LEPS Revs Up Vision Inspection for New Engine Assembly Line

Building a machine vision inspection system for the automotive industry requires a lot of time, the ability to manage multiple project iterations, and industry-leading engineering expertise to design and execute the system. LEONI Engineering Products & Services (LEPS) accomplished all three, significantly reducing scrap cost and improving throughput when developing two separate automated quality inspection stations for a customer who implemented a new approach to quality inspections when building an engine assembly line.

Specifically, the assembly line aimed to be easily integrable while increasing efficiencies in production, assembly, and inspection. The line builder contacted LEPS because it needed to inspect cylinder heads and engine blocks on an automaker’s new engine model for defects and assembly errors after the parts exit the machining process.

After receiving the system specifications from the customer, LEPS developed two vision inspection stations: one for the cylinder head, and one for the engine block. Both stations inspect similar parameters, including defect detection of porosity and scratches on both cast and machined surfaces on six faces of each of the components. The vision system in each station was required to find pores, scratches, and other visual defects 1–3 mm or larger on the block, and 0.8–3 mm or larger on the cylinder head, depending on the location on the part. The vision system for both lines also verifies the presence of tapped holes for further assembling purposes.

In addition to porosity and scratch inspection, the cylinder head workcell verifies the cubing number, detects debris of 5 mm or larger on four spark plug holes near the intake face of the head, and verifies the presence of welch plugs and ball plugs. The vision system in the engine block station verifies the following items: data matrix code and number, presence of 16 different grade or test marks, presence of welch plugs, and orientation (left vs. right) of bearing caps. The targeted cycle time for each station is 52 seconds.

LEPS designed the mechanical system components and programming of the vision system, as well as the calibration of equipment at the customer location. The initial design called for manual repositioning of the engine blocks and cylinder heads multiple times to prepare them for camera inspection, but LEPS persuaded the customer to mount the cameras to a FANUC robot to do the work instead by demonstrating it would cost 30% less for the vision component over the manual approach.

With the robot integration, each of the workcells uses two Cognex smart cameras for the quality inspections and an additional code reader on the engine block station for OCR/data matrix reading for verifying traceability. LEPS also supplied lenses, optical filters, high-intensity LED lighting, and the necessary cabling and mounting brackets.

Upon completion of the dual vision system, LEPS will provide eight hours of application-specific on-site training that covers normal operation (power up and power down) and system maintenance.