Crane’s Torque Control Solution Ensures Error Free Exhaust Manifold Tightening

The essential requirement of the system was to recognise those engines which require additional tightening before they are fitted to the vehicle. In contrast to a diesel engine the exhaust manifold of a petrol engine is only tightened to 50% of final torque before leaving the engine facility. It was decided not to use normal power tool technology to complete the tightening process. Instead, a simple Poke Yoke error proofing system was used informing the line supervisor of any problems. The preferred supplier of this system was Crane Electronics and the TMAC Opta is central to the solution.

There were also other issues to consider. Firstly the system, and not the operator, had to be able to distinguish between different types of engine. Secondly, the operator needed to receive a visual indicator that the status of the assembly was good (OK). Finally, all recorded torque values had to be documented electronically.

Crane Electronics’ solution was to interface a TMAC Opta with the engine conveyor belt. This involved liaising with an appointed sub-contractor at the plant, who installed the facility and then integrated the TMAC Opta’s input/output capability to the production line control. This proved to be a straightforward process.

Every time a petrol engine is now fed to the conveyor belt, the control system stops the engine on station. The operator knows then that the fasteners on the engine manifold have to be tightened using the IS WrenchMaster tool. The TMAC Opta gives the operator visual indication once the final torque has been achieved.

The sequence of the fastener tightening is always the same and if any are made that are not within tolerance, the system will not release the engine until it is either corrected or the line supervisor tags the engine for rectification.

All torque results are saved and processed by the TMAC Opta. This means that all documentation for product reliability and production analysis purposes is automatically archived.

Crane’s solution is now fully implemented and is ensuring that the safety critical tightening of exhaust manifolds to petrol engines is an extremely accurate process and has minimised the risk of production line stoppages.