The production process of silica gel mold
Silicone mold is a fast mold in one of the most simple method, is generally used to copy the prototype with silicone mold, generally can copy 10-30 pieces or so! Silicone mold has good elasticity and replication performance, can not consider the Angle of drawing mold, will not affect the dimensional accuracy, has a good segmentation, no upper and lower mold can be directly for the whole pouring.
About the silicone mold production, the choice of the form of the mould and die line selection is very important, it is convenient to modulus, 2 it is mould line should fall in does not affect the overall effect of the product, 3 it is does not affect the product quality, such as water series product line position is too high, seal line when much of the material, production has been prone to cracking; Four is to reduce the process operation, such as opening half of the die.
In order to prevent the flow of silica gel, the mold is fixed in a regular range with wood or wood, and the first part of the mold is separated by wood and oil when the mold is opened. It is required that there is no gap between the oil and the mold, and the oil surface is smooth and smooth. After the preparation of the above work, then in plaster mold or mold on the coating of vaseline or spray on the mold release agent, smooth product requirements with clean pure cotton cloth coated with vaseline evenly on the mold, maintain 30 minutes to fully absorb the mold vaseline, and then use clean pure cotton cloth to wipe the mold surface, the surface is bright; A textured product can be prepared by evenly coating it with vaseline. Silicone mixing should be carried out according to the irregular direction of stirring, so that the curing agent and silicone fully mixed, as far as possible to reduce the air into the rubber, smooth products had better be coated with the first layer of rubber vacuum, vacuum degree requirements – 0.1 mpa when 7-8 seconds.
Silicone should be made in time after matching. Pour the glue solution on the top part of the mold in the way of drip, let it flow naturally, where the flow is not in place, use the painting brush in place, if it is a piece of mold silica gel not only fills the whole product but also brush evenly on the cement. Each product shall be coated with at least three layers of silica gel with a thickness of 1mm. In the process of brushing silica gel, each layer shall be cured before another layer is brushed. When brushing the third layer, a layer of gauze shall be added above the second layer to increase the strength of silica gel. According to the requirements of different sizes of products, the thickness of the silicone part of the whole mold should be controlled at 3-4mm, and the width should not be more than 60mm. The initial setting time of silica gel is 20 minutes.
1. Wash the origin mold, dry it, and smooth it (a layer of mold removal wax or brush the mold removal agent can be applied).
2. Put 500-1000 grams of mold silicone rubber (mold silicone, mold glue, silicone rubber, silicone) into a plastic basin for later use;
3. Weigh the hardener by weight (generally 1.5-2.5%) and add it to the container for mixing.
4. Add a certain amount of silica gel diluent as appropriate (especially the first layer). Mix well, 3 to 5 minutes.
5. Mold silicone rubber (mold silicone, mold gum, silicon rubber, silica gel) is mixed with hardener. Reaction is carried out at room temperature and low molecular alcohol is released. In order to remove the alcohol molecules from the gel, the foam should be drained for 1-3 minutes under negative pressure. Equipment can also be used without help (mainly depending on the operation experience of the mold maker)
6. Multi-layer brush sheet mold, should follow the internal, internal, external curing at the same time is appropriate. When the dosage of curing agent is relatively small, the reaction time is prolonged, the reaction is sufficient, the colloid is good, so the dosage of curing agent is better inside less outside more. Besmear when brush, wait for the first layer (inside layer) dry hind brush second layer again. The operation time is 30-50 minutes, and the mold removal time is 10-15 hours. Curing time: 24 hours. Pay attention to the coating of the first and second layers, it is better to add such as mold cloth, which can greatly improve the service life of the mold (but do not use glass fiber cloth, otherwise it is easy to cause layer and make the whole mold scrap).
7. Three-dimensional perfusion mode, usually 10-15 hours for curing.
8. After the completion of soft mold to make plaster or fiberglass jacket to support the silicone soft mold
1. Mold line selection: select the position that does not affect the appearance of the product; Select the location that is easy to process after grouting; Select the location where the mold itself can be easily removed; Select the position where the product does not deform easily
2. Do not blindly increase the amount of hardener to catch up with the production schedule, otherwise it will greatly reduce the service life of the silicone mold.