There are various techniques for the injection moulding of plastic products. For example, have you heard of insert moulding and outsert moulding? In this article, we will tell you more about these manufacturing techniques: what they are used for and when to utilise each one.
What is the difference with outsert moulding?
Outsert moulding is the same technique as insert moulding, with one key difference: the volume and/or surface area of the insert is greater than that of the plastic, which means only part of the insert is covered in plastic. In other words: with outsert moulding, the plastic is injected against the insert, not around it.
The injection-moulding process for insert and outsert moulding
The injection-moulding process for insert and outsert moulding is largely the same as for “standard” injection moulding. The standard process is as follows:
An injection-moulding machine injects molten plastic pellets into a mould.
The plastic solidifies with the help of a cooling system.
The press opens and the plastic components are ejected from the mould.
The difference: with insert and outsert moulding, you first place a metal component in the mould before closing it.
What materials and facilities are needed for insert and outsert moulding?
You use the same thermoplastics for insert and outsert moulding as for regular injection moulding. Generally speaking, you can also use the same mould steel, mould structure and injection-moulding machine. In some cases, however, we may opt for the use of a vertical injection-moulding machine. It uses gravity to keep the insert in place as the mould closes around it.
The overmolding process
During the overmolding process, you start by forming the base layer (around an insert, if need be). Next, you inject the extra plastic layer (or layers) over and around the component. Depending on the compatibility of the material, you can use one or more synthetic resins to create a specific texture or a certain look.