Marine & Transportation

Midas Breathes Life in to New Product

The Key to Successful Manufacturing: Team Work and Supplier Partnership helps get Avon Protection in to Deep Waters

Midas, an established manufacturing company with 30 years’ experience of manufacturing tooling and the highest quality precision PU mouldings knew only too well what was required to complete the Avon MCM100 re-breather moulding set when first approached in 2017. The MCM100 is a deep diving (100m CE rated), air and mixed gas, electronic control rebreather. It was initially developed in collaboration with the UK Defence Science and Technology Laboratory (Dstl), and designed to be compatible with Explosives Ordnance Disposal (EOD) and Mine Countermeasures (MCM) diving operations. The system was developed to deliver a new long endurance, depth capable rebreather so we were really keen to be involved with a product that genuinely helped to protect lives.

The MCM 100 Multi role re-breather had a number of critical aspects that made manufacturing a challenge – large O-ring seals, large external fine threads, a breathing loop system that meant no paint on three out of the five components, an over-moulded rubber part on the outer RIM moulded casing to name just a few! In addition, it was classified as a low magnetic signature device so attention had to be paid to metallic content both in the part and during the manufacturing phases.  This meant that even standard brass inserts typically used within the process had to be re-assessed and sourced from alternate suppliers. 

With prototypes fully tested and customer orders to fulfil, the pressure was on to take this lab based unit to a fully working design that could be built consistently in a production environment. Four months after commissioning development tooling it became clear consistency was not being achieved – an essential factor on such a demanding piece of kit so new tooling and a new partnership was required. Having served the Medtec and Medical markets for the last 30 years, Midas understand regulatory control requirements, materials traceability and the value of standard operating procedures to ensure consistent part production – an critical aspect when moving from a ‘lab’ based process  to a repeatable production line. This depth of knowledge and skill base combined with complete in-house control for both tooling manufacture and moulding ultimately gave Avon Protection the re-assurance they needed to switch supplier and commit completely.

With a critical time path in play it was essential that Midas and Avon worked together in an open and transparent way to dissect the project requirements, take on board lessons learnt to date and run through all DfM aspects and review actions to ensure the end product would have the best chance of success – not just once but on a repeatable basis.

Technical Challenges:

  • Low magnetic signature device made sourcing components challenging. Where female threads were required, brass inserts had to be sourced from a specific company and batch which had been tested.  Process control was essential to ensure the correct inserts were included in each moulding and that any potential risks that would increase the magnetic signature of parts were avoided.


  • No paint element in RIM moulding Reaction Injection moulding (RIM) is a cold casting process whereby liquid plastic is pumped at low pressure in to a mould tool, with aspects closely aligned to the metal foundry industry.  Typically all Midas RIM mouldings are finished with high quality two-pack paint systems once the parts’ feed system have been dressed, any small pin holes have been corrected and split lines and flash lines removed. PU RIM mouldings are almost NEVER supplied in a natural black finish and without defects so to achieve this on three very complex mouldings, on a consistent basis is testimony to three major factors.
    •  The upfront DfM process Avon and Midas spent intense but quality time on before committing to tooling manufacture
    • Top quality tool design with thoughtful feeding and vent systems
    • Exceptional moulding and finishing skill


  • Tolerance control and accuracy Assemblies require the tightest levels of tolerance control and no more was this highlighted than with O-rings sealing faces and external machined threads. A combination of features produced in tool and post machined allowed Midas to create precision mouldings that fitted together to create the desired result.


  • CNC machining is extremely unusual on PU RIM mouldings; the aim is always to capture features within the tool and work with the design to ensure acceptable tolerances have been considered.  However, this project required a blend of both standard and critically tight tolerances (deviations < +/- 0.25mm) for functionality and demanded Midas produce heavy sectioned cast PU parts consistently, with perfect integrity to allow the post machining of fine threads and bearing fit holes


  • Rubber Over-moulding When fully operational the unit weighs in at a hefty 27KGs so to help protect the base of the outer casing, the design incorporated a shore A 85 rubber moulding. This two stage moulding requires consistency of shape and accuracy as each part is set in a secondary tool for the over-moulding phase.


In Summary

By working in partnership, both Midas and Avon successfully delivered a high quality product and fulfilled a critical first order supply that will lead on to setting the standard for other agencies globally. 100% commitment to the project was essential by both companies, willingness to travel at short notice, acceptance for design change and commitment to Rapid Tooling and compressed lead-times. It was only through this partnership approach that promises were delivered – quality expectations were ultimately exceeded and the result is an industry leading product.


If you have a challenging project that requires high quality RIM enclosures, perhaps we can be your next supply partner? Get in touch

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