In this article, we will mentioned two methods of manufacturing silicone & plastic molded products: Overmolding & Double Shot Molding, which are viable manufacturing processes that offer several advantages for many plastic manufacturers. Both processes can be difficult to master since they require adherence to the very tightest of tolerances. Overmolding is done with ordinary injection molding machine, then take out the first molding product, and then put into another injection molding machine again. While Double Shot Molding is done by a two-color injection molding machine, which can be molded once, and can have two kinds of color effect and different material composition. Below, we discuss the differences and advantages between double shot molding and overmolding.

Overmolding

Overmolding is to make the plastic parts, such as sheet, tube and plate, etc., formed with silicone rubber material to be one piece. Generally, the substrate material (the first piece that will be bonded with other materials) is placed into an injection molding tool, then the overmold material is shot into or around the substrate. When the overmold materials solidify, the two materials become joined together as a single part.

Overmolding can be added to change the surface of a piece or product by adding texture, color, and incorporating necessary functionality components. Other advantages include:

• Enhanced design flexibility and multi-material components.

• Reduced secondary operations; assembly and labor costs.

• Improved part strength and structure.

Our company has rich experience in overmolding products, like overmolding silicone keypad, overmolding rubber keyboard, overmolding membrane valve and overmolding for medical plastic parts, etc.

Double Shot Molding

Double Shot Molding is the operation method for molding the same kinds of plastic with two different colors through two cylinders at the same time or successively through the same nozzle. By using two injection molding machines or two color injection molding machines, various products with mixed color patterns can be produced, as well as products with obvious color separation.

Double shot molding is an ideal process for complex, multi-material, and multi-colored plastic products; specifically in high-volume production scenarios. Other advantages include:                                                                                                                         

• Lower unit cost.                                                                                                                                                                             

• Reduced cost and waste associated with assembly defects.                                                                                           

• Enhanced product quality.