Machine vision promotes profits
Andy Wilson Editor at Large
At a recent press conference held by Messe Stuttgart International in Germany, the organizers of the Vision `98 International Trade Fair used as a venue the engine-manufacturing facility of Daimler-Benz AG (Stuttgart, Germany). During the conference, Claus Lorcher of the department of digital image processing/optoelectronics, Daimler-Benz`s Unterturkheim plant, explained the commitment his company has made to automating its diverse parts-manufacturing and inspection processes.
Approximately 120 image-processing systems, ranging from intelligent cameras to three-dimensional geometry systems are now deployed at Daimler-Benz vehicle plants throughout Germany. One such system inspects the fuel-injection system of the company`s latest A Class engines (see p. 7).
According to Lorcher, deployment of such systems started in 1986 when an articulated system from ASEA was converted into a gantry robot to automatically manipulate crankcases. "This was followed in 1987," says Lorcher, "by four systems that performed optical character recognition of black-painted stamped axle parts for quality-control purposes."
In the last ten years, Lorcher has seen a dramatic change in the way machine-vision systems are deployed. "The early systems we installed involved individual systems that had to be retrofitted in existing production facilities," he says. "As such, they were expensive and often not cost-effective. Now, machine-vision systems are well accepted and are usually installed in new production plants. Consequently, they are more cost-effective," Lorcher adds.
To cost-justify the $80,000 spent to deploy the machine-vision system for the inspection of the fuel-injection system of the A Class engine, Lorcher and his colleagues reasoned that as an alternative to human inspection, the machine-vision system is ten times more efficient at detecting engine emissions. Because of this efficiency, quality control of the company`s engines is increased markedly. And, because the system is automatic, manpower costs are reduced. Lastly, from a financial perspective, the purchase of such capital equipment can, under most countries` tax laws, spread the cost over several years.
Significant investment
Despite these positive benefits, the cost of such machine-vision systems still remains high enough to deter their purchase by many manufacturers. Although machine-vision systems are being actively deployed in semiconductor, automotive, and industrial facilities, the costs to implement such systems can sometimes match the purchase price. Indeed, as an in-house systems integrator, Lorcher says that of the total $80,000 system cost, approximately half was accrued by systems engineering to install, set up, and operate the system. And, even today, as hardware prices fall, the disparate nature of machine-vision-system design still requires a substantial engineering investment.
Certainly, as industrial engineering managers realize the benefits of machine-vision systems, they will increasingly buy and use these systems. In sum, though, the only cost justification to corporate management may be that the final product becomes more reliable and less expensive. Asked how the $80,000 cost of his fuel-injection machine-vision-inspection system was justified to Daimler-Benz management, Lorcher replied, "The payback is in sold cars."
