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Tham khảo tài liệu 'surface integrity cutting fluids machining and monitoring strategies_4', kỹ thuật - công nghệ, điện - điện tử phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 464 Chapter 9 b Section through typical high-speed turning chuck. Courtesy of Pratt Burnerd International Ayrton 2003 a Thermal expansion I Shrink-fit tooling the induction coil encircling the tool holder s collar heats the tool holder to the desired temperature - allowing the ambient temperature tool to be inserted then contraction around the shank occurs. Courtesy of Tooling Innovations c Typical characteristics of a high-speed power chuck. Courtesy of Pratt Burnerd International Ayrton 2003 Figure 229. Thermal expansion tooling its operation and high-speed turning chuck details Kinetic Energy Machining and Monitoring Strategies 465 gal loss of the jaws - when rotating at typically high turning speeds i.e see Fig. 229b for a diagrammatic cutaway assembly of an HSM quick-change chuck . These quick-change chucks incorporate a traditional wedge-style and lever mechanism that instead of directly acting on the jaws the radial force acts through the actuator and lever mechanism prior to transferring the effort to the jaws. So when the chuck rotates at high-speed the actuators are thrown outward by centrifugal force but are restrained from moving by the lever which pivots about the central connected sphere. At the opposite end of the lever the jaws are also thrown outward and act to move the pivot in the opposing direction i.e. to that of the actuators - effectively balancing each other. The performance of the counter-balanced chuck depends upon the accuracy of the balance achieved as the actuator mass is constant and the top jaw mass being variable depending upon the particular top jaws in use thus the state of the balance will also vary. As a consequence the clamping force may fall with rotational speed or actually increase with heavy and light jaws respectively. With standard hardtop jaws the clamping force remains almost constant across the range of the operating speed making it unnecessary to calculate the clamping force losses. An additional feature is that the .
