A Solution to the Accuracy of Multi-Pin Positioning Based on Optimization

To ensure the precise relative position between two adjacent parts, multiple pins (10, or even more) are usually set on the parts for positioning. In this case, whether the two adjacent parts can be assembled, and the consequent positioning error is unknown, which might cause a failure in the reasonable selection of parts in the assembly stage, and the reasonable design of relevant parameters (such as the diameters of pins and pinholes, and positional tolerances) in the design stage. In this study, considering the positional tolerance of the pinhole as well as the diameter tolerance of the pin and pinhole, the mathematical model of the accuracy of multi-pin positioning was established, and determined by optimization, obtaining the positioning error. The related assembly experiments were conducted. The measurement results were all in the range of mathematical calculation with the measured data, indicating that the proposed method is effective, and it can provide a direct basis for the part selection in the assembly stage, and the tolerance design in the design stage.