Evaluation Method of Assembly Yield in Three-Dimension Single-Station Assembly Process Based on Number-Theoretical Net and 3DCS

Abstract

Evaluation method of assembly yield in three-dimension single-station assembly process is presented based on Number-Theoretical Net (NT-net) and 3DCS. Firstly, based on the analysis of fixture deviation affect assembly deviation under arbitrary layout, the three dimensional single-station assembly deviation model under arbitrary layout is developed. Then, the principle of generating good lattice point (GLP) based on NT-net method is introduced. Afterwards, taking fixture locating variations which are sampled using NT-net method for input vectors, the samples are substituted into assembly deviation model of dimension variation propagation in single-station assembly processes to get output vectors. The statistics for qualified sample is accomplished, after comparing output vectors with the variations of measuring points on component. Assembly yield in three-dimension single-station assembly processes is gained when qualified sample divided by total sample. Finally, a real case in sheet metal assembly is given as an example to calculate the assembly yield in three-dimension single-station assembly processes. The result is validated by 3DCS.