||Ethylene-vinyl acetate emulsion is the copolymer of vinyl acetate and ethylene, which has been developed as a powerful adhesive base. It effectively bonds substrates such as wood, cotton cloth, hardboard and paperboard. After modifying by adhesives producers, EVA emulsion can bond a great variety of surfaces, particularly effective in bonding polyvinyl chloride films and narrow-pore materials. Adhesives producers provides customized products according to different end users’ needs and consequently have to keep raw materials in stock until orders are placed. The ordering of EVA emulsion is an important issue for adhesives producers because of the seasonal demand pattern and price fluctuation of raw materials. Furthermore, under certain transporting and order restrictions, the ordering quantity is fixed and delivery time has to be made in advance.|
The multi-period inventory models, including EOQ and ROP, are not suitable for analyzing the ordering of EVA emulsion due to the presupposition of unlimited period. This research is based on the case study for NP chemical, using modified ROP model to explore how the selection of service level and delivery time can effect safety stock, probability of shortage, and inventory cost under the conditions of limited period, seasonal demand, given order quantity, and pre-selecting delivery points. The study also constructs a liquid raw material inventory model with fluctuating price and given order quantity in order to determine the optimal combination of delivery points.
The conclusion of this study are presented as follows:
1.Service level doesn’t directly effects the probability of shortage and inventory cost in limited period.
2.The combination of delivery points is the key decision factor because of its causal relationship with the probability of shortage and inventory cost.
3.The optimal combination which leads to the lowest inventory cost can be determined by using the inventory model introduced in this study.