Servomotor press design - Safety recommendations
Résumé
Servopresses are innovative machines whose sales are increasing. The evolution of servomotors and the recent arrival on the market of power drive systems including safety functions have contributed to their emergence. For example, servomotors are used to participate in the "safe" stopping of the slide when protective devices are actuated. There is still no European or international standard for these specific presses, though a draft is scheduled at ISO standardization level. This document presents an inventory of specific servopress techniques and the results of their detailed study in normal operation and in the case of failure. In particular, it points out that a safety-related power drive system, when affected by a failure, reacts to the latter by initiating a failsafe position which may be different from the initially intended safety function performances. Recommendations regarding the safety functions supported by the power drive system are proposed. For example, safe stop "types" have been defined, describing the different steps assigned to servomotors and those that require an additional mechanical brake to stop the slide in the absence of motor torque. In conclusion, the paper describes the conditions in which the means of protection listed in the standards for the design of "traditional" machines can ensure function.
Domaines
Sciences de l'ingénieur [physics]| Origine | Fichiers produits par l'(les) auteur(s) |
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