The main manifestations of gel deficiency in silica gel moulded products are loose surface (all or part), flax surface or void. Causes and prevention methods:

(1) Reasons: insufficient feeding

Countermeasure: In order to ensure that every hole product does not lack glue, the amount of material used should be determined accurately, and the amount of material added should be reflected in the process documents.

(2) Reasons: insufficient pressure

Countermeasure: Adhesive content can not be filled with cavity, so pressure should be increased appropriately.

(3) Reasons: The fluidity of rubber is too poor.

Countermeasure: The compound formula can be adjusted to increase plasticity when the product performance permits. Adding pressure properly or spraying a layer of zinc stearate and silicone oil on the surface of the die.

(4) Reasons: the mould temperature is too high, the rubber part burns, and the fluidity decreases.

Countermeasure: Mould temperature should be reduced appropriately, but not too much. Otherwise, the mould temperature can not rise to vulcanization temperature within the prescribed time and the whole mould compound will be scrapped. Silicone rubber can be loaded at a lower temperature.

(5) Reasons: The burning time of rubber is too short

Countermeasure: The formula should be improved to improve the scorch resistance of the compound.

(6) Reasons: charging, too slow closing speed, causing scorch.

Countermeasure: Operating technology should be improved.

(7) Reasons: The improper placement of the blank makes it difficult for the rubber to fill the cavity.

Countermeasure: Operating technology should be improved.

(8) Reasons: Irrational die structure

Countermeasure: The unreasonable mold will also make the rubber not easy to fill the cavity. For example, for long and narrow products, it should be convenient for the length direction of products to be perpendicular to the direction of pressure.

(9) Reason: Pressure is too fast

Countermeasure: The compound is extruded out of the die before it fills the die cavity, so that the flying edge is thicker and the product is short of material. The pressure speed should be slowed down. It is the compound that flows slowly into the die cavity under pressure.