Cost-effective flex for assembly lines.

A cost-effective alternative for the pallets and robots commonly used for lifting components on automotive assembly lines has been developed by Bosch Rexroth Corp. (www.boschrexroth-us.com; Hoffman Estates, IL). According to Rodney M. Rusk, Automotive Industry Manager for Bosch Rexroth Electric Drives and Controls and George Martin, director of Product Development for its Linear Motion and Assembly Technologies organization, the alterative consists of modular automation components--such as ballscrews, linear elements, electric servo motors and drives, and PC controls. They're calling this "Programmable Lift Platform" (PLP).

Essentially, the PLP offers X-, Y- and Z-axis movement. They point out that some assembly lines use pallets that are part-specific--pallets that are not only expensive, but which limit manufacturing flexibility. Other lines are using robots for handling bodies and components, such as for spot welding. These can be comparatively expensive to source and time-consuming to program. So enter the PLP.

The PLP provides part flexibility within the assembly line. According to Rusk and Martin, the deployment of PLPs is largely predicated on weight of the part or body, the size of the part or body, and how the weight is distributed. For example, while a full body might require four PLPs in a cell, a fender might need just one or two for lift and location. Because this is a three-axis unit, programming is far simpler than might be the case for a robot. And unlike some other automation solutions, they claim that six PLP units can be controlled with one Rexroth controller rather than the six PLCs (and appropriate synchronization software) that could otherwise be required.

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