When one of the world's biggest car, truck and bus manufacturers needed to join the high tolerance parts of a crucial suspension component it initially drew a blank. After several head-scratching days it turned to TWI for help.
'The job was tricky in that the maker had modified the main axle of one of its vehicles and now wanted to introduce a torsion bar in a very confined space' recalls project team leader Chris Peters. 'The part's function was to reducevehicle roll. It was an odd shape, a tube with two arms attached. So it required two joins between two forgings and a tube...all in a high strength steel'.
Immediately the job sounded like one for TWI's brainstorming service. A team was mobilized using three specialists from TWI and four from the troubled client. Hopefully seven similarly-intentioned engineers, from a variety ofdisciplines, could crack the problem. For a brainstorming meeting to be successful the ground rules must be clearly established at the outset. Perhaps the most important of these, if positive lateral thought is to be fostered, is that"no idea is deemed stupid or impossible".
'We immediately flew out to a meeting at their headquarters armed with a few basics facts about the job' says Peters. 'We knew the component geometry, the materials involved and the shortlist of available factory welding processes'.The TWI team comprised specialists in arc, laser and friction welding. The scope of the job was in Peters's words very broad but the constraints narrow. 'Do we make the join there, there or there...and with which welding process?'Using a large white board and sticky-backed note pads to record feasible, but largely undeveloped ideas, the meeting initially eliminated the arc welding processes. 'Having established some basic ideas we then examined the benefits anddrawbacks of each against the technical, economic and availability criteria' says Peters. 'By the end of the day we had deduced that arc welding was probably not suitable because of its potential distortion characteristics. This was adimensionally high tolerance component and fairly highly stressed.'
Laser and friction joining technologies, were shortlisted for further examination. By late afternoon several candidate processes had been eliminated. This in itself saved considerable further exploratory work.
Friction welding was eventually adopted for closer scrutiny in a production environment. It requires no consumables. It is also fast and greener in power consumption terms than the competition options.
Says Peters; 'I think this job really demonstrated that we have the ability to bring knowledge and experience together to bear on a problem very quickly. So we can clearly, not only deliver technically, but also get the best peopletogether in one room for a rapid result...that's brainstorming!
