Study On Electroplating Technology Of Wear-resistant Parts With Deep Groove And Hook

Groove needle is the key forming part of warp knitting machine.In the process of forming coils on high-speed warp knitting machines,the high-speed friction of the needle core in the groove of the groove needle will make the inner wall of the needle groove thinner,and the continuous friction movement of the yarn will make the needle hook rough,which will lead to problem such as yarn breakage and yarn fluff occur in the spinning process,at the same time which will reduce production efficiency and product qualification rate.The improvement of the hardness and wear resistance of the groove and the hook surface of the groove needle is the key to prolong the service life of the groove needle.Chromium electroplating is often used for the surface treatment of wear-resistant parts,it can quickly obtain a uniform silver-white coating with excellent hardness and wear resistance.Because the needle body of the groove needle is thin and has deep and narrow grooves,it is difficult to obtain a uniform and complete coating on the surface of the slot needle in the general chrome electroplating process.Faced with the problem of electroplating chrome on the surface of the groove needle,after years of technical research,Donghua University has made progress in electroplating fixtures and chrome plating processes for groove needle,and has been able to obtain a complete and uniform coating on the surface of small batches of groove needle.Small batches of electroplating cannot meet the huge demand for the groove needle.This topic focuses on realizing high-quality batch electroplating of the groove needle.The main research contents are as follows:The research of sulfuric acid trivalent chrome plating solution was carried out on the basis of deep plating ability and coating effect.In order to improve the ability of the plating solution to obtain a complete coating at the needle groove,three factors,such as the concentration of conductive salt,the concentration of complexing agent and the plating temperature,which have a great influence on the deep plating ability of the plating solution,were investigated.Firstly,the approximate range of the concentration of conductive salt,the concentration of complexing agent and the temperature was determined by Hull cell test,and then the three-factor and three-level orthogonal experiment was designed,combined with the right-angle cathode method and electroplating experiment of groove needle to determine the optimal value of the three factors,namely c(K2SO4)is 0.8mol/L,c(C2H9Na O5)is 0.6mol/L,and the temperature is 35?.The above process parameters were used to conduct electroplating experiments on the groove needle,and the composition and performance of the coating of the groove needle were tested and analyzed.The results show that the groove needle slot has a relatively uniform coating with a hardness of 680HV~710HV,and the coating contains a small amount of carbon element.Electroplating simulation was used to optimize electroplating fixtures.The design of the electroplating fixture for fine parts depended on experience,and it was difficult to achieve the best results.Through the electroplating simulation method,the best positions of the shielding plate and the accompanying strip of the electroplating fixture of the groove needle were refined and explored.The results showed that the uniformity of the coating at the needle hook and the needle groove was the best when the distances between the shielding plate and the accompanying coating strip and the groove needle were 2 mm and 4 mm,respectively.And the accuracy of the electroplating simulation results was verified by electroplating experiments.the problem of poor electrical conductivity of large-scale electroplating fixtures was researched.The elastic conductive strip was designed to replace the rigid conductive strip and applied to the 80-pin electroplating fixture.After several slot pin electroplating experiments,the qualified rate of the slot pin had reached 98.5%.Exploration of automated electroplating processes and electroplating equipment.On the basis of the electroplating process of small batches of groove needles and fully considering the problems existing in automatic electroplating production,an electroplating process suitable for automatic production was designed.The structure of the automatic electroplating equipment was designed based on the automatic electroplating process.