the first layer, when the silicone is semi dry, apply a layer of gauze on its surface to enhance the hardness and tear resistance of the silicone; During the process of brushing silicone, it is required that each layer be cured before brushing another layer; The number of layers to apply silicone and the layer to apply gauze should be operated according to the actual situation. The thickness of the silicone part of the entire mold should be controlled within 3-4mm according to the requirements of different product sizes, and the width should not be greater than the product width of 60mm. Usually, the starting solidification time of the silicone is about 20 minutes (the operation time and solidification time of products from different manufacturers may vary).

The specific operation is as follows:
1) Wash and air dry the mother mold for smooth treatment (it can be applied with a layer of release wax or a layer of release agent);
2) Pour 500-1000 grams of liquid mold silicone rubber (mold silicone, mold rubber, silicone rubber, silicone rubber, liquid silicone) into a plastic basin for later use;
3) Pour the curing agent into a plastic bowl in a weight ratio (usually 1.5-2.5%, and the mixing ratio of liquid silicone provided by each manufacturer is also different) and mix thoroughly;
4) After mixing mold silicone rubber (mold silicone, mold rubber, silicone rubber, silicone rubber, liquid silicone) with curing agent, the reaction occurs at room temperature and releases low molecular alcohol. To separate the alcohol molecules from the colloid, vacuum and bubble them for 1-3 minutes under negative pressure in a vacuum machine. It can also be done without the use of equipment (mainly depending on the mold technician's operating experience);
5) It is advisable to adhere to the principle of simultaneous curing of the inner, middle, and outer layers of the multi-layer brushing film mold. When the amount of curing agent is relatively small, the reaction time is prolonged, the reaction is sufficient, and the colloid is good. Therefore, it is best to use less curing agent inside and more curing agent outside. When applying, wait for the first layer (inner layer) to dry before applying the second layer. The operation time is 30-50 minutes, and the mold removal time is 3-4 hours. The curing time is 24 hours. It is best to add a mold cloth after applying the first and second layers, which can greatly improve the service life of the mold (but glass fiber cloth should not be used, otherwise it may cause layering and cause the entire mold to be scrapped);
6) Stereoscopic injection mold, usually cured in 3-4 hours;
7) After the completion of the soft mold production, gypsum or fiberglass outerwear (outer coat or gel coat) should also be made to support the silicone soft mold;

5. Operating precautions:
1) Mold line selection: Select a location that does not affect the appearance of the product; Select a location that is easy to process after grouting; Choose a location where the mold itself is easy to remove; Choose a location where the product is not easily deformed;
2) Do not blindly increase the amount of curing agent to catch up with production progress, otherwise it will greatly reduce the service life of silicone molds;