Study On Accuracy Analysis And Design Of Turntable For Dicing Machine

With the rapid development of semiconductor,the requirement of equipment for packaging the semiconductor is more and more demanding.As an important part of dicing machine,improving the accuracy of turntable is the key to research of dicing machine.By analyzing the accuracy of traditional turntable,this paper finds out the problems existing in traditional turntable with mechanical bearing,and puts forward a solution to replace traditional turntable with hydrostatic turntable,so as to make up for the shortage of traditional turntable.The contents of this paper are as follows:(1)This paper introduces the mechanical structure and working principle of dicing machine.The method of measuring the accuracy about linear axis for dicing machine is introduced.Based on the principle of measurement,the composition of error and its causes are analyzed in the dicing machine.The influence of each error on width of scribing trace is calculated and the distribution of precision for dicing machine is put forward according to the results.(2)This paper introduces the structure of traditional turntable for dicing machine.The measurement of precision for turntable and the principle on which it is based are introduced.From the measurement results of turntable accuracy,it is known that the traditional turntable accuracy of dicing machine is poor.The simplified model which causes the errors of traditional turntable is analyzed.The influence of the positioning precision and turning precision of turntable on the three indexes of cutting trace width,the shape of cutting trace cross section and edge breakage are analyzed.(3)This paper introduces the working principle of hydrostatic turntable,and designs a kind of hydrostatic turntable is suitable for dicing machine.The computing method of concentric theory is selected according to working environment of turntable in dicing machine.The parameters of driving motor are calculated according to hydrostatic turntable.The system which provides oil for hydrostatic turntable is calculated and designed.The methods are put forward to improve the accuracy of machining and assembly.(4)Solidworks is used to build three models,which are fluid model,statics model and modal model.In order to analyze the hydrostatic bearing,the fluid simulation of hydrostatic bearing was carried out with the fluent ansys module as a tool.The diagram describing distribution of pressure in the results of simulation is in accordance with the distribution for pressure of hydrostatic turntable designed in theory.Static structural is used to analyze the hydrostatic bearing,and the diagram describing the distribution of stress and strain for hydrostatic bearing is obtained.According to the results of static analysis,the deformation of hydrostatic bearing caused by pressure of the oil is analyzed.In order to get the natural frequency and mode of vibration for hydrostatic bearing,the modal analysis of hydrostatic bearing is carried out by using modal module of the ansys.Solidworks is used to analyze the motion of turntable,and the characteristics of motion parameters are obtained.