Research On Np_χ-CRL Control Chart Based On Dimensional Accuracy Monitoring Of Hole Shaft Parts

With the implementation of reform,Chinese manufacturing industry has improved signif-icantly.The machinery manufacturing industry is the foundation and pillar industry of a country The development of this industry will directly affect the development of some sectors of the national economy.The machine is composed of various components.The design and the preci-sion of the manufacturing parts directly determine the performance of the machine.The hole shaft parts are the most basic and common parts in the mechanical manufacturing.There-fore,people take the method of mass processing for the commonly used simple shaft parts in the mechanical manufacturing.The dimensional accuracy of the hole-shaft parts is affected by many aspects such as op-erators,gauges,cutting tools,ambient temperatures,etc.In order to ensure the quality of the parts,the three-point inner diameter dial gauge,coordinate measuring machine and other tools can be used to measure the size and check whether it is within the qualified range.However,in the mass production,this measurement method has disadvantages of large workload,high cost and low efficiency.Therefore,the pass-through gauge was invented.The pass-through gauge can quickly detect whether the hole-shaft part is qualified100%inspection and strict rules can control the quality of processing,but in the case of mass production,this quality monitoring method has a huge workload,and its drawbacks are obvious.In 1894,Shewhart proposed a control chart,pointing out that the mathematical statis-tics can be combined to judge the stability of the production stage.It is considered that if the production process is normal,the quality characteristic value of the sample fluctuates randomly If the production process fails,the characteristic value of the sample fluctuates abnormally.The defined rules can judge the state of the production process.This method of sampling inspection reduces the workload of quality inspectors and scientifically improves the quality monitoring effect.In 2009,the first time the regulation was combined with the control chart for quality monitoring which greatly improved the efficiency of dimensional accuracy monitoring.This paper researches how to improve the efficiency of dimensional accuracy monitoring of hole-axis parts by the control chart.On the lathe where the hole-axis parts are produced,a certain amount of samples are taken at regular intervals,and each sample is judged to be qual-ified by the pass-through gauge,and the number of non-conforming products of the sample is drawn to the npx-CRL proposed in this paper,it is determined by certain rules whether the production process has failed.Although the npx-CRL control chart proposed in this paper is a counting type control chart,but combined with the pass-through gauge to measure,the size characteristics can be monitored.The research on the control chart in this aspect has only started in 2009,this article is an in-depth study of the application of the regulation to the control chartWith regard to the determination of the sampling time,the sampling amount and the con-trol line of the control chart,the parameters of the statistical design and the economic design are given in this paper,and the sensitivity analysis of each cost parameter under the economic design is carried out...