Comprehensive Error Analysis Of Fixture System And Optimization Of Clamping Sequence

Fixture design is an indispensable link in the manufacturing industry.The design quality of fixtures is closely related to the processing quality of workpieces.At present,in response to the expansion of the production mode of multi-varieties and small-quantities in the manufacturing industry,the application of flexible fixtures is becoming more and more extensive.Therefore,how to improve the design quality of fixtures and reduce the machining errors caused by fixtures has become the primary issue of the thesis research.This paper takes the flexible fixture system as the research object,analyzes the error sources from the two aspects of the fixture system positioning error and clamping error,established fixture positioning error model and fixture clamping error model,and optimize clamping error caused by clamping sequence The details are as follows:(1)Taking the flexible fixture with zero-point positioning system as the research object,aiming at the six-point positioning method,this paper analyzes the reasons of fixture system positioning error,and establishes the fixture system positioning error model including the zero-point positioning error.Based on the actual production situation,random sampling of error sources is carried out,and the distribution law of the workpiece pose deviation including the distribution form,deviation range and expected value of each error component is studied and established,which provides theoretical support for the design and manufacture of fixtures with similar structures.(2)This paper analyzes the mechanism of the error sources causing the clamping error of the fixture system,and establishes a mathematical model between the error sources and the clamping error.Based on the rough surface analysis model,the influence of surface roughness on the deformation of the contact area between the workpiece and the clamping elements is studied,and compared with the results of the contact between the smooth surface,it is found that when the rough surface is considered,greater contact deformation will occur.The value is between 20% and 30%.Therefore,when considering and designing precision parts,the influence of rough surface on contact deformation cannot be ignored.(3)Aiming at the problem of workpiece machining error caused by the clamping sequence of the clamping components,this paper builds a mathematical model for the optimization of the clamping sequence,and proposes an optimization method based on the combination of T-S algorithm and finite element method.Finally,based on a numerical optimization example,a verification experiment on the optimization of the clamping sequence is carried out.Based on the experimental device,the influence of adding other materials between the workpiece and the clamping element on the deformation of the workpiece is discussed.