High Efficiency and High Precision Die Machining by Developments of both On-machine Correcting System of Tool Holder Deflection and Tool Holder with High Resistance to Chatter Vibration

为了实现机床高效率、高精度的模具加工，针对主轴与刀架组成的主轴系统不平衡的问题，研究了具有较高抗颤振能力的刀架和主轴转速较高时刀架偏转的在机修正系统。用刀架的刚度和阻尼比的乘积来评价刀架的抗振性能。研究结果如下：(1)研制了一种刀尖带有阻尼器的长刀架，并研究了其对颤振的影响。与不设置阻尼器的刀架相比，设置阻尼器后刀架的静弯曲刚度略有下降，阻尼比提高了9~12倍，具有很好的抗振性能。(2)提出了一种采用扩散焊将铸铁锥柄与合金钢刀架连接而成的刀架。与纯合金钢刀具夹具的实验结果相比，该刀具夹具的抗抖振性能约为合金钢刀具夹具的1.4倍。(3)为了提高刀具夹具在较高主轴转速下的弯曲刚度，提出了一种由密度较小、杨氏模数较高的氧化铝陶瓷主轴和合金钢刀具夹具组成的主轴系统。数值分析表明，主轴转速对刀具弯曲刚度的影响不大。(4)研制了一种通过测量较低主轴转速时刀架挠度的方法，自动修正较高主轴转速下刀架挠度的系统。

To realize both high-efficiency and high-precision die machining using machine tools, the studies have been made of tool holders having higher resistance to chatter vibration and an on-machine correcting system of tool holder deflection at higher spindle speed due to the imbalance of the spindle system composed of the spindle and holder. The chatter vibration resistance of the tool holder was evaluated by the product of the rigidity and damping ratio of the holder. The results are as follows.(1)A long tool holder having a damper within the tip to absorb vibration was developed and examined its effects on chatter vibration. Comparing with the results of the holder without damper, setting the damper resulted in both minute decrease in static bending rigidity of the holder and a 9 to 12 times increase in damping ratio, leading to the huge chatter vibration resistance(2)A tool holder was proposed which was made by connecting the taper shank of cast iron with the holder of alloy steel with diffusion welding. Comparing with the experimental results of the tool holder wholly made of alloy steel, the proposed tool holder had about 1.4 times chatter vibration resistance and equivalent cutting performance.(3)To increase the bending rigidity of the tool holder at higher spindle speed where large centrifugal forces act on the spindle and tool holder, a spindle system was proposed composing of the spindle of alumina ceramic which has smaller density and higher Young's modulus than those of steel and the tool holder of alloy steel. The numerical analyses revealed that the bending rigidity was increased and scarcely affected by the spindle speed.(4)A system was developed which may automatically correct the tool holder deflection at higher spindle speed by the measurements of the tool holder deflection at lower spindle speed.