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Research paper : Spinning process using robot technology (H. Arai)−156−Synthesiology - English edition Vol.5 No.3 (2012) While the linear motor that was employed to reduce the spinning time was a readily available, existing component, it was used in a slightly different way from the intended use. A linear motor stage is often used as a high-speed, high-precision positioning device, but in our research, it was used as a force control actuator with excellent backdrivability (the property of being pushed back flexibly in accordance with the applied force). The characteristic of bricolage where an attribute of a resource is utilized to realize novel functions can be seen here. Also, using the fact that a linear motor has no loss due to the transfer mechanism, for example, a ball screw, the force control was accomplished by open-loop control without use of a force sensor. This idea was obtained from the author’s experience of the open-loop force control of a direct drive robot (a robot where a reduction gear is not used in the joint axis) carried out over 20 years ago.[20]Through the collaboration with Daitoh Spinning, we were able to increase our repertoire of elemental technologies rooted in on-site use. In the development of the prototype of the working machine, the practicality was enhanced by adding various peripheral functions that conventional spinning machines have, such as a tailstock rod to fix the metal material to the spindle, a blank holder, and a back-up roller that prevents wrinkles in the metal blank.5.2 Accumulation of spinning know-how by trial runs – desire to approach the actual site, the actual thing, and the actual situationIn this research, trial runs as below to fabricate actual parts through joint research with companies played an important role. AIST does not have a site of production and we definitely lacked feedback to the elemental technologies based on the accumulation of experience. For example, even if we successfully formed a noncircular shape, it was merely a simple shape under specific conditions and for a specific material. It had to be extended to various metal materials as well as hot forming under heat, multipass spinning, and complex shapes with steps and constrictions. On the other hand, unnecessary effort would be made if we did not narrow down the priorities of which element should be developed. To select the know-how worth developing and to do so efficiently, the shortest route is to collaborate with companies and to fabricate actual parts. The developed spinning technology will at least be useful for similar parts. It is possible to handle diverse spinning processes by increasing the available know-how and then combining it.Upon receiving a request for trial runs from several manufacturing companies including those involved in sheet metal working, automotive parts, measurement equipment, and metal materials, we fabricated the parts as designated by the companies using our experimental spinning machines, and the know-how necessary for processing was developed (Fig. 11). There were about 10 tests actually carried out, and we received over 30 inquiries. Even if an inquiry did not involve testing, we were able to gain an understanding of which shapes were in demand through the process of meeting with the companies. In testing, since the development lead time was important, we were provided with materials and tools from the companies. We also obtained the necessary design data for improving the machine. The accumulation of sample products through these experiences also provided materials for advertising the spinning method. Although an actual shipment of the machine has not yet been realized, several user companies have requested estimates for the machines from Daitoh Spinning.Through the trial runs, we recognized the importance of the knowledge of plastic working such as material properties. We realized it was necessary to provide the forming know-how as well as the machines to the users. As the number of types of tools and jigs at hand increased through repeated tests, it became easier to handle shapes and materials which used to be difficult. The laboriousness of the formable shapes increased to include square tubes, irregular-shaped pipes, and shapes with curved axis. The range of materials also increased and we were able to expand the know-how of forming noncircular parts. As we repeated spinning tests at factories, the opportunities to incorporate and utilize the on-site knowledge for development increased. The author found that the communication with on-site workers became smooth Accumulation of know-howData for machine designImprovement of machinePractical use of machineTest sampleTrialexperimentDevelopmentof spinningmethodProcessplanningMandrel, material, jigs and toolsPartsspecificationAISTMachine manufacturerParts manufacturerFig. 11 Accumulation of spinning know-how by trial runsFig. 10 Hierarchical structure of elemental technologies… … … Metal forming fieldRoboticsfieldParts spinningPipe spinningSheet spinningTrajectory controlPositioncontrolForce controlSynchronized spinningForce-controlled spinning

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