Study On The Surface Finishing Technique Of Transfer Needle

Computerized flat knitting machine is becoming widely accepted and utilized in the knitting industry while the demands for electronic/hand flatbed knitting machines is decreasing. In this case, as an important standardized element of computerized flat knitting machine, the transfer needles are replacing flatbed knitting machines needles to be an ideal alternative for the conventional ones as well. Meanwhile, it also imposes fresh demands on manufacturing quality of the transfer needles with the aim of producing various types of knitted fabrics more efficiently. In this paper, the surface finishing technique of transfer needle is mainly discussed, which obtain the great support from National Technology Support Project-Research on core-technologies of hi-performance machine elements-as an important research subsidiary.The research mainly contains two aspects. Firstly, the mechanical polishing of transfer needle was investigated, and the technical parameters of mechanical polishing were optimized under trial condition. The efficiency and shortage of mechanical polishing have been comprehensively evaluated, which clarified some misunderstanding of the finishing of needle. The results have great reference value for the needle production enterprises to use the mechanical polishing correctly. In order to improve the surface quality of transfer needle thoroughly, it is pursued the partial polishing techniques mainly improving the surface qualities of the needle hook and the shoulder of transfer needle was innovatively proposed.The mechanical polishing of transfer needle was studied using CF 50 Element CF1 X50 ZL. The influence of the parameters including the size of abrasive, the rotation speed and polishing time on the polishing effects was investigated. The optimized processing conditions were determined via trial condition. The efficiency and shortage of mechanical polishing have been comprehensively evaluated under this optimization. The results show that it has apparent effect for deburring and rounding. And the appearance quality of transfer needle was improved evidently. The surface roughness of transfer needle has been a little reduced. However, the main deficiency of mechanical polishing is that the surface qualities still cannot fulfill the technical requirements of transfer needle, because mechanical polishing cannot remove the tiny pleats inside the surface hook and the jagged defects induced by the blanking procedure. This might be caused by the work piece structure and the moving direction of the abrasive.In order to solve the problems mentioned above, the local partial polishing of the needle was initially selected. It is studied the electro-polishing effects on the inner surface of the transfer needle hook and the shoulder of transfer needle. Appropriate tools and electrodes have been proposed and produced. The satisfied electrolyte was founded through experiments. The influence of the polishing parameters on the finishing results was analyzed, including the electrolyte temperatures, the gap of electrode, the voltage and time. As a result, the optimized electro-polishing parameters were obtained. The efficiency and disadvantage of electro-polishing have been evaluated under this optimum condition. The results show that most of the tiny pleats inside the inner hook can be removed by electro-polishing. The surface quality of the surface hook was better than that of KoreaTM which was widely applied in domestic. However, though the most of the jagged defects occurred in the blanking procedure can be removed during the electro-polishing process; the effects of electro-polishing on reducing the roughness of the needle shoulder were not satisfied.The grinding technologies of the needle shoulder were studied too. Appropriate grinding tools and clamp have been proposed and produced. The feasibility of the process route was achieved via trial production. The efficiency of the grinding technologies of shoulder of transfer needle has been evaluated with the optimized condition. The results show that most of the jagged defects can be completely removed by the grinding technologies. The surface quality of the needle shoulder was better than transfer needle of Korea TM as well. Above all, this technique can be practically applied in the mass production of the transfer needles with a world class quality.