Parts assembly has followed the same successive steps since the early 1900s, but in early 2010 the traditional production process marches in a new direction.
"Serial processing has been the norm since Henry Ford's invention of the assembly line, and that's been hard to beat for a century," said Ted Brown, Vice President and General Manager of Powertrain Systems for Comau Inc. in Southfield, MI.
Comau executives plan to alter the serial assembly process with the company's new patents-pending SmartCell, a parallel assembly processing method that combines automatic operations in a single station with all kitting jobs feeding into the assembly cell until the processing is complete.
"SmartCell is customizable. The interchangeable tool sets make it possible to go from one application to another application. In a SmartCell, approximately 80% of the machine is reusable, whereas with all the dedicated tooling necessary for serial processing probably only 30% of the equipment is reusable," said Brown.
Comau's R&D budget for SmartCell was $1 million. "This investment alone is more than what was spent on R&D in the past three years for Comau Powertrain North America," said Brown. The heavy emphasis on developing the SmartCell is poised to provide customers with ample paybacks, including investment scalability.
"Machine tool investment is one of the variables that can drive over-production. Customers typically spend a lot of money on equipment and tooling based on a theoretical volume on a product they think is going to be popular years down the road. A company can match the tooling investment to the volume demand by adding a SmartCell when—and only when—production reaches a specific volume," said Brown.
Perkins is purchasing two SmartCell systems for the company's new four- and six-cylinder Tier 4 heavy industrial diesel engine assembly facilities in the U.K., according to Andy Wheatcroft, Technical Resources Manager for Perkins Engines Ltd. The first SmartCell system is expected to produce cylinder heads in January.
"Automating this [assembly] process primarily ensures repeatable, poka-yoke quality while at the same time dramatically reducing the labor content of this operation," said Wheatcroft.
For the past several months, a SmartCell prototype at Comau's Southfield facility has been assembling seals, valves, springs, retainers, and keys into a V6 valvetrain in 54 s. "Compare that to a traditional V6 valvetrain assembly process that typically requires nine different stations, 18 different pallets, and probably 20 meters of conveyor. Two SmartCells running in parallel will equal the output of a traditional serial process with nine separate operations," said Brown.
According to Brown, when comparing a benchmarked cylinder head assembly process to a SmartCell process, the traditional process—based on 325,000 units annually—has 776 pneumatic motions, input/output switches, valves, and servo motors. The SmartCell assembly system has 232 of those same components. "The best way to improve system availability is to get rid of the things that contribute to system downtime. So if you get rid of 70% of the components that could possibly fail, you have a step-change improvement," Brown said.
SmartCell—described by Brown as "sort of a CNC machine for the assembly world"—is appropriate for nonautomotive markets, such as solar panel assembly, as well as vehicle powertrain and other automotive applications.
"We're very interested in doing high-volume, high-torque motor-stator assemblies. We think the SmartCell is a great machine for such an application because very tight tolerances are required, and this strong machine can deal with magnets. When a complex assembly requires precision, strength, and repeatability, the SmartCell is a good machine for the job," said Brown.