Optimal Research On Assembly Planning For Multiple Head Vertical Rotation Placement Machine

Placement machine is the critical equipment of the surface mount production line, and its speed directly affects the efficiency of the line. The optimal problem of the assembly planning of placement machine belongs to the NP hard problems. It is hard for the traditional methods to get a global optimal solution, and the researches from now on mainly aim at the gantry placement machine and the chip shooter machine. So along with the development of optimization algorithm and the appearance of new type of placement machine, the problem should be researched further.The structural characteristics and working process of the multiple head vertical rotation placement machine are deeply studied in this paper, and then a practical optimization model of this kind of machine is established based on the factors that affect the efficiency; after choosing a kind of intermediate document as the data source of the optimization of placement machine, the optimization can be independent of the different electronic design automation environments; according to the problems of the element characteristics effecting the efficiency of placement machine, new methods of the load balancing of placement heads and the assignment of feeders are proposed, which depend on the layer, variety and quantity of components; combined with working process of the machine, a model of Traveling Salesman Problem for optimizing the route of placement machine is presented; by introducing two kinds of ants which respectively have different functions to the basic ant colony algorithm, the algorithm has been improved.Theoretical analysis and simulations show that the modified algorithm is not only suit for the working facts of surface mount, but also improves the efficiency of the machine further. It avoids the many constraints of old algorithm and the deviation from the working facts caused by simplification of the problems. The optimization idea and the algorithm designed in this paper have reference significances for the new machines which have more placement heads and suction nozzles in the future.However, the optimization of several machines and the parameter selection of the modified algorithm have not been considered yet, so both of them are the research emphases for our future work.