Principle and simulation of fixture configuration design for sheet metal assembly with laser welding. Part 2: Optimal configuration design with the genetic algorithm

A fixture plays a key role in ensuring proper metal fit-up in sheet metal assembly with laser welding. In this paper, an optimal fixture configuration design model is proposed based on a new locating scheme which includes both total locating and direct locating on welds. In this model, both the number and the location of the concerned locators are taken as objectives. The proposed prediction and correction method is used for determining the number of direct locators, and a pattern sorting method is developed for determining the number of total locators. Considering the degree of metal fit-up (DMF) to be a fuzzy quantity, a feasible evaluation criterion of DMF is also developed using a fuzzy synthesis evaluation method. A powerful optimisation technique - genetic algorithm - is employed as the optimisation procedure. A case study is presented which demonstrates the effectiveness of the optimal model, and the degree of metal fit-up can be improved compared to the initial locating scheme