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Automation Replacement: Robots

As manufacturers are looking for ways to reduce floor space and increase flexibility, robots are being used to replace conventional automation.

Often, robots are thought of as devices that can do things that people can do, too. Like spot welding or machine loading. Not that people would necessarily want to wield spot welding guns or heft workpieces all day long. But Joe Gazzarato, director of Engineering for the Body Shop Product Execution Group at Fanuc Robotics (www.fanucrobotics.com; Auburn Hills, MI), who observes, "People talk about reducing the cost of manufacturing a product and using lower cost labor-there's nothing lower cost than automation," suggests that there are other ways of using robots that actually compete with...automation.

One of the areas that Gazzarato deals with is spot welding. One of the developments he's seeing is the utilization of robots not only to handle spot welding guns, but to handle workpieces, as well-sometimes both at the same time. He explains that in some instances, a robot will carry a part, put it in a fixture, then rotate its end effector, thereby putting the spot welding gun in position to weld the part. So not only does the single robot perform material handling, but spot welding, too. Clearly, this means that the robot in question has to be rather robust. He says that the company's R-2000iB series of robots, which is available with a variety of reaches and mounting configurations (floor, shelf, and even upside down), offers a wrist payload capacity of up to 210 kg and a front reach of 2.65 m, so this sort of dual-capability can be readily accommodated. There are a couple more approaches to material handling and welding that are occurring, as well. One, he says, is called "pedestal" welding, where the robot is used as a material handling device to put the part in a fixture, at which point spot welding tooling is activated and performs the welding; the robot removes the completed part. The other makes use of two robots, with one robot manipulating the part and the other performing the welding on that part; the two robots are coordinated through the controller. In any case, Gazzarato points out that given the payload capacities, these robots can handle parts ranging from "a bracket for a door to the whole body side ofa small car."

Which brings into focus the whole notion of using robots in place of custom conveyors and other part transfer automation. He describes "part to part transfer with robots rather than traditional conveyance"-such as lifts, conveyors, and fixed transfers-as "a significant trend." The possibilities go from the small and light, obviously, to things far larger and more massive: Gazzarato points out that Fanuc has the M-900 series of robots which are available with a payload capacity of up to 700 kg. That makes one capable of picking up an entire body and placing it on an overhead conveyor, for example.

Gazzarato says that as manufacturers (OEMs and suppliers, alike) are focusing on reducing floor space requirements, the use of robots for handling and processing tasks, especially robots of various sizes and comparatively compact configurations (e.g., running the utilities through the robot rather than attaching them outside), is increasing.

Another robotic development is the use of programmable devices as a flexible fixturing system. Fanuc has developed the F-100iA line of devices that can be used in body shops to handle parts. These are four- or five-axis devices, one of which is a slide so that the body and arm can move along a horizontal plane. With a series of these devices, which can be equipped with various types of end-effectors to handle parts of different sizes and geometries, it is possible to handle part variations with simply a programmed change. For example, if a different model is to be produced, then it may simply be a matter of repositioning the F-100iAs in the cell via programming. This Gazzarato contrasts with swapping out custom fixtures.