Frequently asked questions

1. What is a mould?

A mould is a form that is used to manufacture a plastic product. The mould consists of two halves that are pressed against each other during the injection moulding process. One half often forms the outside of the product, while the other half forms the inside.

2. What is injection moulding?

During the injection moulding process, plastic granules are liquefied by heating them up and then the liquid plastic is injected into the mould. The plastic in the mould cools down and solidifies. Once the product has cooled down and solidified, the mould halves are separated and the product can be removed.

3. How is a steel mould different to an aluminium mould?

There are various differences between aluminium and steel moulds. The most important differences are costs, processing time, sustainability and heat -conduction.

The costs applicable for an aluminium mould are lower than those for a steel mould. This is primarily due to the processing time involved. It takes less time to mill a form in aluminium than it would to do this in steel. As a result, fewer machine hours are necessary, which reduces overall costs.

The shorter processing time of aluminium yields more than just lower costs alone. The time taken to manufacture the mould is shorter too. This means that the lead time from design to production is shorter as well. 

A steel mould is more durable than an aluminium mould. An aluminium mould wears faster than a steel mould does. This makes an aluminium mould especially suitable for products whose printouts are not very large. We are usually able to give a shot guarantee ranging from 25,000 to 100,000 pieces (sometimes) for an aluminium mould. This will depend on the product geometry and also on the plastic that is being used. 

Aluminium has better heat conduction than steel. This means that a product that has been made with an aluminium mould will have gone through a more gradual cooling process than a product that was made using a steel matrix. This will often result in a product which is generally produced more uniform. Added to this, better heat conduction means that the cycle time applicable when using an aluminium mould is shorter than it would be if a steel mould were being used. A shorter cycle time will, in turn, result in a lower product price.

4. What are the advantages of an aluminium mould?

There are a number of advantages to an aluminium mould in comparison with a steel mould. Aluminium processes faster than steel does. This makes a faster lead time possible and costs are lower. As a result, aluminium has faster heat conduction which generates a shorter cycle time regarding the injection moulding process. A shorter cycle time eventually results in a lower price. Faster conduction also means that the product cools down more evenly and that makes the product less likely to warp.

5. How does the life span of an aluminium mould compare to the life span of a steel mould?

The life span will depend on the material used during the injection moulding process. The life span applicable when using PP, PE, PS and similar materials is virtually the same. The life span of a steel mould will be longer when using plastics that are difficult to process. A production series of 25,000 parts is definitely achievable when using aluminium moulds.

6. What is the consequence of the rapid heat conductivity of aluminium compared to steel?

The speedy heat conduction of aluminium means that the product will cool down more evenly. As a result, there will be less stress and products are less likely to warp. A second advantage is the shorter cycle time. A saving of up to 30 percent is possible for products made from PP and PE. To summarise, rapid heat conduction yields time savings and lower production costs. 

7. Should the product design be adjusted if we choose an aluminium mould?

No, it will make no difference to production whether the product is manufactured using an aluminium or steel mould. However, mould construction will be different in this situation.

 8. Are aluminium moulds less suitable for very small and very detailed parts with thin inserts?

This is basically correct. When using aluminium moulds, the smaller and thinner inserts are more breakable than they would be if steel moulds were being used. These type of parts can be produced as prototypes, but not for series.

9. Is aluminium only suitable for small moulds?

Aluminium is suitable for both small and large moulds. This is because at large volumes there can be gained more time savings in the milling of the aluminium. Promatrix produces moulds with dimensions up to 2500 x 1000 x 1000 mm.

10. To what extent can aluminium moulds be polished to achieve a high gloss finish?

In comparison with steel moulds, aluminium moulds are easier and faster to polish up to a high gloss finish.

11. Are aluminium moulds suitable for glass-filled materials too?

A high glass filled material will make an aluminium mould wear out faster than a steel mould, especially at the injection point. Having said this, visible and measurable wear and tear will not be evident in the short term. Experience has taught us that aluminium moulds are preferable to traditional steel moulds for the production of up to 20,000 parts consisting of glass-filled material.

12. Is it possible to texture aluminium properly?

Like steel it is possible to texturize aluminium as well. The same texturing techniques are used to texture steel and aluminium moulds.

13. Is aluminium only suitable for use as an open/closed mould?

No, the same applies for aluminium moulds as for steel moulds. It is very easy to manufacture aluminium moulds that feature slider and other deformation mechanisms.

14. Is it easy to repair a damaged aluminium mould?

Just like steel moulds, welding can easily be applied to repair aluminium moulds. Thus in most cases the occurred damage can be repaired in an aluminium mould by welding.