Silicone Rubber Keyboard Compression Molding vs Injection Molding

There are some methods to make silicone rubber keyboard: compression molding, liquid injection molding(LIM), insert molding, transfer molding.

Customer choose the most suitable method according to the silicone keyboard design or requirements.

We will look at two main methods of silicone keyboard molding: compression molding(HCR), and Liquid Injection Molding (LIM).

Silicone keyboard compression molding is the most common method of molding silicone rubber keyboard.The preheated silicone material is placed into an open heating mold cavity.Then close the mold and apply pressure, melt the raw materials under the set temperature and pressure generated by the press, so as to fill the cavity of the mold with the material, and get the desired rubber keyboard shape.

Silicone keyboard compression molding structure: two layer plate mold and three payer plate mold.

• Two layer plate silicone keyboard compression molding.

Note:Silicone Keyboard Design Guideline & Silicone Keyboard Compression Molding Design Guide

• Three payer plate silicone button compression molding.

Some tips of silicone keyboard compression molding manufacturing process.

• When silicone keyboard compression molding, after high pressure, because of the elastomer has the cohesion can not be eliminated, silicone rubber in the molding of the demoulding, will often produce unstable contraction (shrinkage rate is different because of the different types of silicone).It must be ease stability after a period of time.Therefore, at the beginning of the design of the silicone keyboard, no matter the formula or mold, it is necessary to carefully calculate with comprehensive consideration, otherwise the size of the silicone keyboard is easy to be unstable.

• Silicone keyboard with key webbing design, when design the mold, we should take into account the actuation force.Key webbing thickness is the key to affect the silicone keyboard actuation force.

Silicone keyboard with high requirement may choose liquid silicone injection molding.

Silicone keyboard liquid silicone injection molding is another molding method to produce silicone keyboard.

Liquid Injection molding is divided into A part and B part . The ratio of the two is 1:1 controlled by quantitative device, and then it is fully mixed through a Static Mixer.

The liquid silicone material from the static mixer flows to the injection unit. The LSR material is then injected into the mold cavity through a runner and gate system where it is held in the mold under high pressure and elevated temperature until material is cured (rubber is vulcanized). The cycle time is established to reach an optimal level of cure. At the end of the cycle, the parts are removed or ejected from the cavities and the next cycle begins.

Silicone keyboard liquid injection molding structure is much complicated.

Liquid Silicone Rubber Keyboard Printing Manufacturing Process

Silicone Keyboard Compression Molding VS Silicone keyboard Injection Molding-Advantages

Silicone keyboard compression molding advantages

• Cost effective rubber tooling

• Maximized chamber count

• Fast-prototyping and mass production

• Economical process for medium precision

• The only way to produce silicone products at Marble Colors

Silicone Keyboard liquid injection molding advantages

• High purity and cleaness of material

• Higher precision with mini parting, size tolerance can less +/-0.05mm.

• High efficiency with shorter cycle time.

• Less labor force and energy saving.Few and less rubber flashing.

• Longer keylife time.