manual mold silicone rubber

Manual mold silicone rubber is mainly applicable to manual mold design, PVC plastic molds, cement product molds, melting point alloy molds, alloy toy craftworks, plastic toy craftworks, gifts and stationery, large statues, duplication of cultural relics, shoe sole mold fabrication, pad printing positioning, shock resistance for electronic equipments, etc.

Manual mold silicon rubber features with the resistance to deformation, good tensile strength as well as low shrinkage, and time of reproduction determined on the basis of customers.

1 Good elasticity  

2 Non-deformation

3 Heat resistance 

4 Low shrinkage

HY-528# is applicable to make molds of smaller products and the production will be 2-3 pieces.

HY-540# compared to other two types, for its moderate hardness and better quality & performance, its production will be 20-30 pieces.

HY-570# is applicable to large size products duplications and Electronic equipment antivibration.

 Firstly process and prepare the model mold or the product to be duplicated, take certain amount of the silicon rubber, add 2-3% solid curing agent, and mix evenly and they are ready for use. One pair of mold can be solidified and formed in 2-3 hours.

(Note: our company does not recommend you to add silicon oil. If a special soft silicon mold or fine detailed and complex patterns products are required, 5%-10% silicon oil can be added to soften the mold for easy demolding.)

To handle this situation depends on different cases. Under the condition of an available vacuum pumping machine, mix the silicon rubber and curing agent evenly and then take it to vacuum chamber to deair. If without a vacuum pumping machine, reduce the amount of the curing agent properly. For example, change the mixing ratio of the silicon rubber and the curing agent from former 4% to 1%-2%. In this way, the pre-crosslinking time of silicon rubber will slow down, so the air in the mold will be eliminated gradually to reduce the air bubbles.

The reasons why the phenomenon arises are as follows:

incorrect mixing proportion of the silicone rubber  and the curing agent due to unqualified weighing;

uneven mixing of the silicone rubber  and the curing agent, which may cause material wasting , and we should avoid it .

It arises because we didn't handle the model mold (product mold) properly. Before mold making, the model mold has to be sanded and polished, and cleaned carefully concerning the master mold with a coarse surface or to make complex molds. and then brushing a layer of release agent evenly. General release agents include Vaseline, detergent, liquid paraffin, etc. The release agents can be selected according to the different textures of various model molds.

The solution depends on the size of the product. In principle, the size of the product should be in direct proportion to the hardness of the silicone rubber. Regarding small or very fine detailed products, soft silicone  with hardness of 10-20 shore A is required for easier demould without damaging the lines of the fine products. Regarding large products, such as products with size above 50 cm, silicone rubber with hardness of 40-50 shore A  is required for non-deformation. Regarding large but fine products, silicone rubber with hardness of about 30 shore A can be used for mold making (the method is to brush a layer silicone rubber  and then paste a layer of glass fiber cloth and brush another silicone rubber), the outer mold can be made of gypsum, fiberglass reinforced plastics (unsaturated resin plus glass fiber cloth) for preventing the products from deforming.
 

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