What should be noted when producing liquid silicone molds and liquid silicone products?
Many silicone mold manufacturers often encounter some problems when manufacturing liquid silicone molds or producing liquid silicone products. In general, the structure of liquid silicone molds is somewhat similar to that of thermoplastic molds, but there are also many significant differences.
 For example, the viscosity of liquid silicone product materials is generally low, so the filling time is short, even under low injection pressure.
 In order to avoid air retention in the mold, a good exhaust device must be designed in the liquid silicone mold.

In addition, liquid silicone does not shrink in the mold like thermoplastic compounds. They tend to expand when heated and do not shrink slightly as expected, so their products will not remain on the convex surface of the mold as expected and difficult to demold.
 Two points should be noted when producing liquid silicone molds:
1. Shrinkage rate


Although liquid silicone does not shrink during the molding process, it typically shrinks by 2.5-3% after demolding and cooling.
 The accuracy of shrinkage depends to some extent on the formula of the material.
 However, from the perspective of the mold, shrinkage may be affected by several factors, including the temperature of the mold, the temperature of the material during demolding, the pressure inside the mold cavity, and so on.


The position of the injection point is also worth considering, as the contraction in the direction of the composite flow is usually greater than the contraction perpendicular to the direction of the compound.
 The size and appearance shape of the product also have a certain impact on its shrinkage, and thicker products generally have a smaller shrinkage rate.

2. Molding line
The first step in designing a silicone liquid injection mold is to determine the position of the mold closing line.
 The exhaust design is mainly achieved through grooves located on the parting surface, which must be located in the area where the injected liquid silicone flows towards the final direction, thus avoiding the formation of bubbles during the molding process and reducing the strength loss of the adhesive joint.

Due to the low viscosity of liquid silicone, it is necessary to design the mold line accurately to prevent raw material overflow.
 Nevertheless, it is common to see molding lines on products (which is inevitable, as liquid silicon bonding molding lines are much thinner).
 Liquid silicone molds are affected by the geometric dimensions and parting surface position of the product.
 A slightly chamfered liquid silicone product design helps ensure consistent affinity between the product and the required other half of the mold cavity.

Pay attention to the above two points during the production of liquid silicone products. We believe that the silicone mold products you make will be qualified and meet the factory standards.

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