Evaluation Method and Application of Assembly Yield in Two-Dimension Multi-Station Assembly Processes Based on Number-Theoretical Net

Method for calculating assembly yield in two-dimension multi-station assembly processes is developed based on Number-Theoretical Net (NT-net). The discrepancy of NT-net is analyzed, and the principle of generating good lattice point (glp) based on NT-net method is introducted. Afterwards, taking fixture locating variations which are sampled using NT-net method for input vectors, the samples are substituted into state space model of dimension variation propagation in multi-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 two-dimension multi-station assembly processes is gained when qualified sample divided by total sample. Finally, a real case in automotive body floor assembly is given as an example to calculate the assembly yield in two-dimension three-station assembly processes. The result is validated by using Monte carlo simulation. It provides a new way to predict assembly yield in two-dimension multi-station assembly processes.