Spray method speeds production

Metal spraying techniques enable Midlands product consultancy John Yair Designs to make injection mould tooling for prototypes in half the time it takes to produce aluminium tools.

By using a low melting point fusible alloy sprayed on to a master model it now takes around two weeks to make a toolset.

The tools withstand runs of up to 500 parts in shot weights of typically 45g on a moulding area up to 4500mm2.

Prototypes are made from the same material as the end product. JYD uses the spray tooling on two injection moulding machines a 22-tonne Boston Matthews and a 6-tonne MCP 25KSA.


Parts in Minutes is a polyurethane prototyping system being used by boat maker Outboard Marine to increase productivity fourfold, producing four prototype engine housings a day. Parts are used for structural tests including heat deflection at 130 C, tensile strength of 35MPa and impact strength of more than 35kJ/m2.


The Alerto office chair developed by German maker Mauser uses two engineering polymers and finite element analysis to comply with German and US standards.

For the seat and back a DuPont Zytel grade with 30% glass fibre reinforcement provides strength, impact resistance, stiffness, processability and good surface finish. Mechanical properties are good enough for the arms to be fixed directly to the shell without metal inserts.

The material can be moulded to a wall thickness of just 2.5mm. A flexible horizontal strip of DuPont Delrin 100 acetal resin across the back of the chair acts as a spring, allowing the user to adjust the angle simply by leaning against it.


DusorB is a high-performance acoustic absorber laminate that can be tailored across a range of applications from interior trim to engine housings.

Various facings and encapsulations resist oil, diesel, anti-freeze and other contaminants. Some permit steam and high-pressure water cleaning.


Motor shafts which drive the chemical mud used by the oil industry to control the drilling process need low stiffness and high strength to bend up to 2 /ft and return to their original position. They must also have good fatigue resistance.

Materials supplier Brush Wellman has solved the problem with copper beryllium Brush Alloy 25. It avoids mud pick-up because of a low coefficient of friction.


Specialist stainless steel supplier Hayes Metals sells a range of billet suitable for forging and reforging applications offshore.

Supplied sand blasted or fully ground, grades include duplex F51 and calcium injected 316 and 304 for improved machinability.