Study The Method Of Improving The Manufacturing Process Stability Of Assembly Water Pump

For the water pump manufacturing company,the impeller's assembly dimension is one key dimension.This dimension has to be assembly into the customer drawing specification requirement.Otherwise the parts have to be reworked or scrapped.For the mass production process,how to produce more qualified parts rather than rejects,that is one important task.If the company have high production manufacturing capacity,then their produce waste rate and cost will be low,and they will be more competitive.Currently,most method is mainly use air cylinder or hydraulic cylinder to press the impeller into position set by servo.This method cannot avoid the bearing length tolerance impaction,so the manufacturing process stability of water pump is not high.And the rejects quantity is high.In order to keep the high yield rate of the products,we analysis the factors which will impact the manufacturing capability of assembly water pump by fish bone:the alternating current servo electric cylinder is chosen after analysis,the fixture is designed according to the real product,the press parameter is optimized,additional position sensor is added,then the method is issued by using external sensor transport signal to the electric cylinder to set finial press head stop position.This design goes through application,test,validation and the results show that the system have high manufacturing capability.And then can improve the yield of water pump mass production,decrease the waste and cost from company side.The thesis study content include:introduce and analysis the main characteristic of water pump and its assembly process method and theory,study the main characteristic of the press device,and study the relationship between the water pump assembly method and the press device;and the relationship between press force and assembly dimension;use additional position sensor,compare the difference between transit and not transit the PLC,all these related key factor to improve the manufacturing capability of assembly water pump.From the prototype test result,we can see the device(method)has high manufacturing capability,can satisfy mass production yield rate.With the device(method)to assembly water pump,the capability can reach to grade A.CPK data improved from 0.75 to 1.50.Scrap rate improved from 12000PPM to 3.4PPM,which means The number of defective products per million products can be improved from 12000 to 3.