NDT Line Enhancements
Roundwood Bright Bar in Rotherham produce speciality steels and supply a wide range of hot rolled and cold finished bars for high volume industial markets for applications such as braking systems, drive shafts, mining equipment and torsion bars. It is imperative that the materials are technically free from surface defects and decarburisation associated with hot rolled products.
The original steel bar-rolling line at Roundwood Bright Bar was a stand-alone unit consisting of side loader and bar loading area with multiple test areas and associated equipment.
Over the years, equipment has been added and removed from the Non-Destructive Testing (NDT) line. Non-destructive testing (NDT) is the process of inspecting, testing, or evaluating materials for anomolies or differences without destroying the serviceability of the part. These tests are used to determine the physical properties of materials, in this case steel, such as impact resistance, strength, fracture toughness and fatigue strength.
The original NDT line was under the control of a Siemens S5 PLC. The side loader pocket has since been decommissioned and the bars are now loaded automatically from two paths; the Kieserling line or PBR9. The line can be used as an automatic feed through-path without testing to the new Mair machine that automatically cuts and packs to Pocket 2.
The NDT line has two bar testing units that work independently of each other:
- External checks from the original rotobar tester
- Internal checks via the ultrasonic tester.
Various degrees of decommissioning have taken place on this equipment over the years. Some equipment had been removed, but the cabling, drawings, software, alarms graphics and bar counters all still remained. In addition, upgrades and trials had used sensors from the decommissioned equipment. The software changes from these modifications had evolved in the code as bolt-ons to the original tracking code, whilst the decommissioned equipment had not had its code removed as it formed part of the heart of the system.
When bar faults were initiated from the ultrasonic tester, the algorithm software was unable to determine the actual bar that the fault was associated with. To overcome this, a definite bar gap had been introduced to ensure only one bar could be present in the rotobar tester and ultrasonic tester at any one time. This gap was 11 seconds at best, with the consequence that the NDT line caused a bottleneck on the whole line, slowing down production and productivity.
The aim of the project was to overcome the above issues with the bar rolling line. The solution involved replacing the existing PLC, which was now obsolete, with an Allen-Bradley ControlLogix system and then automate the entire line. The new PLC would then be able to track the location of every bar and enable the operator to view the status of the bars at any time.
The major issue had been using a PLC to provide a method of tracking bar data throughout the cell. With the installation of the new ControlLogix PLC by Fairfields, this meant that the bars could enter the system and be automatically tracked and indexed, speeding up the process and elimiating the bottleneck problem.
The NDT line was successfully upgraded by Fairfields over a relatively short time period of 4 months. The upgrades carried out to the bar rolling equipment gave a noticeably increased throughput, enabling the customer to see an immediate increase in profitability and productivity.