Injection Moulding is actually one of the oldest forms of manufacturing, dating back to 1872, but it has seen rapid advances in recent years in many areas. Its versatility for design and low production costs have caused it to explode in applications around the world, with much production now coming from China and South-East Asia. It can also be used to form both thermoplastics (plastics which soften under heat) and thermosets (plastics which irreversibly cures under heat). Thermosets are otherwise very limited in their application in other manufacturing processes requiring heat forming.
Injection moulding is carried out by liquefying plastic in a heated barrel where it is mixed with pigments and other additives before being forced into a completely closed-off mould cavity where it cools and hardens to the shape of the cavity geometry. The moulds are usually precision-machined steel or aluminum and can be quite expensive to design and build, so usually only mature finalized part designs make it to this form of manufacturing. The huge advantage that this process does provide is low cost high volume manufacturing since it is highly automated and all trimmings and scrap plastic is recycled to reduce material costs. The largest disadvantage to Injection Moulding is the large investment required to build initial moulds along with large costs for redesigns and corrections. Adding parts to families often requires all new moulds as well. Another consideration is that there are some design limitations related to the requirement that the cavity be completely closed and the part easily ejected without damage, and this often includes limitations on angles, edges and radii.
Plas-Tech currently outsources its Injection Moulding operations to local high quality suppliers that can compete with overseas suppliers on costs while excelling in quality and delivery. We also see local suppliers as being key to maintaining security and confidentiality around our customers’ intellectual property. We find most customers want to be able to visit us in Ottawa and visit Tier 2 suppliers at the same time (all are within 10 minutes of Plas-Tech).
We offer several options around this service:
- Designs can be completed by the customer, Plas-Tech or our partnered moulding suppliers.
- Moulds can be owned and stored by the customer, Plas-Tech or our partnered moulding suppliers.
- At the customer’s option we can source the moulding and the part production separately or together, and we can source with reliable suppliers overseas. Overseas options can reduce part costs by 5-10% compared to local but lead-times and delivery may require some extra planning.
Injection moulding can be used with virtually any plastic and with many designs and applications being within scope. There are some limitations on convex designs, radii, chamfers, edge conditions and overall part size but generally most small to medium size components are well suited for injection moulding once the volumes can support the investment.