Use of post moulded inserts
A typical post moulding insert
Post Mould Inserting
Post mould inserting is the process by which a metal, or preformed plastic, insert is incorporated into a moulding by means of a secondary process once the component has already been moulded.
To place inserts into a part once it has already been moulded requires the use of secondary operations equipment. This equipment includes heat guns, powered presses or automated drills. To ensure every insert is positioned in exactly the same location, custom jigs are used so that the moulding will be held in the same position for each inserting procedure.
As with in-mould insert moulding the inserts are specially designed so that they will be held securely in place after the inserting process. The inserts cannot be designed with anchoring pieces extending from them but they can be designed so that they have threads, or cuts, in the side of them. This means that when the plastic cools around the insert it will be securely held in place. For operations that do not use heat the insert will be designed with deep threads on the sides so that they will be held tightly when screwed into place.
Post mould inserting can be a time consuming additional process for some components, but the time taken is more than offset when it goes onto final assembly.
Benefits of Post Mould Inserting
- Ease of assembly – by adding inserts to a moulding the ease by which it can be assembled is greatly increased. Inserts such as clips or screw bolts can be incorporated into mouldings which greatly assist assembly operations and subsequent product performance.
- Increased part functionality – besides adding inserts to aid assembly inserts that improve a parts functionality can also be used. For example, terminal fittings for wires, or seals to make parts watertight.
- Increased component value – any second operation carried out on a part will add value to it. By adding inserts to help assembly or increase functionality, product value will be raised. This helps to compensate for the extra time involved in second operations and ensure products remain cost effective.
- Good part consistency – to carry out post mould inserting jigs are used to hold mouldings while they are inserted. This means that the repeatability of the operation is very good and all parts inserted will be of the same quality.
