Suite of shot peening machines for GM

Automotive company General Motors is sending the strength of its components into overdrive thanks to a new suite of shot peening machines from Wheelabrator Group.

Automotive company General Motors is sending the strength of its components into overdrive thanks to a new suite of shot peening machines from Wheelabrator Group.

Four CFX600 machines from the surface preparation company's Sisson Lehmann product range will be used at General Motors' Powertrain factory in Aspern, Austria.

One of the world's largest automotive suppliers, General Motors' Powertrain division manufactures parts for the company's many different brands, including Chevrolet, Saab, Vauxhall, Opel and Cadillac.

The Wheelabrator machines will treat gears and shafts, including imparting a high internal stress on the gear teeth to increase their strength.

Shot peening is a cold working process, which enhances the fatigue life of parts and is usually associated with the aerospace, medical, auto-sport and other critical product industries.

The enhancement is achieved by propelling a stream of media at components, at high velocity and under fully controlled conditions.

Each impact acts as a tiny peening hammer, causing a thin layer of exposed surface to deform plastically, with high magnitude compressive residual stress, at or near the surface, balanced by a small tensile stress at the deeper core.

Dominique Schwab, technical centre manager at Wheelabrator Group, said: "General Motors needed to increase the internal stress of their components, above existing standards, but their delicate laser marking process made this difficult.

Therefore, it was essential they chose a process which wouldn't damage the precision parts.

"Shot peening is a sensitive process and our machines offer exceptional reliability and consistency, while accommodating different shapes and sizes.

"Our engineers worked closely with General Motors to tailor these automatic machines to their individual requirements, including incorporating an integral loading and unloading system.

Integrated washing machines have been fitted to clean the drive and auxiliary shafts after processing, before they are transferred to the assembly lines.

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