Torque tools ease engine quality control

Edited by the Engineeringtalk editorial team Apr 10, 2008

The ProWrench Opta electronic wrench is point of load insensitive, which means results will be reliable even when it is being used at odd angles.

Mahle Powertrain in Wellingborough has relied on Crane Electronics' torque control products for over a decade.

Due to the increased level of testing required by Mahle and its customers, the company has decided to upgrade its equipment with the latest generation of Crane products.

Dave Burton, Production Engineer at the Wellingborough production plant in the UK explains: "We assemble engines and, depending on the project, typically checking one in 50 engines per shift basis to ensure high-quality tightening of nuts, bolts and fasteners".

Delivering the correct level of torque is crucial in the automotive industry: too little and joints may rattle and loosen.

Alternatively, over tightening can mean fixings are taken past their yield point, which is just as dangerous, and can lead to early failure of the bolted joint.

Mahle purchased the ProWrench Opta and the Torquestar Opta.

The ProWrench Opta is a digital torque wrench which is compact, portable and highly adaptable.

It can be used for low-volume tightening or to rectify joints where the torque is found to be incorrect.

A range of attachments can be fitted to suit each tightening application.

The electronic wrench is point of load insensitive, which means results will be reliable even when it is being used at odd angles.

"With the ProWrench Opta we can check all the bolts on a particular engine in one go by programming it with a sequence of appropriate values (jobs)".

"This represents an invaluable time saving feature", adds Burton.

For high-volume tightening Mahle Powertrain is using air and hand wrenches.

As these tools are not networked, their capability has to be checked and documented as part of an auditing strategy.

Mahle Powertrain uses a Mobile Tool Testing Station (MTTS) from Crane for this purpose.

The heart of this system is a new TorqueStar Opta data collector, which incorporates multiple stationary transducers, joint kits, a printer and a tool reaction post.

As the system is on trolley it can be easily be moved around the production area.

The ProWrench Opta and TorqueStar Opta are both part of a tool range that shares the same user interface and software.

This allows Mahle to store all of its data in one database, using Crane's tool management software, which allows the set-up of all production processes (jobs) onto the Crane system.

These "jobs" can be downloaded to either the TorqueStar Opta or ProWrench Opta when data needs to be collected.

Once all the data has been collected it is uploaded to the tool management software, where it can be exported to a number of third-party software products, such as Microsoft Excel, for further analysis.

The Wellingborough plant purchased the new equipment about a year ago and Crane Electronics will soon be called upon to undertake a re-calibration.