PTWA/RSW Cylinder Bore Spray


Plasma Transferred Wire ARC (PTWA) / Rotating Single Wire (RSW)

Engine technology is moving to more compact and lighter engine blocks. This limits the ability to reuse or remanufacture these with traditional techniques such as boring oversized and using a larger piston or fitting a cylinder liner.

The PTWA/RSW process involves machining a small amount of metal off the cylinder bore then replacing it by spraying molten metal in a rotary motion down the bore.

The technology is not limited to remanufacturing of cylinder blocks. It is also being used in new Euro 6 and Euro 7 engines instead of cylinder liners because it has many advantages, such as weight reduction, friction reduction, material cost savings, reduced emissions and oil and fuel economy improvements.

Autocraft’s development of the thermal spray process has taken 12 years to develop. Autocraft has the facility and the licence to use the patented PTWA/RSW process for all our customers in both new and remanufactured engines.

We have designed our facility to be flexible to produce prototypes as well as high volume production, with robotic loading for total flexibility and accuracy. We prepare, spray and hone blocks for foundries, block machinists and OEMs. Autocraft’s unique twin-torch system enables us to coat cast iron liners or blocks with a base coat then apply the top coat. We can also spray directly onto aluminium cylinder blocks with up to 150 Amps.

We have invested £3.85m in PTWA/RSW equipment, development and research to create and optimise our processes. We have capacity to spray over 80,000 cylinder bores per annum. We can also spray and hone cylinder bores or cylinder liners from 65mm to 250mm in diameter.