Plastic injection moulding is ideally suited to producing prototypes and even end-use parts. Once they’re constructed in the client’s desired shape, the steel or aluminium moulds and the rapid injection process offer precision, speed, scalability, and so many other advantages to expedite your production.
However, there are some use cases where injection moulding may not be the most suitable manufacturing method. Just as there are two sides to every coin, there are certain disadvantages inherent to the injection moulding process that may make it imperfect for your project.
That should come as no surprise since every project – including yours – is unique and requires a unique approach.
So, let’s discuss the advantages and disadvantages of injection moulding to help you determine if this is the right manufacturing process to help you achieve your objectives.
The moulds used during the rapid injection moulding process are shaped from steel or aluminum. This allows for a precise and detailed mould that exactly matches your vision. Furthermore, this mould is used over and over again, thus resulting in a consistent output.
Plastic injection moulding offers a high degree of flexibility in terms of the material you want your part to be made out of. This is a huge advantage, as it allows for parts to be made to suit a variety of high-profile industries.
Once the mould has been fashioned, the injection moulding production process is fast and efficient. Even the process to create the mould is short with a lead time of two weeks. This is much quicker than die casting moulds, which have lead times of three weeks.
The price per part produced using injection moulding is low and affordable. This means you could potentially gain a much better ROI on an order for 100,000+ parts using this manufacturing method versus, say, die casting, which has a higher cost per part.
Injection moulding is highly scalable. Tens of thousands of units can be produced from one single mould, which greatly reduces the lead time and the cost per part in the long-term.
It’s no wonder, then, that this process is used to produce most consumer products, including LEGOs
While it’s true that plastic injection moulding results in a low cost per part, the initial front-end cost is high. If you’re wanting a relatively small production, then you may need to go with a manufacturing method like vacuum casting, which has a much lower initial cost. That way, you’ll be able to achieve a higher overall ROI.
The first part of the lead time for an injection moulding prototype project can, admittedly, take a long time compared to other methods. This is because the moulds must be built out of steel or aluminium first before production is even able to start. This can result in a lead time of at least two weeks or more.
If time is a concern, consider asking us about vacuum casting, cnc machining or 3D printing. Both of these methods have lead times of less than a week (depending on the size of the project).
There are a number of part design restrictions that should be carefully considered when designing a prototype model for injection moulding, as there are several limitations you must work around.
For example, we must adhere to a certain range of thickness for the walls of the part and increase their draft angles by 1 degree for every 25 mm of height. These measures protect the parts from warping, sinking, and draft marks.
Unlike 3D printing, where almost anyone with a design can pop a few prototypes out from a push of a button, building a mould tool for a prototype requires careful considerations. Not only is expertise required in designing the tool but also to properly setup the machine to reduce the risk of mould or machine damage.
Following these parameters can be a tedious disadvantage to those who are unfamiliar with designing for the injection moulding process. Fortunately, you can contact HLH Rapid at any time with any queries you may have, and we will aid you in making sure the final injection moulded prototype looks exactly as you envisioned.
Following our previous points, injection mould tools always require careful planning before production. This is because design changes can be very costly. Generally, it can cost from a few hundred to a few thousand pounds. If the changes you need can’t be done on the current tool, you may have to build a new mould which can cost between a few thousand to ten thousands of pounds.
At the end of the day, plastic injection moulding is perfect for lots but not all productions. It’s best for manufacturing low volume, high-quality prototypes, bridging, and production parts. But every individual project will be different, so if you’re not sure if injection moulding is right for you, know that HLH Rapid offers several other manufacturing services that should suit your needs.
