This plan includes: independently designing a parallel conveyor line that is compatible with multiple products, independently designing a dual-purpose cylinder hole detection device, independently designing a compatible copying gripper, two Nazhi Fujitsu six axis robots, and independently designing a cost-effective electronic control system. In production, workers only need to place the workpieces in sequence at the feeding position in the front section of the conveyor line. Two parallel conveyor lines can accommodate different products, and corresponding model codes only need to be set on the screen. When the workpiece completes the cylinder hole inspection, the non-conforming parts will be directly thrown into the non-conforming slide by the robot, and the qualified parts will be grabbed by the robot into the machine tool. After the workpiece is processed in the machine tool, the robot will grab the workpiece and place it on the rear conveyor line, and repeat the process in sequence. When there are too many processed workpieces stacked on the conveyor line, the line will detect and issue an alarm, while stopping the robot and waiting for workers to pack the workpieces.