Newton Aycliffe-based Permoid Industries has boosted welded fuel tank quality by making changes in its manufacturing procedures. The changes resulted from taking on board expert technical advice available at no charge via the Joining Forces North East business support programme run by welding and joining specialist TWI.
Permoid produces several thousand diesel fuel tanks for earth moving vehicles each year to a demanding service specification. Quality Manager, Steve Toas initially asked TWI to address two issues as part of their continuous quality improvement drive relating to the welding of fuel tanks.
Steve explains: 'Permoid continually seeks to improve its welding operations. It was important to know whether these issues originated from a manufacturing defect or the result of service incidents. We wanted to minimise any need for re-work by improving our procedures so that we can enhance quality and reduce costs.'
Focusing on the tank corner tie-in welds and the drain plug weld region, a TWI engineer carried out a Joining Forces Product and Process Review. This confirmed that despite the combination of robotic and semi-automatic welds in the same application, the corner weld quality was consistent and demonstrated good fusion and met the design requirements of the tank. TWI then gave recommendations on how to maintain this quality on each unit.
Investigation of the second issue, a failed drain plug, revealed that a crack propagated by fatigue from the toe of a fillet weld had caused a leak.
Further examination concluded that this was more likely the result of inappropriate design than of poor weld quality. TWI recommended that further information be gathered about any other failures of this nature before deciding any remedial action.
TWI's help was available to Permoid under the Joining Forces North East technology transfer programme.
For information about TWI's capabilities please contact us.