Sequential injection moulding is a variant of high-pressure injection moulding where the plastic is injected into the mould through various openings (gates). These injections are sequential rather than simultaneous. The FLUX chair (see case study) is an excellent example of this technique. Sequential injection moulding can also be combined with structural foam moulding.
Large products with thin walls
One of the main advantages of this process is that it allows you to manufacture large products with thin walls. The most extreme example of a product that HSV has created using this technique is the mount for SOLON (see photo), which is produced using 17 gates. First of all, 5 gates are opened and part of the mould is filled. These are then closed and the other 12 gates are opened to fill the rest of the product.
Advantages of sequential injection moulding:
- Possible to manufacture large products
- Weld lines (points where melted plastic flows together) are significantly reduced
Points to consider with sequential injection moulding:
- The injection system is more expensive due to the use of needle valves