Injection Moulding is a manufacturing process for producing plastic parts in small, medium or large volume. It is most typically used in mass-production processes where the same part is being created hundreds, thousands or even millions of times in succession.
Why You Might Want to Use Injection Moulding
One of the main advantages of plastic injection moulding is the ability to scale production all together. Once the initial costs have been paid (The Mould tool) the price per unit during injection moulded manufacturing is extremely low. The price also tends to drop drastically the higher the quantity ordered/ produced. Other advantages include the following:
Injection Moulding Leverages Repetition & Consistency
Plastic Injection moulding is very repeatable. That is, the second part you produce is going to be practically identical to the first one etc. This is a great characteristic when trying to produce brand consistency and part reliability in high volume production.
Low Scrap Rates with Injection Moulding
Injection moulding produces low scrap rates compared to other manufacturing processes like CNC machining which cut away substantial percentages of an original plastic block or sheet. This however can be a negative relative to additive manufacturing processes like 3D printing that have even lower scrap rates.
Waste plastic from injection moulding manufacturing typically comes consistently from four areas:
- The sprue
- The runners
- The gate locations
- Any overflow material that leaks out of the part cavity itself (which doesn’t happen very often)
As and when possible, we will grind up the sprues/runners and any reject parts. We will then add that material back into the raw material that goes into the injection moulding press.
This material is referred to as re-grind.
Our quality controller will limit the amount of regrind that is allowed to be placed back into the press. (Some performance properties of the plastic can degrade as it is moulded if we were to use to much or add re-grinded material over and over throughout the injection moulding product run).
So Is Injection Moulding the Right Option for My Project?
Before you endeavour to produce a part via injection moulding consider a few of the following things:
Start with Financial Considerations
You’ll want to determine the number of parts produced at which injection moulding becomes the most cost-effective method of manufacturing.
From there, you’ll want to determine the number of parts produced at which you expect to break even on your investment (consider the costs of design, testing, production, assembly, marketing, and distribution as well as the expected price point for sales). Build in a conservative margin.
And don’t forget about entry costs. Preparing a product for injection moulded manufacturing requires an initial investment on tooling.
Here at Dudley associates we can offer a few different options to help keep the costs low at the beginning such as prototype tooling instead of a full-scale production tool. We also run a few different reports on the design of the part such as a mould flow analysis to ensure we are confident the part can be injection moulded before the tool is manufactured in house to ensure we spot any potential issues before any work has taken place.
Next, Let’s Talk Design Considerations
When it comes to part design, you want to design the part from day one with injection moulding in mind. Simplifying geometry and minimizing the number of parts early on will pay dividends down the road.
But be aware this again is something we can help you with if needed.
When designing the mould tool, the top priority is to prevent defects during production. Therefore, we run multiple reports before designing the tool and after. We also keep you updated throughout this process. We will also run through this with you during a DFM (Design for Manufacturing) meeting and if we believe there are any minor issues or changes needed, they will be highlighted and discussed for you to decide on with our support of course!
Injection Moulding: The Bottom Line
Injection moulding is a great technology for finished production on a small, medium, or massive scale. It is also useful for finalised prototypes that are used for consumer and/or product testing.
If you would like to find out more or have any questions, please do not hesitate to contact us via email firstname.lastname@example.org or give us a call on 01455 558825.
Alternatively you can contact our sales & marketing Associate on Jacob.Taylor@dudleyassociates.com or 07754 857071.