Key Technology Of Grinding Equipment For Personalized Special Ice Skates

With the Winter Olympics held in China,people are more and more enthusiastic about ice and snow sports,of which the competitive Avenue speed skating,short track speed skating has been widely concerned.The performance of speed skating competition is not only reflected in the quality of athletes themselves,but also closely related to the quality and manufacturing accuracy of special skates.The outline of the ice blade edge for athletes consists of multi-ended arcs,and the ice blade resharpening after use needs to rely on the manual grinding method of the coach,which affects the daily training efficiency of speed skaters,and the personalized sharpening equipment for special ice blades abroad is the neck equipment,so it is necessary to develop personalized ice blade sharpening special equipment with our own property rights.This paper focuses on the development of automated CNC ice skate grinding machines,in-line measurement and its grinding process and other related technologies,with the following main research:For the ice skate’s blade surface roughness Ra requirements of 0.4 μm,shape accuracy of 10 μm high precision processing requirements,through the analysis of ice skate structure characteristics,set up an automated CNC grinding system.Ltd.high-performance CNC grinding machine S7H-M as the main body,equipped with Wuhan Huazhong NC’s newly developed HNC-9 intelligent CNC system,to form a high precision CNC grinding machine.Further,according to the structure and processing requirements of the ice skate,the pressed ice skate special fixture was designed to achieve accurate measurement and automation of the ice skate,and the ice skate’s blade contour was measured with a KEYENCE LJ-X8060 line laser measuring instrument.Finally,a Mitutoyo SJ-210 roughness measuring instrument and a ZEISS CMM were used to check the quality of the ice skate grinding process.Firstly,for the characteristics of professional athletes’ ice skate’s blade profile consists of multiple circular arcs,the line laser is used to measure its profile online,analyze the influence of different measurement methods on the ice skate measurement accuracy,compare the influence of different data processing algorithms on the measurement accuracy,and complete the characterization of the special ice skate’s blade profile.The data collected by the line laser were processed by a combination of Butter low-pass filtering,coif N wavelet and median filtering,and the reliability of the filtering algorithm was determined by examining the standard block contour.Further,a 5th order Sum of Sine function pair was used to fit the ice skate arc with a fitting accuracy error of 0.01 mm and a repeat measurement accuracy of 0.004 mm.Finally,by measuring a section of a standard circular ice knife,the error of the ice knife arc measured by the line laser online was 0.007 mm.Secondly,in order to achieve efficient grinding of ice skates,the grinding process is systematically studied in this paper.The ice skate’s blade is made of high-strength alloy steel with hardness of HRC59～HRC62,which is a difficult material to grind.The main influencing factors of the ice knife grinding process are spindle speed,feed rate and grinding depth.Based on the above three influencing factors,this paper established a multi-objective optimization model using Response Surface Methodology(RSM),adopted the Box-Behnken Design(BBD)experimental design scheme,took three levels for each factor,and used surface roughness and single grinding removal rate as the experimental evaluation criteria to complete the optimization of the grinding process.The best predicted results were 1.144 μm surface roughness and 1.704 mm~3/s material removal rate of the ice skate’s blade,and the predicted process parameters were adjusted and verified by grinding test,and the results showed that the surface roughness was 1.219 μm and the material removal rate was 1.71 mm~3/s.Accordingly,the prediction error of surface roughness ΔRa is 6.15%,the prediction error of material removal rate ΔQw is 0.35%,and the surface roughness Ra of the ice knife is 0.208 μm and roundness accuracy is 2.8 μm in the fine grinding processing experiment,and the results of 10 times repeated experiments meet the processing accuracy requirements.Finally,an automatic correction method and a margin calculation method are proposed for automatic ice skate grinding processing.The standard circular ice skate is used as a machining template,and the curve of its blade profile is measured online by a line laser,then the blade profile of the ice skate with grinding is measured,and the ice sakte grinding volume is minimized by correcting the standard ice knife profile curve and using the corrected curve as the grinding wheel trajectory.Further,the number of rough grinding and fine grinding is planned according to the total grinding quantity of ice cutters to be processed.After grinding in high speed and high precision mode,the profile curves of the grinding blade were measured again and compared with the standard profile template.The results show that the error of the two curves is less than 8 μm,the roughness Ra is 0.269 μm,and the roundness is 6.6 μm.