In order to enhance customer's loyalty in a supply chain, many efforts could be done such as upgrading the service facilities and decreasing delivery time. Although these efforts need to extra-added cost, but we can reduce the shortage cost in supply chain. In this paper we consider a five-tier supply chain and assume that the lead time of manufacturers and warehouses can be shortened at an extra crashing cost, which depends on the length of lead time. Also we consider different options with different prices for product transportation between facilities. We formulate mixed integer non-linear model for a five-tiers supply chain with controllable lead time and multiple transportation options and develop a novel meta-heuristic method that combines the Taguchi's feature with Artificial Immune System (AIS) to solve the proposed model. The performance of the proposed solution method has been examined against a set of numeric instances and the obtained results are compared with those provided by AIS and the hybrid of Taguchi-genetic algorithm (GATA). Results indicate that the proposed method can provide better results than the previous solutions effectively. 
Flexible supply chain optimization with controllable lead time and shipping option