Case Study: Raw power meets precision – IGM Robotic Systems AG
IGM together with Sumitomo Drive Technologies developed one of the greatest manipulators in the world, which set new standards in precision and durability.
IGM Robotic Systems AG is the world's only manufacturer of automated welding and cutting equipment with arc lasers and electron beam technology. More than 2,500 of these systems have been successfully installed worldwide. They are used primarily in the truck industry, in excavator production, railway construction, boiler manufacturing and shipbuilding.
To meet their own aspiration for technological leadership, IGM started looking into new solutions for automated manufacturing for heavy duty applications, to open up new opportunities for their customers. This resulted in IGM's ambitious goal to build one of the biggest manipulators in the world. Manipulators of this type are used for production lines, when very large and heavy objects need to be moved for subsequent processing in a defined work area and must be accurately positioned.
A giant is born
The sheer dimensions of the RWM3/10000AAA-Rci and the L-Arm manipulator are impressive. With an overall width of 7.63 m, a height of 5.93 m and a width of 1.6 m it has a mass of 20.000 kg. Its 3.5 m long rotating arm can swivel around 360 degrees. The result is absolute precision even for the most unwieldly objects. A lifting gear can move this arm 2 m upwards on an axis. To enable treatment from all sides, the workpiece and its mounting plate are placed on a rotating plate.
The tremendous capabilities of this manipulator are reflected in its specifications. The working position repeatability relative to the rotation angle is 0.02 degrees, all that while moving loads up to 10,000 kg.
There was one critical focus point for IGM's engineers, who are already a world leaders in the development of large manipulators: The torque transmission for gears when moving and positioning objects weighing several tons. The gear needs to be extremely resistent to the enormous shock forces created by the abrupt movement of heavy workpieces.
Problem solving through innovation
Conventional gears can not withstand such forces. They would wear out quickly. For this reason, IGM engineers opted for a rolling bearing gear, which by its nature develops only minimal shear.
In their search for a solution to their demanding objectives, IGM's engineers relied on their past experience and again chose Sumitomo Drive Technologies as their gearbox specialist.
Sumitomo's transmissions have some outstanding characteristics, on which the manipulator relied to become a reality: First their are experts at rolling bearing transmissions and thus the torque-transferring parts are not exposed to shear stress. In addition these gear units with have cycloid disks (cyclo principle) – which is crucial for overload reserves of up to 500% which can handle the heavy shock forces.
Besides, the gears are lubricated for their whole lifetime, with reduces overall cost due to minimal maintenance requirements.
Sumitomo also offers motors that can be mounted directly onto the gearbox. Their combined production of motors and gearboxes allows them to create very short, space-saving motor / gearbox units. For the swivel arm IGM's engineers opted for Sumitomo's Cyclo Drive 6000 transmission, with a two-stage motor / gearbox unit, its motor power reaches 6.67 kW and a reduction ratio of 731:1.
For a lathe faceplate a low backlash is very important. Therefore, the project team chose the Fine Cyclo Precision Gear Series F3C-A with zero mechanical backlash. Sumitomo created a custom made version specifically for the requirements of IGM. The directly attached 5.57 kW motor transmits its power via the Fine Cyclo gear with a reduction ratio of 476:1 and allows the precise positioning of loads.
Experience Builds Confidence
Besides pure technical aspects, real life collabaration is very important, not only to IGM. Sumitomo Drive Technologies is always close to their customers. Sumitomo Cyclo Centers are located worldwide and comprehensive service is offered in all European countries through a vast network of local distributors. This ensures that any downtime is as low as possible. The engineer in charge for the manipulators of IGM, Mr. Helmuth Slanz, concludes: “For many years we have successfully been working with Sumitomo. Such an experience builds confidence.”
IGM's and Sumitomo's case clearly demonstrates, how a trustful collaboration between two excellent engineering companies can bring to life even the most aspirational goals.