AIA: Subassembly Line Makes Perfect Cylinder Heads
Mack Trucks (Hagerstown, MD) has installed a semiautomated cylinder head subassembly line manufactured by Veri-Tek International (Wixom, MI). The line is based on Veri-Tek's SMART Manufacturing technology-lean assembly systems with integrated in-process verification.
In the beginning, Mack merely sought to automate and verify keeper-lock installation on the existing cylinder head subassembly. However, the project grew into a complete line incorporating manual and automatic processes, such as intake and exhaust valve installation and verification, pin and seal pressing, automatic keeper-lock installation with laser verification, and torque-controlled yoke adjustment.
The VT-1000 signature analysis system is at the heart of the system. The VT-1000 monitors critical assembly operations and ensures that the assembled cylinder heads have the correct valves installed with the correct keeper locks in place.
The new line integrated some existing machinery for cost savings. Cylinder heads start at a rollover station where the valves are inserted. A poka-yoke, or error-proofing process, ensures that the valves are inserted correctly. At the next stations, the pins and seals are inserted with a press, the springs and retainers are manually assembled, and the keeper locks are automatically installed and verified with a laser. At the final station, the yoke is adjusted, and the completed cylinder travels down a gravity conveyor to the main line for assembly to the short block.
With the new line, Mack has reduced direct labor on the line by two people and eliminated the possibility of heads with incorrect valves, and missing or incorrectly installed keeper locks from making it through production-all with reduced cycle time.
For more information on signature analysis, call 248-560-1000 or visit www.veri-tek.com.