Assembly errors analysis of linear axis of CNC machine tool considering component deformation

During the assembly process of CNC machine tool, the assembly dimensions are varied due to the effect of the component deformation caused by gravity. Hence, a mathematical model predicting assembly errors needs to be constructed considering component deformation before tolerance design process. This paper presents an assembly error model of linear axis of CNC machine tool to analyze the effects of component manufacturing error and deformation on axis based on the 3-2-1 localization theory. Thereafter, axis position and angular deviations are calculated under four different conditions, ideal condition, condition considering manufacturing error only, condition considering the effect of structure, and actual condition. At last, the effect of worktable gravity on Y-axis deformation is taken as an example to verify the model. This model can be used to verify the tolerance at tolerance design or to calculate modification amount in assembly process.