Case Studies

ITS Vision Solution for Automotive Component Inspection

Industrial Technology Systems Ltd (ITS) has completed a vision inspection system for an automotive plastic injection moulding plant, enabling it to check for the presence of manually fitted clips and bolts on fender and bonnet spats after moulding.

ITS’ solution includes an inspection station with six Cognex In-Sight 5000 series cameras, chosen for their durability and flexibility, a supervisory PC and several sets of interchangeable tooling to accept the different models of moulded spats.

Four Cognex In-Sight 5100 cameras, with PatMax®, are used to check that the four clips are fitted to the left and right fender spats. Because the assemblies are manufactured in black plastic with grey and black clip fixtures, the inspection process requires exceptional precision because of the colour identification issues.

Two high resolution, 1600 x 1200 pixel Cognex In-Sight 5403 cameras, with PatMax®, are fitted to measure the position of a manually fitted bolt, and the presence of a washer fitted over the bolt. PatMax® is an extremely powerful algorithm used to accurately find and measure patterns in difficult situations.

Each camera features its own on-axis Cognex IFS LED ring light system, which when used in conjunction with a lighting configuration devised by ITS, combats the difficulties with poor contrasting parts. Two low angle, high frequency fluorescent ring lights are used to illuminate the clip edges, making the use of edge detection tools possible for the inspection. Before any parts are fitted by the operator, the cameras check for short shots in the moulding, allowing the part to be rejected without adding more value to it.

A supervisory PC is used to control the sequence of operations of the cameras, and to interact with the operators, and two Zebra barcode printers. Communications between the cameras and the supervisory PC is carried out using OPC via Cognex’s OPC server.

The inspection stations independently check left hand and right hand operations, and follow the sequence:

• Manually load the part to the correctly fitted tooling
• Manually trigger inspection
• The supervisory PC locks the part into the tooling and triggers the correct set of three cameras to check for short shots in the moulding and flag a reject if there is a problem. If the part is acceptable the supervisory PC generates a unique serial number and prints a label via one of the two barcode printers
• Once step three is passed, the barcode label is manually attached to the bolt receptacles, the correct clips are fitted for the model and the fixing bolt, and the cameras re-trigger
• The supervisory PC then triggers all cameras to inspect for the correct presence of clips and the bolt, measures the bolt position and reads the barcode label. Any failures can be re-worked and re-inspected, or the inspection aborted. This completes the sequence for the fender spats
• Once step five has passed in the bonnet spat sequence, the operator fits a sponge washer around the bolt and manually re-triggers for the presence of the sponge washer
• When the inspection is complete or aborted, the part is released from the tooling. Images are stored at all points of the inspection sequence.

The customer was so pleased with ITS’ work and the performance of the solution that they approached ITS to extend the system to cover different models.