How is Silicone overmolded?

Silicone overmolding is more of a layering procedure. The substrate material is really used to assemble the overmold. Although the strength of this chemical or mechanical binding is important, it can be challenging to join silicone to non-silicone materials. The substrate may need to be treated with flame, corona discharge, or plasma for very difficult material combinations. However, mechanical undercuts, protrusions, or indentations are typically used to create bonding in order to prevent part ejection from a mold.

Tools for Overmolding

But designers need to think about more than just the cost of tooling. The ratio of the flow length to the wall thickness is crucial for adhesion when sizing gates. Gates are placed in the sections of the thickest wall to reduce flow length. The mold requires deep enough vents to prevent flash since air entrapment can prevent bonding. . A sharp changeover is required between the overmold and the substrate. Additionally, the silicone overmolding must prevent thinning or feathering, which can lead to delamination.

Design factor of silicone overmolding

Since silicone overmolding improves the part’s feel and can reduce surface flaws, the texture is another crucial design factor. A part with a textured surface frequently feels softer to the touch than its durometer indicates. Additionally, textured surfaces offer better part releases than smooth ones. With injection molded parts, a wide range of textures are feasible, and designers can even include pictures or logos to promote a brand or identify a particular product.

Methods for silicone overmolding

Insert molding or multi-shot molding are two methods for silicone overmolding. The substrate and overmold are the first two material shots in double-shot molding. Two distinct resins are fired into a single injection molding tool by a press with multiple barrels. Although double-shot molding is more suitable for higher volumes due to the more expensive molds and equipment, the entire operation only requires one machine in a continuous process.

Advantages of silicone overmolding

Silicone overmolding has benefits, such as silicone being a low-cost material from which unique composite goods can be made in conjunction with silicone tubing, metal, thermoplastic, and liquid silicone rubber components. With its suitability for medium-sized production runs, it also does away with the risk and expense of a secondary assembly. It has more application-specific design flexibility.

Benefits and Applications of Silicone Rubber

The medical, aerospace, automotive, electronics, and many more industries all use silicone rubber as a crucial sealing material. Silicone rubber is frequently coveted for a number of applications because of its numerous exceptional and ideal properties. Along with its ability to withstand extremes of temperature, silicone is also resistant to a wide range of substances, including acids, bases, chemicals, water, oil, and fungi. The fact that this rubber is non-toxic despite having all these durable qualities makes it a reliable sealing material for both consumer goods and medical equipment.