## Publisher

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Emerald Group Publishing Limited

## Laser inspection program saves Lear Corporation $240,000 on a single seat programme Laser inspection program saves Lear Corporation$240,000 on a single seat programmeKeywords: Lasers, Sampling, Inspection

US-based automotive component leader the Lear Corporation have made cost savings of $240,000 on just one seat programme by replacing a template-based seat inspection system with a laser scanning approach using the very latest 3D Scanners ModelMaker software. Lear inspects new automobile seats during design for product approval and during manufacturing for quality control. Previously, this was done by comparing a sample seat to a series of contoured plastic templates indicating the original styling guidelines. Typically about nine templates were needed per seat. These were arranged on the inspection stand in a lattice-type arrangement representing the critical contours of the seat. When a seat was placed next to the latticework of templates, it was required to line up to within 6mm. This was then checked manually by a technician, providing a quick "go-no go" check of seat contour. If the determination was a "no go", the design or production process was revised and another seat was built and inspected. The main drawback was the cost of producing the templates and the inspection stand. Total cost for the templates themselves for a seat program with 29 seat configurations was$104,000.

To reduce these costs, Lear investigated a number of other inspection technologies including laser or white light scanning techniques. Lear ruled out white light systems as they were not stable enough for the factory environment and required highly skilled operators. Lear also ruled out small, inexpensive laser systems as they did not produce enough laser power to scan an object as large as an automobile seat in the plant environment.

The system best suited to Lear's requirements was ModelMaker. The major components of ModelMaker are a 3D laser sensor, an arm or position-sensing device on which the sensor is attached, the PC, and the software that extracts, displays, and manipulates the data. ModelMaker can be configured with several commercially available position-sensing mechanisms. Lear chose the FaroArm as it offered seven degrees of freedom, rather than the six degrees which most position-sensing devices have. This made it possible to reach any point on a seat.

The user now locks the seat into the stand as before, but now that templates are not required, each stand costs $15,000 rather than$22,000 as it does not require the mechanisms that hold templates in place. The user, who needs only minimal training, holds the laser sensor so that a line of laser light appears on the object. The sensor is then moved over the object surface and the data displayed on the PC screen.

For quality control, scanned data was previously compared with the dimensions of a single seat that has received the customer's approval. Because laser scanning goes much faster than template measurements, Lear now scans a number of customer-approved seats and averages the data to set manufacturing tolerances.

Another benefit of laser scanning is that unlike the templates "go-no go" results, scanning provides actual x, y, z coordinates. If an area is out of tolerance, manufacturing can see exactly how much it is off. Although it was possible to measure the distance between the seat and the templates by hand, the accuracy was poor. With the scanned data, the measurement of any discrepancy is highly accurate, helping manufacturing determine the cause of any problems.

Contact: 3D Scanners (UK) Ltd, The TechnoCentre, Coventry University Technology Park, Puma Way, Coventry CV1 2TT, UK. Tel: +44 (0)24 7623 6575; Fax: +44 (0)24 7623 6576; E-mail: contact@3dscanners.co.uk; Web site: www.3dscanners.co.uk