A form of plastic injection molding, insert molding is the process of molding or forming plastic parts around other, non-plastic parts (inserts). Inserts are commonly simple metal objects, such as bushings or surgical tubes, but more complex devices, such as motors or batteries, can be used as well. In some instances, non-metal materials are used as insert components.
In general, insert molding is a highly efficient process that is very flexible and customizable. A number of plastic materials can be used, including ABS, nylon, polypropylene, and polystyrene, as well as medical grade thermoplastics.
Insert Molding Process
Insert molding is performed using advanced, high-tech molding machines specifically designed for this process. It requires extremely tight tolerances to ensure that the plastic parts are formed properly—even a sub-millimeter misalignment can cause the entire process to fail. Similarly, the insert components must also be dimensionally perfect to ensure the proper construction and performance of the finished product.
The first step of the process is creating a custom mold to hold the insert components; these components are then loaded into the mold. Then, this mold is loaded into the injection molding machine. Molten plastic then fills the mold, and, upon cooling, the mold is opened and the completed product is removed. Additional secondary processes may be performed, including die cutting, bonding, circuit testing, and others.
Insert Molded Medical Components
The versatility of insert molding makes it popular for creating a broad range of devices. It is especially useful for the medical industry, where it is used to produce everything from surgical tools and handle assemblies to cannulas, implantable devices, and more. Insert molding and subsequent packaging of medical devices is often performed in cleanroom environments to ensure cleanliness.
In addition to its high precision and the flexibility of the design process, insert molding also offers a number of other benefits for medical device OEMs. These include reduced component size and weight, reduced assembly and labor costs, and increased part reliability thanks to the inherently secure bond between inserts and plastic materials.
• Stack Plastics – “Insert Molding” http://www.stackplastics.com/insert-molding
• Plastipedia – “Insert Moulding” http://www.bpf.co.uk/Plastipedia/Processes/Insert_Moulding.aspx