Reaction injection moulding (RIM) was developed in 1969, making it a relatively new process in the manufacturing industry. Since then, it has become one of the more preferred moulding processes due to its flexibility, cost-efficiency and sustainability.
Midas Pattern Co. have offered bespoke reaction injection moulding tools in the UK for over 30 years, our unique, composite resin, Midas ‘MRIM’ Tooling producing highly accurate and high-quality mouldings no matter how complex the parts are. Our flexibility is shown through our experience serving vital industries such as medical, analytical, marine and transportation and environmental.
Here is a short guide explaining how Midas MRIM works, including some special considerations when deliberating which moulding process is right for your product.
What is the RIM Process?
In short, the RIM process involves the mixing of two liquid resin components to create a solid, thermoset polymer known as Polyurethane or PU or PuR. The freshly mixed resin is injected into the mould using low-pressure meter mix equipment which is used to separately heat and pump the two liquids into the mixing head before dispensing directly into the MRIM mould tool. Once the liquid is injected into the mould an exothermic reaction takes place causing the liquid resin to rapidly cure and solidify.
It’s important to note that our thermosetting reaction injection moulding is completely different from typical thermoformable plastic injection moulding. It utilises an exothermic chemical reaction to cure the polyurethane resin into a solid plastic rather than using heat to melt followed by the subsequent cooling to re-solidify the thermoplastic material.
What Materials Can Be Used?
Reaction injection moulding is a flexible process that can use a wide range of different materials. However, we specialise in polyurethane mouldings so only use materials polyurethane chemistry, typically a PuR Polyol Resin and an MDI Isocyanate hardener.
How Long Do RIM Mouldings Take to Solidify?
Although not as quick as the high-volume Injection Moulding of thermoformable plastics, Midas MRIM polyurethane moulding is still a relatively quick process.
To be more specific, products produced through our RIM process typically take less than three minutes to solidify within the mould, however this is entirely dependent on the products properties – size, wall thickness, overall design etc.
If you need a more accurate estimate, get in touch and let our experienced team help you find more of what you’re looking for!
How to Design for a RIM Project?
Although our process is very forgiving and easy to design for, it is still important to make sure you have taken advice from our design team to ensure wall thicknesses, draft angles, fillet radii, clearances, paint allowances will all work perfectly and offer you the very best value for money.
We would also recommend getting in touch with us to get assistance in finalising the design of your product, we offer full design for manufacture (DFM) support, free of charge, to ensure there are no setbacks and production is as effortless as possible.
We offer complete support throughout the entire process, including guidance for your initial design, to ensure your product is made as efficiently and effectively as possible. If you’re interested in our services or want to know more about our Midas MRIM methods, contact us today via email at sales@midas-pattern.co.uk or call us on +44 (0)1234 358394 to get started.