Silicone mold manufacturing process and common problems

January 16, 2021

Silicone mold is a special mold glue for making crafts. The characteristics of silica gel are high temperature resistance, corrosion resistance, strong tear resistance and high simulation. It is a special mold for various crafts.

Here is a brief introduction to the simple production process of silicone molds.

The choice of mold opening form and the selection of mold line are very important. First, it is convenient for mold taking. Second, the mold line should be selected without affecting the overall effect of the product. Third, it does not affect the product quality. For example, the mold line position of the water series product is too High, when the mold line is required, there are many materials, and the product cracking is easy to occur; the fourth is to reduce the process operation steps, such as opening half of the mold.

In order to prevent the flow of the silica gel, the mold is fixed in a regular range by wood or wood. When the mold is opened, the first part of the mold is separated by the wood and the sludge, and there is no gap between the sludge and the mold, and the surface of the sludge is smooth and flat. After the above work is completed, the plaster or mold is coated with Vaseline or sprayed with a release agent. The smooth product is coated with a clean cotton cloth and coated with Vaseline evenly on the mold for 30 minutes. The species is fully absorbed with Vaseline, and the surface of the mold is wiped clean with a clean cotton cloth, and the surface is required to be bright; while the product with texture is uniformly coated with Vaseline, the silica gel can be adjusted according to the formula. When the silica gel is formulated, it should be stirred in an irregular direction, so that the curing agent and the silica gel are thoroughly mixed to minimize the mixing of air into the rubber. The smooth product is preferably vacuumed when the first layer of glue is applied, and the vacuum degree is required to be maintained at -0.1 Mpa. 7-8 seconds.

After the silica gel is prepared, it should be molded in time. Pour the glue into the highest part of the mold by trickle, let it flow naturally, and use the oil brush to put it in place. If it is a piece of mold silicone, not only the whole product but also the glue should be evenly brushed. Each product is brushed at least three layers of silica gel. The thickness of each layer of silica gel is 1mm. In the process of brushing silica gel, each layer is required to be cured before brushing another layer. When brushing the third layer, add one layer to the second layer. Layer gauze to increase the strength of the silica gel. The silicone part of the whole mold is controlled to 3-4 mm according to the required thickness of the product, and the width is not more than 60 mm of the product width. The initial solidification time of the silica gel is 20 minutes.

1. Wash and dry the master mold for smoothing (can apply a layer of mold release wax or apply a mold release agent) 2. Apply 500-1000 grams of mold silicone rubber (mold silicone, mold glue, silicone rubber, silicone) Shengru plastic basin spare; 3, the hardener is weighed according to the weight ratio (usually 1.5-2.5%), then added to the container for mixing, fully stirred; 4, depending on the situation (especially the first layer) added a certain amount of silica gel Thinner. Until the mixing is uniform, usually 3-5 minutes.

5. After the mold silicone rubber (mold silicone, mold glue, silicone rubber, silica gel) is mixed with the hardener, the reaction is carried out at room temperature, and the low molecular alcohol is released. In order to remove the alcohol molecules from the colloid, it is necessary to discharge the bubbles under a negative pressure. -3 minutes. It can also be used without the aid of equipment (mainly depending on the operation experience of the molder). 6. Multi-layer brushing die should be cured at the same time as inner, middle and outer. When the amount of the curing agent is relatively small, the reaction time is lengthened, the reaction is sufficient, and the colloid is good. Therefore, the amount of the curing agent is preferably less than the inside. When the brush is applied, the first layer (the inner layer) is dried and then the second layer is brushed. The operation time is 30-50 minutes, and the demoulding time is 10-15 hours. Curing time is 24 hours. Note that after the first and second layers are applied, it is better to add the mold cloth, which can greatly improve the service life of the mold (but the glass fiber cloth can not be used, otherwise it will easily cause delamination and the whole mold will be scrapped). 7. Three-dimensional perfusion mold, generally It is good to cure in 10-15 hours.

8. After the soft mold is finished, make a plaster or FRP jacket to support the silicone soft mold. Note: 1. Mould line selection: choose the position that does not affect the appearance of the product; choose the position that is easy to process after grouting; select the mold itself is easy to dismantle The position of the mold; select the position where the product is not easily deformed. 2. Do not blindly increase the amount of hardener for the production schedule, otherwise the service life of the silicone mold will be greatly reduced.

