Abstract:
This research purposes to identify supplier selection criteria and the proper strategy for raw material ordering in automotive industry. This research also brings the suppliers learning ability to be analyzed. The data surveyed from the aspects of the experts in purchasing section of car assembly companies in Thailand is conducted by intensive interview based on the outline of questionnaires with three main points to concern; (1) to identify criteria to select the proper suppliers and the weight of each criteria, (2) to investigate the factors which consider to specify ordering and purchasing strategy and the strategy which affects the purchasing efficiency, and (3) to compare the influence of the factors which affect the suppliers learning rate. The result is analyzed by statistical techniques to formulate the mathematical model. Multi Objective Genetic Algorithm is applied to find the solution. The objectives function consist of total cost, defect rate and percentage on time delivery. Learning equation, formulated by referring the learning rate of supplier from survey informations and regression equation, consists of (1) Supplier Readiness (2) Contract Period (long term and short term) and (3) single and multi sourcing strategy. Additionally, the sensitivity analysis is fulfilled. It shows that the important weight of each criteria and suppliers learning rate affect to the decision. Although the supplier which has higher learning rate and adjustable among uncertainties has worse property than others, in the long term, it can improve to have equal or better property than the others and would be selected by the buyer. Finally, we give some the suggestions for future research.