رویکرد مبتنی بر مدیریت ریسک برای برنامه ریزی موجودی انبار محصولات "مهندسی برای سفارش"

Engineering-to-order has steadily increased shares of total production. By its own nature, the order specific products often come without pre-defined bills-of-materials which undermines the starting point of prevailing inventory planning methods. Manufacturers often have to confront with difficult, if not impossible, choices for meeting the highly responsive service level without investing in costly inventory, particularly for long lead time items. In this paper, a novel inventory planning approach is presented. Based on predetermined inventory budget, customer responsiveness can be optimized by considering risks associated with supply chain uncertainty, component commonality, substitution possibility, market intelligence, and other salient factors.

Engineering-to-order (ETO) has emerged with growing domination in production systems, particularly for delivering customized products. In order to cope with deep order penetration points (OPP), ETO companies have to find better ways to integrate engineering, manufacturing and supplier capacities [1]. However, often a few unique long-lead time parts become bottlenecks to meet the customers’ expected delivery dates. Unless, customers accept renegotiation, ETO companies have to prepare material in advance to buffer such risks. However, the bill-of-material (BOM) can only be finalized in the later stages of the order fulfilment life cycle, both enterprise resource planning (ERP) and just-in-time (JIT) systems lack the key input to start the planning process [1]. Hence, inventory planning has to make a number of important but unrealistic assumptions and part unavailability becomes unavoidable. Consequently, the delivery can be haphazard, if not unpredictable, for ETO supply chains [1]. Furthermore, high volatility of demand and supply in today's turbulent manufacturing industry further complicate the difficulties of inventory planning. Companies often resort to using additional inventory to achieve target customer satisfaction level. The cost of doing so may quickly drain the company's financial resources. Thus, a viable inventory planning approach requires conscientious inventory budget control to decide the right quantity and right type of stocking points in order to provide the best customer satisfaction while avoiding excessive inventory. To this end, this paper reports the results of a research project that extends the conventional supply chain approach by taking into account the insights of product design, such as commonality, substitution possibility and others, in conjunction with delivery risks in supply and demand in economic terms. For instances, ETO companies may make conscientious business decision to commit some long lead time common modules before order arrival to reduce supplier lead time uncertainty. The target is that ETO companies can align the marketing planning with the financial planning to meet the corporate strategic goals. That is, the objective of this paper is to establish a framework for a given inventory budget to decide inventory placement to maximize customer responsiveness in ETO production scenarios where bill of materials can’t be committed in normal production planning stage.

n this paper, an inventory planning approach for engineering-to-order production based on risk-management approach with consideration of budget constraints is presented. A mathematical framework is developed to allocate inventory in order to minimize the possibility of missing the ETO shipment due date. This approach is applied to the ETO production area of a mechanical engineering company. Simulation results show substantial reduction of inventory in comparison with business as usual. With the mathematical model developed here, there are several possible extensions. One is to link the inventory substitution decision of sales and engineering function, and to employ revenue management approaches to control the substitution. Another possible extension is to consider the effects of material commitment on the life time revenue of customers to decide the release of materials for substitution.