The micro-variation principle of mating constraints and its application to simulation of cumulative deviations for mechanical assemblies

Simulation of a product's cumulative deviations on its three dimensional model reflects the influence of machining errors on the product's assembly precision effectively. However, there was little research involved on that. This paper presented an algorithm oriented to the three dimensional models of mechanical assemblies to simulate the accumulation of manufacturing deviations. Firstly, the basic theory was studied, and the principle of micro-variation of the assembly constraints was presented, based on which a solution method was given. Secondly, mating constraints defined in current CAD systems were classified, and the equivalent conversions between different type of constraints were set up. After that, the influence of machining error on the mating constraints was analyzed, and a simulation algorithm of variation accumulation was constructed. Finally, an example was given to illustrate the validity and effectiveness of the approach.