Effect of mechanical alignment system on assembly accuracy

Mechanical means of positioning are frequently used in mechanical assembly processes. However very little attention has been paid to the proper design and selection of mechanical alignment systems (MAS) for assembly processes. In this paper, we study the performance of different MAS in terms of assembly accuracy in the presence of the form error, surface waviness and surface roughness of the references surfaces. In particular simulation models are used to investigate how the datum pin configuration, datum pin location and datum geometry of the MAS would affect the assembly accuracy in the presence of surface errors of the workpieces. Our investigation can provide insight into how to design MAS for optimum performance,for assembly accuracy. Our analysis shows that over an order of magnitude of difference in assembly accuracy call exist between using properly designed MAS and poorly design MAS.