Design And Performance Analysis Of A Novel Flexible Conical High Speed Tool Holder

With the continuous improvement of the cutting speed in modern industry,the traditional low speed tool handle can not adapt to the current processing environment,so many different types of ultra-high speed tool handle are born in the world.Among them,the German HSK-E50 shank is widely used with its excellent processing performance.However,due to the limitation of its structure,there are still some problems such as difficult to increase the limit speed and uneven distribution of contact stress on the cone.In this paper,the structure of HSK-E50 shank is improved to solve the above problems,and a new type of flexible conical high speed shank is obtained.The related characteristics of the shank are studied by finite element method.The details are as follows:(1)By combining theory and finite element simulation,the joint performance of HSK-E50 tool shank and spindle was analyzed.The influence of interference,tension force and spindle speed on the joint performance was discussed respectively.It was found that the interference quantity was positively correlated with the contact stress and contact area of the tool shank cone,and the tension force was positively correlated with the contact stress of the tool shank cone and end face.The spindle speed is negatively correlated with the contact stress and contact area of the shank cone.The distribution law of the contact stress on the tool shank cone surface of HSK-E50 was analyzed.It was found that when the tool shank and the spindle tool system were at a static state,the uneven distribution of the contact stress on the tool shank cone surface was the most serious,and most of the stress concentrated on the small and large ends of the tool shank cone surface.(2)A structural improvement scheme of HSK-E50 tool holder taper with blind holes arranged in a regular pattern was proposed,with the common goal of increasing the maximum speed of the tool holder and improving the contact stress distribution of the tool holder taper.The number and size of blind holes on the taper were reasonably arranged,forming a new type of flexible taper high-speed tool holder,which was named20-18-20 tool holder.(3)In order to guide the rational use of type 20-18-20 shank,the interference quantity and limit speed of type 20-18-20 shank were analyzed according to the standard of HSK-E50 shank,and the changes of the connection stiffness of type 20-18-20 shank interface under different interference quantity and spindle speed were calculated.The modal and harmonic response analysis of 20-18-20 tool holder is completed.The results show that,compared with the HSK-E50 shank,the new shank’s ultimate speed is increased by 10.79%.