Variation propagation control in mechanical assembly of cylindrical components

Variation propagation control is one of the procedures used to improve product quality in the manufacturing assembly process. The quality of a product assembly depends on the product type and the optimization criteria employed in the assembly. This paper presents two assembly procedures of component stacks by controlling variation propagation. The procedures considered are: (i) straight-build assembly by minimizing the distances from the centres of components to table axis; (ii) parallelism-build assembly by minimizing the angular errors between actual and nominal planes. Simulation results are presented for the assembly of four cylindrical components. The results indicate that the variation can be reduced significantly by using these procedures, compared to that without minimization. The results also indicate that the variation not only greatly relies on the assembly procedures, but also on the number of available orientations at the assembly stage. The radial variation increases with the stage for the straight-build assembly, while the angular error decreases with the stage for the parallelism-build assembly. The assembly quality for the two assembly procedures can be improved by increasing the number of orientations. The variation decreases exponentially and monotonically with the number of orientations. The information obtained is useful for manufacturing processes and the assembly modeling.