How to choose the right tool holder to effectively control costs

Due to the different tool clamping methods, a large number of factors such as dimensional accuracy, surface quality, changeover time and tool wear will be affected. Therefore, the tool holder has a direct impact on the quality of the workpiece and the processing cost. In cutting processing, the tool holder is the key interface between the tool and the machine tool. In various processing occasions, whether the correct tool holder is selected will affect many factors, such as: dimensional accuracy, surface quality, changeover time and tool wear, which ultimately affects the quality and cost of the processed workpiece.

Just as there are different processing occasions, there is no tool holder on the market that can be used for all processing needs. Therefore, with the development of processing technology, SCHUNK has developed five different high-precision tool holder systems for more than 30 years. With these sets of tool holders, users can meet the needs of various cutting tasks. Its applicable industries range from micro-machining in the electronics and watch industries to high-speed metal cutting processing (HPC/HSC); there are both high-value and high-precision tool holders, and inexpensive tool holders suitable for large-volume processing.

The clamping rotation accuracy determines the dimensional accuracy of the workpiece being processed.

High-precision toolholders, such as TENDO hydrostatic expansion toolholders and TRIBOS stress-locking toolholders, have undergone a series of dynamic balancing calibrations in addition to the high structural size guarantee in manufacturing to achieve high clamping rotation accuracy. This feature not only improves the quality of the workpiece, but also greatly reduces the processing cost. The processing cost consumed is significantly lower than the traditional processing cost, because the use of high-precision toolholders prolongs the service life of the tool. Compared with traditional spring toolholders, TENDO hydrostatic expansion clamping technology (Figure 2) and TRIBOS stress-locking clamping technology (Figure 3) can save up to 27% of costs just by reducing tool wear.

SCHUNK's high-precision toolholder system has extremely high clamping rotation accuracy, and users can accurately process the workpiece and achieve extremely high dimensional accuracy when using it. Although heat shrink toolholders and high-precision spring toolholders can also achieve high clamping rotation accuracy when leaving the factory, there are still differences due to different clamping technologies. Experiments show that heat-shrinkable toolholders will gradually lose their clamping accuracy due to the influence of thermal expansion of their materials; while TENDO toolholders that rely on the deformation of the hydrostatic oil chamber or TRIBOS toolholders that clamp under material stress deformation at room temperature can still maintain radial rotation runout of no more than 0.003mm after multiple tool changes.

In terms of vibration damping, the values ​​of SCHUNK's various toolholder systems reflect extremely wide adaptability. Among them, the TENDO hydrostatic expansion toolholder and the TRIBOS-R stress locking toolholder are particularly outstanding. The TENDO hydrostatic expansion toolholder clamps the tool through the inner wall of the symmetrical oil chamber, and transmits the pressure evenly to every part of the oil chamber by tightening the pressure bolt with a hexagonal wrench. The inner wall of the oil chamber is pressurized evenly and symmetrically to expand in the axial direction, thereby clamping the tool. With each clamping and loosening, the pressure bolt is fixed to the same position, ensuring the requirements for repeated clamping accuracy. Since the vibration damping of oil is greater than that of steel, the TENDO toolholder also has extremely high damping characteristics. Similarly, the TRIBOS-R stress-locking toolholder uses a cavity structure filled with plastic damping material, which also has similar damping characteristics, thereby achieving an extremely quiet processing effect. SINO universal toolholders also have similar advantages because they are equipped with a plastic material lining.