NEW SPIRAL WELDING CASE STUDY

Phil Black - PII Editor 07/05/2010

191 2 minutes read

Listen to this article

With the arrival of their new spiral welder earlier this year, Rewinds & J Windsor (RJW) were uniquely positioned to offer an enhanced technical service to their customers in shaft and other rotating machinery repairs.

Within days the company was asked by a large Northern, oil seed food processing company to repair a rotary diverter lock from the one of their conveyor handling system. The assembly in question was made of 316L stainless steel and measured 2.5m long and 500mm diameter.

The customer established that a new unit would have cost over £20,000 with delivery projected at 18-22 weeks from receipt of manufacturer’s drawings. In fact no drawings were available so redrawing would add further cost and time penalty.

Within hours RJW had collected the rotor lock shaft assembly from site, fully cleaned and inspected it and made detailed measurements. A materials’ analysis was also carried out and confirmed to be 316L stainless steel. Additionally an ultrasonic test was completed to out to ensure the shaft was structurally sound with no inherent flaws or cracks.

The detailed inspection had found that the drive end bearing diameter was bent and worn and the non-drive end also showed signs of wear. In this condition it was effecting its serviceability and could have soon failed catastrophically. As a critical process component this would have led to huge downtime costs and production problems affecting not only the site but their key downstream customers.

The report to customer outlined suggested procedures:-

–    Prepare failed non drive end diameter
–    Machine true and prepare drive end diameter (full length)
–    Set up in spiral welding machine and weld using 316L welding wire and externally approved welding procedures.
–    All stainless steel heat treatments were covered during the process.
–    Set up shaft and proof machine.
–    A dye penetrant inspection was completed and found to be satisfactory following machining.
–    Finish machine and keyway DE and NDE shafts back to manufacturer’s standard.
–    Carry out final dye penetrant inspection.
–    Inspect all work and deliver back to customer.

All work was carried during normal working hours and the unit was returned within 7 working days (if required the job could have been completed in 30 hours using the RJW round the clock service).

It was found that the cost of the job was approximately 15% of new and the delivery of 7 working days was far quicker than the original equipment manufacturer quotation.

This work was achieved during the customers scheduled downtime period and therefore no loss of production was incurred.

By following a best practice path for the repair of the machine, the customer prevented a potential plant failure and benefitted from a re-engineered, fully documented job with an improved specification over the original in a fraction of the delivery time and cost.

For more information contact;

Rewinds & J Windsor & Sons (Engineers) Ltd
81 Regent Road, Liverpool L5 9SY Tel: 0151 207 2074
Web: www.rjweng.com.
RJW: Contact Mark Lavelle 07860-811162