Frequently asked questions
Read the most frequently asked questions about mould making and injection moulding here. Is your question not listed? Please feel free to contact us!
What is an injection mould?
Injection moulds are used to produce plastic products. They consist of two halves, which are pressed together during the process. One half is shaped like the outside of the product and the other half is shaped like the inside.
What is shrinkage?
Plastic is injected into the mould at a high temperature. The plastic then cools inside the mould. When something cools, including plastic, it will shrink. The level of shrinkage depends on factors like the type of plastic. To ensure that the product has the correct dimensions, the shrink value of the plastic must always be taken into account.
What are ejector pins?
Ejector pins are (usually) steel pins that push a cooled product out of the mould.
What is a hot runner system?
A hot runner system is a heated tubing system that ensures that the plastic remains liquid and can thus be injected into the mould at multiple points.
What are the differences between a steel mould and an aluminium mould?
There are various differences between aluminium and steel moulds. The main differences are the costs, the processing time, the durability and the thermal conductivity. An aluminium mould costs less than a steel mould. This is mainly because of the shorter production time. Milling a mould from aluminium takes less time than milling a steel mould. This means fewer machining hours are required, which reduces costs. Besides lower costs, the shorter processing time of aluminium means moulds can be produced quicker. This in turn shortens the lead time from design to production.
Steel moulds are more durable than aluminium moulds. An aluminium mould wears faster than a steel mould. This means aluminium moulds are mainly suitable for products that are manufactured in lower volumes. We can generally give a short guarantee of 25,000 to 100,000 pieces for aluminium moulds. This depends on the product geometry and the type of plastic that is used.
Aluminium has better thermal conductivity than steel. This means that products made in aluminium moulds undergo a more gradual cooling process than those made in steel moulds. This often results in a straighter, more well-formed product. The improved thermal conductivity also means that the cycle time for aluminium moulds is shorter than for steel moulds. A shorter cycle time also reduces the price of the product.
What are the advantages of an aluminium mould?
Aluminium moulds have several advantages compared to steel moulds. Aluminium is quicker to process than steel. This reduces the lead time and cuts costs. Aluminium also conducts heat faster, which reduces the cycle time of the injection-moulding process. A shorter cycle time reduces the price of the product. Faster thermal conductivity also cools the product more evenly, which reduces the likelihood of product deformity.
What is the lifespan of an aluminium mould compared to a steel mould?
The lifespan depends on the material used for the injection moulding. There is almost no difference in the lifespan of PP, PE, PS and similar materials. Steel moulds have longer lifespans when used with plastics that are difficult to process. Aluminium moulds are suitable for manufacturing at least 25,000 pieces.
What is the result of the faster thermal conductivity of aluminium compared to steel?
The faster thermal conductivity of aluminium means products cools more evenly. This reduces internal stresses in the product and thus the tendency to deform. Another advantage is the shorter cycle time: this is up to thirty percent less for products made from PP and PE. In short: the faster thermal conductivity saves time and reduces production costs.
Do product designs made for injection moulding with a traditional mould need to be modified if we opt for an aluminium mould?
No. Production is not affected by whether we use an aluminium or a steel mould. However, the structure of the mould is different.
Are aluminium moulds less suitable for very small, highly detailed parts with thin cores?
This is generally true. With aluminium moulds, small and thin cores are more susceptible to breakage than when using steel moulds. Prototypes of such parts can be produced, but not in mass quantities.
Is aluminium only suitable for small moulds?
Aluminium is suitable for both large and small moulds. After all, large volumes lead to major time savings during the machining process. Promatrix makes moulds of up to 2500 x 1200 x 1000 mm.
To what extent can aluminium moulds be polished to a high gloss?
Compared to steel moulds, aluminium moulds can be polished to a high gloss faster and more easily.
Are aluminium moulds also suitable for glass-filled materials?
A high glass content will result in faster wear in aluminium moulds than steel moulds, particularly at the injection point. Nevertheless, visible or measurable wear will not be encountered quickly. Experience has shown that aluminium moulds are preferable to traditional steel moulds for production runs of up to 20,000 pieces when using a glass-filled material.
Is it possible to texture aluminium?
Just like steel, aluminium is suitable for texturing. Steel and aluminium moulds are textured using the same texturing techniques.
Is aluminium only suitable for open/close moulds?
No, it is similar to steel in this regard. It is perfectly possible to create aluminium moulds with slides and other demoulding mechanisms.
Can damage to aluminium moulds be repaired?
Just as with steel, aluminium is easy to weld. This means damage to aluminium moulds can also be repaired via welding.
What does CAD mean?
CAD stands for Computer Aided Design. The design of the mould is produced using a CAD system. CAD is used to produce a mould design on a computer.
What is CAM?
CAM stands for Computer Aided Manufacturing. CAM is the software used to produce programs for milling machines. Milling machines then run the entire program.
What is a CNC milling machine?
CNC stands for Computer Numerical Control. A CNC milling machine is a computer controlled milling machine. Once a product has been placed on the milling machine, the machine can run the CAM program without human intervention.
What is a robot cell?
Several of our milling machines are equipped with robot cells. These robots automate the CNC milling machine. This automation makes it possible to exchange products and tools on the milling machine. This allows us to mill 24/7 without human intervention.
What is injection moulding?
During the injection moulding process, plastic granules (granulate) are heated until they become liquid and are then injected into the mould. The plastic that enters the mould cools and hardens. Once the product has cooled and hardened, the mould halves separate and the product can be removed.
Which types of plastic can you process?
We work with the most commonly used plastics, including ABS, PC, PMMA, PA, POM, PP, PE and PS. We also use plastics with additives including glass fibres, minerals or talc. We also work with bioplastics and recycled plastics.
What is high-pressure injection moulding?
High-pressure injection moulding is a technique where plastic is injected into the mould at a very high pressure. This technique is suitable for products with wall thicknesses of up to around 5 mm.
What is gas injection?
Gas injection is a technique used to make products with thick walls. Gas is injected during the injection moulding process, so that the interior remains hollow. The gas presses the plastic against the mould to form the outside of the product.
What is 2C injection moulding?
2C injection moulding stands for two-component injection moulding. It is used when a single product must be produced from two or more plastic materials. We begin by injecting the first material into the cavity. The cavity in the mould is then modified and the second material injected. This technique allows us to produce combinations of hard and soft plastics.
What is thermoplastic foam casting (TSC)?
Thermoplastic foam casting (TSC) is also known as low-pressure foam casting. A foam (or chemical blowing agent) is added to the plastic granules. It becomes active when the plastic is melted. This causes the plastic to expand inside the mould. This technique allows thick-walled products to be produced.
What is the cycle time?
The cycle time is the time that the machine requires to produce a single product. This includes the time required to close the mould, inject the plastic, cool it and eject the product.