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Selection Of Mold Silicone And Selection Of Mold Line

Jun 20, 2020

The choice of mold opening form and mold line selection is very important,


   One is for the convenience of taking the mold


  Second, the mold line should be selected so as not to affect the overall effect of the product


   Third, it does not affect the quality of the product. For example, the position of the mold line of the waterscape series product is too high, and the material required for the sealing line is too much, and the product cracks are easy to appear. Fourth, the process operation process is reduced, such as opening half of the mold.


  In order to prevent the silicone from flowing around, the mold is fixed in a regular range with wood or wood. When opening the mold, the part that is first separated by wood and sludge is required. There is no gap between the sludge and the mold. The surface of the sludge is smooth and flat. After the preparation of the above work is completed, then apply petroleum jelly or spray release agent on the plaster mold or mold. For smooth products, use clean cotton cloth dipped in petroleum jelly to coat the mold uniformly, and keep the mold for 30 minutes. Fully absorb Vaseline, and then clean the surface of the mold with a clean cotton cloth, and the surface is required to be bright; and as long as the textured products are evenly coated with Vaseline, the silicone can be adjusted according to the formula. Silica gel should be stirred in an irregular direction to make the curing agent and silica gel fully mixed to minimize the mixing of air into the glue. It is best to apply a vacuum when applying the first layer of glue for smooth products. The vacuum must be maintained at -0.1Mpa 7-8 seconds.


  Mould be timely made after the silicone is equipped. Pour the glue on the highest part of the mold in a trickle to let it flow naturally. If it does not reach the place, brush it in place with a paintbrush. If it is a piece of mold silicone, it will not only fill the entire product but also brush the glue evenly. Each product should be brushed with at least three layers of silica gel. The thickness of each layer of silica gel is 1mm. In the process of brushing the silica gel, each layer is required to be cured before brushing another layer. When brushing the third layer, add one on the second layer Layer gauze to increase the strength of silicone. The thickness of the silicone part of the whole mold is controlled at 3-4mm according to the requirements of the size of the product, and the width is not greater than the product width of 60mm. The silicone gel starts to set for 20 minutes.


   1. Wash and dry the master mold for smooth treatment (you can apply a layer of mold release wax or brush the mold release agent again)


   2. Put 500-1000 grams of mold silicone rubber (mold silicone, mold glue, silicone rubber, silicone) into a plastic basin for use;


   3. Weigh the hardener according to the weight ratio (usually 1.5-2.5%), add it to the container for mixing, and stir it thoroughly;


   4. Add a certain amount of silica gel thinner as appropriate (especially the first layer). Until the mixture is uniform, generally 3-5 minutes.


5. After the mold silicone rubber (mold silicone, mold rubber, silicone rubber, silica gel) is mixed with the hardener, it will react at room temperature and release low-molecular-weight alcohol. In order to release the alcohol molecules from the colloid, the foam needs to be discharged under negative pressure. -3 minutes. There is no need to use equipment (mainly depends on the operation experience of the mold maker) 6. Multi-layer brushing molds should be cured at the same time inside, inside and outside. When the amount of curing agent is relatively small, the reaction time is longer, the reaction is sufficient, and the colloid is good. Therefore, it is best to use less curing agent and more outside. When painting, wait for the first layer (inner layer) to dry before brushing the second layer. The operation time is 30-50 minutes, and the mold removal time is 10-15 hours. Maintenance time is 24 hours. Note that it is best to add gauze after the first and second layers are painted, which can greatly improve the service life of the mold (but glass fiber cloth should not be used, otherwise it will easily cause delamination and the entire mold will be scrapped)


   7. The three-dimensional pouring mold is usually cured in 10-15 hours.


   8. After the soft mold is made, a gypsum or glass fiber reinforced plastic jacket must be made to support the silicone soft mold

Source:https://www.up-resin.com/

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