Research On WL And Card-based Control Approach For Job Release In Mould Shop Floor

Mold companies are typical of small quantities of resource-oriented manufacturing enterprises, the mold is an ETO product that is assembled by several key components, different key components are manufactured in different workshop. The order has many uncertain factors, such as random arriving, product diversification, different processing path and so on. Because of the characteristics of mold manufacturing, the environment of manufacturing workshop is very complex. If not effective control of the completion time of the key components, it will have a great impact order delivery on time, and so lead to frequent tardiness.Studies have shown that the workload control (WLC) is a specific production control approach designed in the complex production environment. It is divided into three control structures, and it is an effective solution to balance the workshop workload by controlling step by step. Although WLC theory is relatively mature, it is not widely used in manufacturing enterprises, mainly because of the lack of an effective way to express. But card system developed from Kanban theory has good physical operability and observational. In view of the advantages of the two theories, this paper main to design a card-based control approach and a card-based control system for job release in mold shop floor.Based on the above research objective, this paper mainly includes the following:Firstly, to solve the control problem for job release in flow shop, this paper designs three workload-based card operating mechanism (direct workload method, complex workload method and probabilistic workload method);summarizing the task selection rules in mold shop floor; giving the steps to set the card parameter; with the method of simulation modeling, running the three card operating mechanism simulation, by comparing the result, it shows us some guides to choose the appropriate control strategies in different target of the shop floor.Secondly, to solve the control problem for job release in job shop, some corrected card operating mechanisms are proposed (corrected direct workload method and corrected complex workload method); giving the approach and the steps of setting card number based on the weighted average processing time; with the simulation modeling method, the result shows the proposed control approach is reasonable.Thirdly, doing some research on the influence of shop floor characteristics on setting the card number norms, the characteristics include the flow characteristics and routing length of a job. With experimental design and a lot of simulation, obtaining the optimal value of the card number in different shop characteristics, the summary reveals the rules of the influence of shop floor characteristics on setting the card number norms.Finally, a production planning and control system prototype for mold companies is designed, and making a summary of the steps of implementing the card-based system.