What are the procedures of hot compression molding silicone production?


In our life, there are silicone molding products most common, but how are they made? Before a finished silicone molding product, there are 12 processing must be going through.


  1. Drawing making.

First and basic work, you must have an idea of what kind of product you need in what type. It means you need to finish a drawing of the product that you would like us to make for you.


  1. Molding Making

The molds for the product must be made according to the sizes, and structures specified in the customization drawing.


  1. Choose the right silicone material and durometer for production.

The silicone molding production process begins with silicone raw material selection. Silicone rubber materials are formulated to meet different application needs, so they are divided into Different Options. Choosing the right silicone material when manufacturing a new silicone product is vital for its success.

By understanding our client’s needs properly, we will recommend the best silicone material. Based on product structure/function,  application environment, performance, safety test requirements, and customer’s budget, the most feasible material will be selected.


4 . Silicone material compounding and blending

Silicone raw material itself is milk-white or transparent gum-like components with no elasticity and strength. In order to improve the characteristics of raw silicone material and to have the desired colour, silicone material will be compounded with many ingredients such as vulcanizing agent, reinforcing filler,  accelerator, colorant, etc.

Silicone compounding is the complex technology of selecting and blending silicone with other ingredients. The proper mixture is crucial to the success of silicone molding production.


  1. Cutting/Blanking

Silicone material after blending will be collected in large rolls covered with film to prevent dust or dirt. It then will be cut into slices by an automatic cut machine. The slices’ length and width will be controlled according to the silicone part’s weight to be molded. Silicone blanking makes it easier for our molding operators to weigh the material during silicone molding production.


  1. Weight and place the silicone slung onto preheated tool mold

Molding operators should be able to cut slices into small pieces and weigh them accurately, then place them quickly onto the tool mold in the right place. Material weight is crucial, as too much material will lead to silicone parts size increase, and a lack of material will cause small sizes or missing parts.

HB Silicone offers standardization training to each molding operator, all our molding staffs have at least 3 years of work experience in silicone molding production. Their years of experience allow them to solve any manufacturing problems in silicone molding, and ensure reliable and high-quality outcomes.

  1. Molding production

The hot compression molding machine produces the product with high temperature, high air pressure, and proper molding time.

  1. Demolding

When the silicone is fully cured, the vulcanizing molding machine will release the pressure automatically, tool mold will come out and open for molding operators to remove the molded silicone parts. The raw material will be placed again for the next round of vulcanization.

  1. Deflash

Silicone Flash – This 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 space of the 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 hand, 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 a value much on outlook, the parting line may affect, so please inform us in advance, our engineer will design the mold layout in a better way during programming.

  1. Quality inspection

After the molding the deflashing, all the products must be inspected by visual inspection to pick out the defective products (Blistering, Chips, Contamination, Flow Lines, Porosity, Short Moldings, etc ).

  1. Graphic or Brand Name print.

People usually like to have their customized graphic or personal Brand Name printed on the silicone products.

11. Package design

Lots of people like to have the products to pack in their customized packages.

  1. Packing

Pack the products in accordance with the customer’s request.

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