How often have you had a project that would be ideally suited to plastic? Injection moulding appears to offer the best solution but there is one major drawback — the section is too great or the part is very large.

In certain circumstances you could use gas-injection for thick section mouldings, which results in a hollowed out centre to a moulding, for example a handle.  Whilst this creates the impression of a solid moulding, the true section is not so great and the finished item is cheaper to produce as a result.  But what if a solid moulding is a key requirement and void-free mouldings would be preferred?

Rutland Plastics has considerable expertise in large and thick section mouldings, in excess of 100mm in some cases and over 1m2.  Choice of materials can be a crucial factor.  Certain materials will not mould without voids or other defects common to thicker sections, such as sinks.  It has been found through experience that polypropylene and polyethylene are both good polymers for producing void-free mouldings.  Tool and component design are also key factors in producing mouldings that meet the requirements of the application.

One of the downsides to thick section moulding is the long cycle time required. Not just for the injection of the material but more importantly the cooling time necessary to produce mouldings that are stable once they are ejected from the mould. Although this may be costly in terms of machine time, the alternative may be even more costly, for instance the cost of machining from solid, either plastic or another material.

So, if you require a strong, large thick sectioned component, possibly void-free, do not dismiss injection moulding as an option. Of course, there are design considerations but Rutland Plastics would be happy to advise on these drawing on its vast experience in this field. Similarly, if you have a large part then injection moulding may offer a cost effective solution, especially if a single large injection moulding can replace an assembly which is expensive and time consuming to produce.

A quick glance at our plant list and you will see that Rutland Plastics has a wide range of moulding machines and, in particular several large moulding machines. Such a range is unusual for a trade moulder but provides us with the flexibility to meet most requirements. The largest moulding we produce weighs 48kgs and we have the capability to mould parts up to 1.5m2. So if you have a requirement for large plastic mouldings contact us.