When manufacturing plastic parts, the type of mould used affects the part quality, mould cost and production rate. The mould types discussed in this article include single cavity, multi cavity, and family moulds. Each type has their own advantages and disadvantages. The best-suited mould type for your plastic part will depend on the design of the plastic products being made, where you are in the product development process, required production volume, available capital for investment, among other factors.
Single Cavity Moulds
A single cavity injection mould consists of one cavity as the name suggests. Therefore, only one component is produced per injection cycle. These are generally used for small production volume parts or when products are in the development stage and a family mould is not workable.
- Lower mould production cost compared to a multi cavity mould
- Easier to design and manufacture
- More control over design which can improve the part quality
- Low productivity
- High unit part manufacturing cost
A multi-cavity mould is capable of producing numerous pieces of the same part per injection cycle. While these moulds have a higher initial investment cost simply due to the size and machining cost to make them, they do become very cost effective for higher-volume production runs.
- Shorter lead times
- Lower mould costs per unit/output ratio
- Lower part price for the output quantity/machine time
- Production scalability
- Higher Initial tooling investment than an individual mould
- Tooling lead time is longer due to the machining work required
- If one mould cavity has an issue, the whole mould may need to be removed from the machine to fix it
Family moulds make multiple parts of different designs at the same time, commonly used when the production volumes are relatively low. Family moulds are also commonly used in the development stage of a new product where tooling costs are kept to a minimum while still being able to achieve production-quality components. The design of a family mould is important as the flow of material needs to be taken into careful consideration. The parts generally need to need to be around the same size in order to be able to produce them in simultaneously. The pros and cons of this type of mould are:
- Saves individual mould costs
- Ideal for prototype moulds
- Fast moulding cycles
- Filing unbalance, especially when the parts are different shapes and sizes
- Increased risk of mould defects
- Raw material needs to be the same colour and blend for all parts
No matter your product or application, GSS would be happy to discuss it with you. Browse our Product Guide for a general understanding of the range of products or contact us to discuss your specific product.