Research On Assembly Tolerance And Motion Accuracy Of Key Components Of High-speed Warp Knitting Machine

High speed warp knitting machine is a high precision equipment in warp knitting textile industry.At present,many problems are caused by lacks systematic assembly tolerance and motion accuracy analysis in the design and assembly stage,such as unstable quality,low assembly efficiency and speed increase limit.Firstly,the improvement objectives and key technologies were defined about assembly tolerance and motion accuracy of key components of machine,by analyzing the assembly process of a KS type machine in an enterprise.On this basis,an overall research scheme was proposed,including the analysis of assembly tolerance and motion accuracy,the multi-factor dynamics simulation analysis,the improvement of position measurement and assembly,and so on.Secondly,considering the errors caused by motion stroke and force and vibration,a method based on DP-SDT(Deviation Propagation Small Displacement Torsor)of assembly tolerance was introduced.The tolerance and motion accuracy model of assembly tolerance theory were established,and its corresponding evaluation system were established.Taking the third gear connecting rod frame of crankshaft as an example,the tolerance and motion deviation of the component were analyzed and optimized,and the tolerance and assembly process of its key parts were optimized.Then,unified model parameters based on ADAMS and CETOL6 sigma software,a rigid flexible coupling error comprehensive model considering tolerance and vibration were established,the optimized effect was verified,the test cost was reduced,and the tolerance optimization scheme was determined for the development of prototype.In addition,based on the current equipment conditions in the workshop,an economical and feasible pull rod motion position measurement system was developed,and the measurement algorithm and measurement scheme were formulated.Through the automatic measurement of 45 days pull rod height data of the prototype of high-speed warp knitting machine,the improvement of motion accuracy and speed of the third gear connecting rod frame of the prototype crankshaft were verified,which provided support for the determination and implementation of assembly process improvement scheme.Finally,according to the assembly process simulation optimization scheme of the third gear connecting rod frame of the crankshaft,the assembly scheme of the crankshaft bearing bush in the assembly workshop was formulated,which improved the assembly success rate and the motion performance of the whole machine.Furthermore,a digital ring component debugging method was proposed for the ring component debugging process,which greatly reduced the debugging time of high-speed warp knitting machine and improved the assembly and debugging efficiency of enterprises.In conclusion,through the practical application of the research on assembly tolerance and motion accuracy of high-speed warp knitting machine based on simulation and digital measurement in enterprises,the product performance was improved,the assembly quality was stabilized,the production efficiency was improved.An intelligent manufacturing of high-speed warp knitting machine was built on the technical foundation.