FAQ’s
Frequently asked questions about technical injection moulding and overmoulding in the UK.
Is injection moulding the right process for my product?
Injection moulding is a highly repeatable process and most of the plastic materials you see around you will have been injection moulded although other technologies such as rotational moulding, machining from solid, extrusion and vacuum forming are used in some applications. Injection moulding is best justified if you need a large quantity of parts but once we have built a tool for you we can make 1 item or millions of beautiful, consistent parts in our range of 27 moulding machines. If you need fewer parts or need to prove a concept, then 3d printing may be the place to start – we can help with that too.
What are the costs of tooling?
What type of information is required for quoting a project?
What is the typical process for a new project?
- Discussion around design and application (Firm up DFMA)
- Quote both for tooling and per part (normally within 3-4 days after we agree what you need)
- Make tools and procure appropriate materials (normally 4-12 weeks dependant on complexity)
- Set up Quality Documentation, Method sheets, Jigs and fixtures as required
- Sample, measure and document as required for customer approval
- Commence production to satisfy your orders
What part size limitations do you have?
We deliberately focus our skills on small to medium sized parts. Our maximum projected area is around 400 cm² in PP (polypropylene) whereas glass filled nylon halves that value. The top end is limited by the size of mould tools we can physically fit into our largest presses and the heaviest parts we can make weigh around 450g. At the small end we make many parts that weigh less than 1g.
Can Inoplas injection mould high-performance engineering plastics such as PEEK, PPS and LCP?
Yes. We work with a very broad range of thermoplastics, from everyday materials such as polypropylene, ABS and nylon through to high-performance engineering polymers including PEEK, PPS, PPA and LCP.
These materials are generally chosen where a component has more demanding requirements such as high operating temperatures, dimensional stability, chemical resistance, electrical performance, strength or flame resistance.
The clever bit is not simply getting the material into the machine. High-performance polymers can have quite particular requirements for drying, mould temperature, tool design and processing, so it helps to involve us early in the project. We can review the application, component design and operating environment and help identify a material and moulding process that makes technical and commercial sense.
Can you overmould PCBs, sensors, connectors and other electronic components?
Yes. Electronic overmoulding is one of Inoplas’ specialist areas. We have experience of overmoulding PCBs, cables, connectors, sensors and other sensitive electronic components where protection from moisture, vibration, impact or the environment is required.
The challenge is that electronics generally don’t appreciate being surrounded by hot plastic under pressure. Tool design, polymer selection, processing temperature, injection pressure and the location of delicate components therefore all need careful consideration.
A successful overmoulding can replace several separate components or assembly operations while creating a robust, neat and potentially highly water-resistant finished product.
Where conventional thermoplastic overmoulding isn’t the best answer, we can also discuss alternatives such as low-pressure moulding, encapsulation or potting. Give us the component and the problem and we’ll help work out the sensible way of protecting it.
Can TPU or TPE be overmoulded onto nylon or another rigid plastic?
Potentially, yes. Plastic-to-plastic overmoulding, for example a soft TPU or TPE moulded onto a rigid nylon component, can produce a single component combining strength with grip, sealing, flexibility, vibration damping or impact protection.
The important word, however, is potentially. Not every pair of polymers will bond reliably together.
Material compatibility, surface condition, moulding temperature, component geometry and the amount of mechanical interlock in the design can all affect the strength of the bond. Sometimes chemical adhesion does most of the work; sometimes good component design is equally important.
We therefore prefer to look at the complete application rather than simply answering “will material A stick to material B?”. We can review material datasheets, component geometry and operating conditions and, where appropriate, carry out trials before committing to full production tooling.
What tolerances can Inoplas achieve with precision injection moulding?
There isn’t one sensible tolerance that applies to every plastic moulding. Injection moulding tolerances depend on the polymer, part size, geometry, wall thickness, tool construction and processing conditions.
Plastics shrink as they cool and different polymers behave very differently. Glass-filled engineering materials, for example, behave differently from an unfilled polypropylene, while features close to a gate may behave differently from those at the opposite end of a component.
This is why we prefer to discuss critical dimensions at the design stage rather than discover them after the tool has been made.
For specialist applications Inoplas has produced very fine-featured mouldings, including work with LCP involving wall sections down to around 0.3 mm and extremely tight dimensional control. That doesn’t mean every drawing should suddenly acquire microscopic tolerances – our engineers will happily tell you which dimensions genuinely need to be tight and which ones are simply making the toolmaker’s life unnecessarily exciting.
Can Inoplas help optimise my component for injection moulding before tooling is made?
Absolutely – and this is normally the cheapest point in the project to solve problems.
Our engineers can review a component for Design for Manufacture and Assembly (DFMA), looking at features including wall thickness, draft angles, ribs, bosses, undercuts, material selection, expected shrinkage and critical tolerances.
We also use SOLIDWORKS Plastics mould-flow simulation where appropriate to help predict how molten polymer will behave as it fills the mould. This can highlight potential filling, cooling, warpage or tooling issues before steel is cut.
We can work from an existing component, 2D drawing, 3D CAD model or sometimes simply a description of what the product has to do. Rapid prototypes can also be produced using our in-house 3D printing and machining facilities.
A few hours spent discussing the design at the beginning can have considerable benefit later.
Can Inoplas manufacture insert-moulded parts with metal components, terminals or connectors?
Yes. Insert moulding involves placing another component into the mould tool and injection moulding the thermoplastic around it to create an integrated finished part.
The insert might be a threaded metal component, terminal, pin, connector, cable, electronic component or another moulded part.
Done properly, insert moulding can eliminate subsequent assembly operations, securely locate components, improve sealing and produce a much stronger and neater product. The positioning of the insert and the way it is supported inside the tool are important because molten polymer arrives rather enthusiastically and we’d rather the insert remained exactly where the designer intended it to be.
Our experience includes conventional insert moulding as well as cable, connector and electronic overmoulding, so we can help with both the component design and the production process.
Can Inoplas supply complete moulded assemblies rather than just plastic components?
Yes. Although technical injection moulding and overmoulding are at the heart of Inoplas, many projects continue beyond the moulding machine.
Our capabilities include bespoke cable manufacture, cutting, stripping and crimping, soldering, electronic assembly, ultrasonic welding, mechanical assembly, printing and testing. This means we can often supply a finished or substantially completed assembly rather than sending a customer a box of mouldings and leaving them to organise several additional suppliers.
For OEM customers this can reduce purchasing complexity, transport, work-in-progress and the number of separate quality interfaces within the supply chain.
We are equally happy supplying an individual precision moulding or taking responsibility for a more complete contract-manufactured assembly. It depends what makes most sense for the project.
Where can I find a UK injection moulding and overmoulding company for complex technical components?
Inoplas Technology is a UK injection moulding, insert moulding and overmoulding company based in Wimborne, Dorset. We specialise in technical plastic components and assemblies for OEM and industrial customers in the UK and overseas.
Our work ranges from straightforward thermoplastic components through to high-performance engineering polymers, cable and connector overmoulding, electronic encapsulation, insert moulding and complete assembled products.
Projects can also be supported with CAD and DFMA, mould-flow analysis, rapid prototyping, tooling, material selection and production engineering.
All manufacturing complies with our ISO 9001:2015 quality system, with inspection, traceability and documentation including PPAP, ISIR and SPC available where projects require them.
If you have a drawing, CAD model, existing component or simply a problem that needs solving, send it over. If it’s made from plastic – or you think it possibly ought to be – there’s a reasonable chance we’ll have some useful ideas.