PTG stirring the imagination of electric car OEMs

Powerstir friction stir welding, from PTG Heavy Industries

As sales of hybrid and all-electric cars continue to gain momentum, Rochdale-based PTG Heavy Industries is busy applying its considerable knowledge of friction stir welding to help automotive OEMs address some of the challenges associated with the manufacture of electric-powered vehicles.

Peter Jowett, PTG Heavy Industries’ Applications Manager, said: “Longer battery life and reduced vehicle weight through the greater use of plastics and aluminium panels, are well known objectives for electric car makers,” comments

“However, the development of electric cars has brought other less-well-known challenges for vehicle manufacturers,” he continues.

“For example, how do they fabricate lightweight, robust and aesthetically sealed battery housings efficiently – particularly when the heat generated by traditional welding techniques could so easily damage the highly sensitive electrical components that the housings contain?

"With our considerable expertise in friction stir welding, we are providing automotive OEMs with highly viable manufacturing solutions for battery housings, solutions which involve no surface finishing and remove the risk of heat damage to delicate components.”

As manufacturers of the world-acclaimed Powerstir range of friction stir welders, PTG Heavy Industries is an acknowledged leader in this innovative means of jointing metals. Working with magnesium alloys of 3mm – 5mm in thickness, and to tolerances of typically 50 microns, the company is currently assisting automotive OEMs in the production of vehicle battery trays, associated electronics boxes and coolant units, by using its 2D friction stir welding techniques.

Using industry standard CNC systems, fitted with PTG Powerstir friction stir welding software, data-logging and multi-axis interpolation, 2D welding can be carried out on accurate tool paths, together with force control to create consistent welded seams.

Mr Jowett added: “Our work to-date, involving the production of automotive battery enclosures using friction stir welding techniques, is exciting and is providing novel opportunities for vehicle design engineers to achieve both light weight and structural rigidity in electronics units that benefit from superior high-strength welded joints."

Since their launch, Powerstir machines have attracted considerable interest from organisations seeking an innovative way of creating superior high-strength welded joints. Used primarily for jointing aluminium, magnesium, copper, titanium, steel, lead and zinc, the Powerstir friction stir welding process provides a clean, highly aesthetic alternative to traditional welding. It delivers proven weld quality, excellent mechanical properties, virtually no porosity and the opportunity for reduced wall thickness in many applications.

Patented by TWI (The Welding Institute), friction stir welding is a unique and innovative means of jointing metals. The process combines frictional heat with precisely controlled forging pressure to produce extremely high-strength joints that are virtually defect free. Friction stir welding transforms the parent metal from a solid to a plasticised state. This occurs during a process that involves mechanically stirring the materials together to form a high-integrity, full-penetration welded joint.

Powerstir applications include:

• Heat sinks and electronics enclosures
• Locomotive train and carriage panels (aluminium)
• Aircraft fuselage and avionics development
• Truck bodies, caravans and space frames
• Boat and ship panel sections
• Flat and cylindrical fuel tanks and bulk liquid containers
• Aluminium bridge sections, architectural structures and frames
• Pipelines and heat exchangers
• Electrical motor housings

Incorporating the brands of Binns & Berry, Crawford Swift, Holroyd and Holroyd Precision Rotors, Precision Technologies Group (PTG) has established itself at the forefront of high precision machine tool design, build and supply. The PTG range includes heavy duty lathes, deep hole drilling machines, friction stir welding machines, ultra-precision grinding machines for rotor, thread and gear operations; rotor milling machines and special purpose machine tools for the manufacture of precision components. Industrial sectors served range from aerospace, medical and mould tool and die to marine, power generation, mining, oil and gas, steel, high end and heavy automotive. PTG Heavy Industries works closely with The Welding Institute (TWI).