Structure and application of HSK tool holder
HSK (German-Italian Hohl SchaftKegel abbreviation) tool holder is a double-sided clamping tool holder developed by the Machine Tool Research Institute of Aachen University of Technology in Germany in the early 1990s. It is the most representative double-sided clamping tool. Shank, since 1987, by the German Technical University Machine Tool Research Laboratory (WZL) and some tool manufacturers, machine tool manufacturers, user enterprises and more than 30 units set up a special working group, in M. Under the leadership of Professor Weck, the research and development of new tool systems began. After Duolun's research, the working group submitted a standard proposal for "Automatic Change/Ningxin Shank" to the German local standard machine tool organization in July 1990. Germany announced the filing of the DIN standard for the HSK tool system in July 1991, and suggested to the International Organization for Standardization to formulate relevant ISO standards. In May 1992, the International Organization for Standardization ISOTfrC29 (Tool Technical Committee) decided not to formulate the ISO standard for automatic change/J hollow handle. After the second round of research by the working group, Germany formulated the official industrial standard DIN69893 for the HSK tool system in 1993. In May 1996, under the deliberation meeting of ISO/TC29/WG33, the HSK factory-only system based on DIN69893 was formulated. ISO standard draft ISO/DISl2164. After several revisions, the official ISO standard IS012164 for the HSK tool system was promulgated in 2001. Because its stiffness and repeatability are several times to dozens of times higher than standard taper shanks, it is widely recognized and adopted in the machinery manufacturing industry. For example, in Germany's Mercedes-Benz and Volkswagen, HSK/J shanks are widely used in milling, drilling and turning.
    The HSK tool holder adopts the double-sided positioning of the tapered surface (radial) and the flange end surface (axial), and the machine tool realizes a rigid connection with the spindle. When the tool shank is installed on the machine tool spindle, the hollow short taper shank can fully contact the taper hole of the spindle and play a centering role.
    At this time, there is still a gap of about 0.1mm between the flange of the HSK tool holder and the end face of the spindle. Under the action of the tensioning mechanism, the backward movement of the tie rod causes the tapered surface of the front end to radially expand the elastic jaws, and the outer tapered surface of the jaws acts on the 30-degree tapered surface of the inner hole of the hollow short taper shank. The short taper shank produces elastic deformation, which makes the end face of the tool abut against the end face of the spindle, and realizes the simultaneous positioning and clamping of the tool shank, the taper surface of the spindle and the end face of the main glaze. The main advantages of this shank construction are:
    (1) Effectively improve the rigidity of the combination of the tool holder and the machine tool spindle. Due to the combination of taper surface and end surface over-positioning, the effective contact area between the tool holder and the spindle is increased, and the double-sided positioning is performed from the radial and axial directions, which greatly improves the combination rigidity of the tool holder and the spindle, and overcomes the traditional standard taper. Weak point of insufficient stiffness of the handle when rotating at high speeds.
    (2) It has high repeated positioning accuracy, and the automatic tool change is fast, which is conducive to the realization of high-speed ATC. Due to the taper used, the length of the taper is shortened (about I/2 of the similar size of the taper shank). After each tool change, the contact area between the tool holder and the spindle is large, which leads to good machine tool performance and improves the repetitive positioning accuracy of the tool holder. Due to the hollow structure, it is light in weight and convenient for automatic tool change.
    (3) It has good high-speed locking. The tool holder and the spindle are locked by elastic expansion claws. The higher the rotation speed, the greater the centrifugal force of the expansion claw and the greater the locking force. According to the German DIN standard, the HSK/J handle adopts a balanced design, and its structure has 6 types of A, B, C, D, E, and F. Each type has a variety of sizes. Type A and B are automatic tool changer, C and D are manual tool changer for machine tool. E and F types are keyless connection tool holders, suitable for ultra-high-speed cutting.