Production process

The selection of mold opening form and mold line is very important. First, it is convenient to take 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 product quality. For example, the mold line position of waterscape series products is too high, and there are too many materials to seal the mold line, so the product cracking is easy to occur; Fourth, reduce the process operation procedures, such as half opening the mold.

In order to prevent silica gel from flowing around, fix the mold seed in a regular range with wooden square or wooden board. When opening the sheet mold, separate the first part with wooden board and oil sludge. There is no gap between oil sludge and mold seed, and the surface of oil sludge is smooth and flat.

After the preparation of the above work, then apply Vaseline or spray release agent on the gypsum mold or mold seed. The smooth product shall be evenly coated on the mold seed with clean cotton cloth stained with Vaseline for 30 minutes to make the mold seed fully absorb Vaseline, and then wipe the surface of the mold seed with clean cotton cloth to make the surface bright; For products with texture, just apply Vaseline evenly and adjust the silica gel according to the formula. When mixing silica gel, it shall be stirred in an irregular direction to fully mix the curing agent and silica gel, and minimize the mixing of air into the glue. For smooth products, it is best to draw a vacuum when coating the first layer of glue, and the vacuum degree shall be maintained for 7-8 seconds when it is required to be -0.1mpa.

After the silica gel is prepared, the mold shall be made in time. Pour the glue solution on the highest part of the mold by trickling, and let it flow naturally. Where the flow is not in place, use an oil painting brush to put it in place. If it is a chip mold, the silicone will not only fill the whole product, but also brush evenly on the mastic. Each product shall 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 silica gel, it is required to brush another layer after each layer is cured. When brushing the third layer, a layer of gauze shall be added on the second layer to increase the strength of silica gel. The thickness of the silica gel part of the whole mold shall be controlled within 3-4mm according to the requirements of different product sizes, and the width shall not be greater than 60mm of the product width. The setting time of silica gel is 20 minutes.

1. Clean and dry the master mold for smooth treatment (a layer of release wax or a layer of release agent can be applied)

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

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

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

5. After the mold silicone rubber (mold silicone, mold glue, silicone rubber and silica gel) is mixed with the hardener, it reacts at room temperature and releases low molecular alcohol. In order to separate the alcohol molecules from the colloid, it is necessary to discharge bubbles under negative pressure for 1-3 minutes. It is also possible not to use equipment (mainly depending on the operation experience of the molder)

6. For multi-layer brushing of sheet mold, it is appropriate to follow the principle of simultaneous curing inside, middle and outside. When the amount of curing agent is relatively small, the reaction time is prolonged, the reaction is sufficient, and the colloid is good. Therefore, the amount of curing agent should be less inside and more outside. When painting, the second layer shall be painted after the first layer (inner layer) is dry. The operation time is 30-50 minutes and the formwork removal time is 10-15 hours. The curing time is 24 hours. Note that it is better to add mold cloth after brushing the first and second layers, which can greatly improve the service life of the mold (but glass fiber cloth must not be used, otherwise it is easy to cause delamination and scrap the whole mold)

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

8. After the soft mold is made, gypsum or FRP jacket shall be made to support the silica gel soft mold. Note: 1. Selection of mold line: select the position that does not affect the appearance of the product; Select the position easy to process after grouting; Select the position where the mold itself is easy to remove; Select the position where the product is not easy to deform. 2. Do not blindly increase the amount of hardener in order to catch up with the production progress, otherwise the service life of silica gel mold will be greatly reduced.