Making the Right Choice with RIM

Lets first starting thinking about the pro's and con's of RIM as they help define where it sits in the selection process for your product or new design.  It is rarely a single factor that determines which manufacturing process will ultimately be used so the better your understanding of a process' strengths and weaknesses, the more robust your selection will.  Lets face it, if you have been involved with design or manufacture throughout your career, you will have experienced those stomach churning moments where you realise 'it really was the wrong decision'. 

Thankfully, we all live to tell the tale and with age, we hope comes wisdom!

RIM Moulding Pro Facts

• Scale - You can make a hand held instrument casing or a floor mounted diagnostic machine with 30 individual parts, some as large as 2M in length. This range in scale means you might be able to stick with the same material, supplier and finish for a large machine or a suite of devices, all of which remove obstacles and issues further down the road.
• Order Flexibility - You can have one part, 10 parts or 40 parts per week, every week. The process adjusts to suit market conditions, cash flow, technical stoppages and storage restrictions. Buy what you need, when you need it!
• Budget - Tooling costs are low due to manual operation and stripped back elements.  These costs can be as much as 1/10th the cost of metal injection mould tooling and on many occasions, panels can be merged to reduce part numbers.  All of which reduce risk, assembly time and rationalise the rest of the unit.
• Finishes - RIM mouldings are painted and this opens up opportunities for different colours, multi colour parts through to textured and soft feel finishes. These parts can also be painted alongside other elements such as sheet metal, castings and extrusions to ensure all colours MATCH - very important on multi-panel products.

RIM Moulding Con Facts

• Scale - You can make 2M long parts but try and make an item that is intricate (2mm features) and only 50 mm square, then the process really struggles to compete on both capability and cost.
• Part cost - 'You can't have your cake and eat it' and one of the draw backs with using RIM is that piece part costs can be high. This cost structure works as long as the end product is high value, in low volumes and requires quality finishing.
• Volume - The process limitation is 2000 parts per year/40 parts per week so the closer you get to this ceiling, the more likely you will need to consider alternate processes.
• Finishes - It appears on both the pro's and con's list because painted parts are not suitable for every application - food industry, marine and very aggressive locations to name just few.  That said, the 2-pack paint systems used by Midas are excellent for general wear and tear, chemical and cleaning resistance.