Using a ProWrench Opta digital torque wrench from Crane Electronics, a major car manufacturer has successfully introduced a new method of carrying out checks of the torque values of critical fastenings within its bodyshop.

The checks are carried out three times per shift and are performed using just one 75Nm ProWrench Opta digital torque wrench. The car manufacturer’s previous method involved using various sizes of dial wrenches and the readings were recorded on paper, which was filed at the end of every month. This resulted in an ever increasing archive of recorded data and the potential for misfiled or unclear recorded information.

Crane Electronics’ solution using ProWrench Opta and OptaComms software was selected after careful assessment of the car manufacturer’s lineside torque testing requirements and with the close involvement of the company’s quality control and calibration departments. The tools were rigorously tested together including stringent tests of measurement accuracy. The new method of checking was trialled alongside the existing system before implementation.

The quality supervisor programmes the ProWrench Opta with the data to carry out a specific check of torque values for a particular group of fastenings. The operator simply uses the password protected wrench on the production line. The wrench displays how many bolts have to be checked and what the torque targets are. As the minimum and maximum torque values are held within the wrench, it will then inform the operator via tri-colour LEDS if the readings are low, high or exact. In contrast to a paper based system, operators cannot manipulate data and a true picture of the manufacturing quality is given.

All readings taken are stored with time, date, user and VIN (Vehicle Identification Number). At the end of the shift, results are uploaded to Crane’s OptaComms software and then exported to a spreadsheet of recorded data.

Twelve months into the project, the results have been dramatic. There has been a 50%+ saving in operator time to carry out torque checks and there has been a major reduction in production line stops due to torque checks. The ProWrench Opta records all VIN numbers with corresponding torque readings for each model variant, giving excellent traceability. The virtually paperless system, with electronic archiving, is resulting in reduced administration, together with further cost and time savings. The production line now also has increased daily capacity as a result of faster torque management procedures.

Free information on Crane's latest generation of digital torque wrenches (click here)