Automotive Front End Assembly System
SUMMARY: Designed, developed and installed a PLC system to control the assembly of front axle assemblies. The units were assembled on a turntable, with operators loading, assembling, and unloading according to a strict sequence of operations, with interlocking verifications.
DESCRIPTION: The system consisted of a PLC, operator pushbuttons and status lights, and an interface to several torque gun controllers. One set of operators prepared the parts necessary for the assembly. This consisted of placing the parts on a cradle at a staging table. Before the bi-directional turntable could rotate, all parts had to be present on the staging table. In addition, in order to assure that the parts were not simply placed on the staging table and assembly parts picked from a bin, each part had to be removed from the staging table before allowing the torque guns to activate. The turntable rotated 180 degrees (alternating CW and CCW), bringing a new frame to the assembly operators. Status lights showed which parts were present and which bolts were properly torqued. Before the torque guns were enabled, predefined parts had to be present on the frame. These were verified by proximity sensors and photocells. Bolts were then torqued. If the torque was within tolerance, the status light showed steady. If the torque were attempted but fell outside of tolerance, the status light blinked. Once all parts were present and all torques were completed properly, the table was allowed to rotate, bringing another empty frame for assembly.