Fabrication and test of an electric spindle integrated with an electromagnetic balancer
This paper focuses on the development of an electric spindle integrated with an electromagnetic ring balancer. Firstly the electromagnetic ring balancer is designed and then 3D model of self-balancing spindle integrated with this balance er is created. Based on the design, an on-line balancing principle of self-balancing spindle is proposed. The prototype machine fabrication process of the balancer's key parts including coil, counterweight disc and toothed disc are discussed. For an actual spindle, the detailed design and development of this balancer are done, particularly the balancing craft of the combined rotor is done on a balance machine before delivery. By installing the balancer on the front end of spindle using flange, a self-balancing spindle prototype is obtained. In workshop, the vibration test of the developed self-balancing spindle is carried out in the range of 3000r/min to 9000r/min. The result shows the developed self-balancing spindle has a vibration velocity below 0.5mm/s. Finally the two eddy current sensors are applied to evaluate the vibration suppression capability of balancer, the experimental result is that about 15um peak-peak value can be eliminated when the correction value of balancer changes from 0 to 38.55g.cm in 3000r/min.
Development of the active balancing device for high-speed spindle system using influence coefficients
Abstract A high-speed spindle can be very sensitive to rotating mass unbalance which has harmful effect on many types of rotating machinery. Therefore, the balancing procedure is certainly needed to reduce vibration in all high-speed rotating systems. In this study, an active balancing program using influence coefficient method and an active balancing device of an electro-magnetic type with both simple and reliable structures were applied to the developed high-speed spindle system. A gain scheduling control using influence coefficients of the reference model was proved to be effective in balancing the spindle system although its characteristics were changed. The stability of reference influence coefficients was verified by experiments with frequency response functions. The active balancing experiment of the manufactured spindle system using an active balancing program and device was also performed efficiently during the operation. As a result, controlled unbalance responses after balancing work were below the vibration limit at all rotating speed ranges including critical speeds.
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.