What is silicone compression molding production?
The uncured silicone rubber pieces placed between two halves of a pre-heated tool mold. The mold is then closed under an overall pressure from vulcanizer molding machine. The pressure ensures the material forced into all area of the mold cavity, making it heated by conduction from the mold surface, and cured to the shape of the cavity. The shaped silicone components together with excess material which we called flash will be removed or demolded by hands then.
Below is the details for each stage of silicone molding production.
Silicone Raw Material Selection
The silicone molding production process begins with silicone raw material selection. Silicone rubber material are formulated to meet different application needs, so they are divided into Different Options. Based on product structure/ application needs and specific approval requirement, the most feasible material will be selected.
Silicone Material Mix and Mill
Silicone raw material will be mixed and milled before compression molding. Color pigment, vulcanizing agent, etc will be added to silicone material, making them fully mixed and milled by rollers. Adequate mixing is a must for curing of silicone during molding production.
Cutting /Blanking
Once mixed the silicone rubber compound will be cut into specific thickness and width by cutting machine, then cutting into pieces with appropriate size and weight according to the product weight.
Place The Silicone Material into Mold
The precisely cut material slabs will be carefully placed into each cavity of the tool mold to ensure enough silicone materials fill into the cavities. Then we go on with vulcanizing molding production.
Silicone Vulcanizing Molding Production
Silicone material will be fully cured under high temperature and pressure from vulcanizing molding machine, then come out well shaped.
Demolding
The shaped silicone components together with excess material which we called flash will be removed or demolded by hands then.
Deflash
Silicone Flash – Is a thin flap of material at the parting line where the mold splits. Due to the low viscosity of silicone material and high molding pressure during heating and curing, The pressurized silicone material will flow to every spaces of tool mold. Flash can be minimized with favorable designs and better tooling and accurate material weight during vulcanizer molding production. Flash will be removed mainly by hands, cryogenics deflashing can also be applicated for some cases.
Note that on all silicone parts, there will always be a flash line with a small amount of silicone flash (less than 0.3mm) remaining, we call it parting line. For some products which have value much on outlook, the parting line may affact, so please inform us in advance, our engineer will design the mold layout in a better way during programming.