Ten years on, Perkins still prefers Crane torque instruments

Through continuous product and process development, Perkins Engines has grown to become one of the world's leading suppliers of diesel and gas engines in the 4-2000kW (5-2600hp) market. The company's head office is located in Peterborough, which is also home to one of its engine manufacturing facilities. For at least ten years, production line torque measuring and auditing at this plant has almost exclusively been performed using instruments from Crane Electronics, and Perkins has recently invested in the latest models to enable further efficiency improvements to be made.

Five of Crane's latest TorqueStar Opta torque auditing instruments are in use around the plant, with onboard software for performing statistical analyses and SPC (statistical process control) functions. Results are displayed immediately on the TorqueStar Opta's large clear screen, enabling the operators to see immediately if there is an issue that needs to be addressed. Data is also stored on the TorqueStar Opta while the operator completes his checks, and then downloaded onto a PC via Crane's Opta Comms package for further analysis using SPC Lite software.

In addition to the TorqueStar Optas, Perkins also has around twenty of Crane's UTA torque wrenches and CheckStar UTA inline rotary transducers. The advantage of the UTA plug-and-play technology is that the TorqueStar Opta automatically identifies the wrenches and transducers for complete traceability, thereby eliminating the need for the operator to record this data manually and ensuring that errors cannot be made.

Daily and weekly checks

Perkins has set up TorqueStars and transducers on the lines as ready-to-use kits. The Torque Co-ordinators on the lines use the instruments to perform daily checks on key characteristics and weekly checks on all of the inspection characteristics defined for each tool. Although the torque patrols are industry-standard for the joint designs and the processes employed, Crane is able to add value by providing advice and guidance on how to optimise the use of the instruments and Opta Comms package; for example, taking care over how the jobs and rounds are listed on the TorqueStar Opta can help to ensure the torque patrol is completed as efficiently as possible.

Rob Jackson, the SPC Co-ordinator at Perkins Engines' Peterborough factory, is very pleased with the TorqueStar Optas, saying: "Having upgraded to these we have benefited from the increased storage capacity that enables the Torque Co-ordinators to collect the data for the whole line before downloading it at a break time or lunch time. Previously they had to return to download the data before the checks had been completed, which wasted time. In addition, the battery life on the new models is easily sufficient to last the whole shift."

TorqueStar Optas also have the capability to perform statistical analyses, which provides another significant advantage, according to Jackson: "The Torque Co-ordinators can spot an SPC alarm far more quickly now, which gives us much better control and a cleaner process."

In addition to the main production lines at the Peterborough facility, there is also a Project Engine line. This is used to assemble special engines to customers' specifications, either as one-offs or as small batches. The engines are typically modified engines from Perkins' standard range, or new models developed for a specific application. Crane Electronics has been working closely with Perkins in a programme to develop near-100 per cent torque measurement and recording to ensure traceability once the engines have been delivered. Currently Perkins is using a large torque wrench with CheckStar rotary transducers and TorqueStar Optas, but a new ProWrench Opta is being developed with a higher torque capacity to take over this measurement/recording task.

Process capability

Perkins Engines was recently acquired by Caterpillar and is therefore working towards gaining the Caterpillar MQ12005 Bronze quality control standard. This requires rigorous adherence to exacting procedures in order to achieve a Cpk (process capability index) of 1. Without the Crane instruments, this target would be virtually impossible to achieve, such is the critical role played by threaded fasteners in the assembly of engines. Nevertheless, once the Peterborough factory has achieved the Bronze standard, the aim will be to achieve the Silver standard - and then Gold.

Rob Jackson concludes: "We work very closely with Crane and the level of support we get is exceptional. Someone visits at least once every month to carry out training for new people, or just to answer queries or solve any problems. And if we need to see somebody more quickly, that is never a problem. In the past we have had loan and trial instruments, and the instruments we have purchased have always been extremely reliable. Achieving the MQ12005 goals requires continual effort and constant improvement in processes, and I am confident that Crane will be able to support us every step of the way."

Contact Crane Electronics for more information about the TorqueStar Opta, UTA inline rotary transducers and UTA torque wrenches.