Common problems encountered in mold silicone applications:

1. Why does the mold silicone have fewer molds?

In the process of making the mold, too much silicone oil is added, and the silicone oil destroys the molecular weight of the silica gel, so the mold will have a phenomenon of less mold turning and less durability. If you say that the product with a small product pattern is more complicated, and the mold with a high hardness is used to open the mold, there will be a phenomenon of less mold turning, because the time when the silica gel is too hard will be very brittle and easy to break. On the contrary, if you build a product and use a low-hardness silica gel to make the mold, the result will be unsatisfactory. Because the silica gel is too soft, its tensile strength and tear strength will be reduced, and the resulting mold will be deformed, so the number of overturning will be reduced. The quality of the mold glue itself is very good, the silicone is not good or bad, only suitable and not suitable. We don't want to use a silicone that is suitable for the hardness of the product to make the mold.

2. Why does the mold silicone show a burning phenomenon?

Because the unsaturated resin and the resin product are added with a peroxide curing agent, a large amount of heat is generated when the resin reacts. Generally, the curing time of the resin is 3 minutes, so it is necessary to demold the mold as soon as possible after 3 minutes to prevent the silicone mold from being prevented. Produce a phenomenon of burning.

3. Molding method and mold of mold silicone:

Slicing mold or sheet mold operation method: The vacuum-treated silica gel is applied by brushing or pouring. If you are using a stencil or a stencil, use a brushing method to apply a layer of release agent or release agent to the product or model you want to copy, then apply the silicone to the product. : Be sure to apply evenly. After waiting for 30 minutes, stick a layer of gauze or fiberglass cloth on the surface to increase the strength, then apply a second layer of silica gel. After the silica gel is dried, the outer mold can be used. Materials such as gypsum or resin.

The operation method of filling or pouring mold: filling or pouring mold, which is used for relatively smooth or simple products, is the product or model to be copied, surrounded by rubber or glass plate, and vacuumed silica gel. Pour directly into the product. After the silica gel is dried and formed, the product is taken out and the mold is formed. (Note: The perfusion mold is usually made of silica gel with softer hardness, so that the mold release is easier and will not damage the product inside the silicone mold) The above is the whole process of using and operating the mold silica gel.

4. Why does the mold silica gel appear to be dry in the stem?

Mold silicone is a kind of condensation type silica gel. It is solidified by absorbing water in the air. In the process of making silica gel, the water is evaporated and dried without any appropriate amount of water. . Solution: This phenomenon is not a product quality problem, but because there is no control of water, the storage period of the silica gel is improved, and the shelf life will last for a long time. As long as the silica gel is used, an appropriate amount of 0.05% water is added, and the mixture is evenly stirred. Can solve some situations.

5. Why does the mold silicone have a poor pull?

Because the customer in the process of making the mold, in order to reduce the viscosity of the silica gel, the silica gel is easy to handle and a large amount of silicone oil is added to the silica gel, which makes the silica gel soft, produces non-resistance, and reduces the tear strength. The phenomenon that the pulling force is deteriorated, resulting in the phenomenon that the mold is not durable, the service life is short, and the number of times of mold turning is small.

6. Why does the mold appear to be in a fuel condition?

The mold silicone itself does not oil, and oil is produced because the compound silicone oil (complex of silicone oil and white mineral oil) is added during the operation because the white mineral oil is a petrochemical product, not a silicone oil.

7. Why does the mold produce acid and alkali resistance and is not resistant to aging?

In the process of making silicone molds, we recommend that customers do not add any silicone oil. If necessary, do not add more than 5% to 10% of silicone oil. Because the excessive amount of silicone oil will destroy the molecular weight of silica gel, it is made. The mold will produce acid and alkali resistance and is not resistant to aging.

8. Why does the mold made of mold silicone have traces, streaks, and matte on the surface?

This phenomenon occurs because the product or model to be copied is not polished or polished. Because the model or the product itself is not smooth or perfect, the product or model to be copied will not be aesthetically pleasing or smooth if it has not been polished or polished. In another case, when the mold release agent is applied, even if the paint is not evenly applied, the mold is not smooth.

9. Wonderful use of mold silicone you know? ?

Mold silicone is mainly used in the toy gift industry, craft gift industry, furniture decoration and decoration industry, character reproduction, architectural decoration and decoration industry, resin crafts industry, unsaturated resin crafts industry, candle craft? Plastic toy industry,? Gift stationery industry? , gypsum craft gift industry,? Mold manufacturing industry,? Polly industrial products? , simulation of animal and plant sculpture, Buddha carving crafts and other product reproduction and mold making.

Mainly used in toys, gifts, fine patterns, for mold, infusion mold products, glass crafts, lighting, candles, character reproduction molds, large products, open film molds, reliefs, Buddha statues, craft gifts Make molds, sole models, infusion molds, and sand casting.

The specific operations of the different uses of the mold silicone are also different. To meet the requirements, it is necessary to operate according to various parameters.

Silicone Wine Cup