MULTIPRODUCT MULTIVEHICLE INVENTORY ROUTINGPROBLEM DENGAN MIXED INTEGER LINEAR PROGRAMMING(STUDI KASUS PT. GADING MAS INDAH)

Multiproduct Multivehicle Inventory Routing Problem (MMIRP) is an extension of Inventory Routing Problem (IRP) that integrating route and inventory decisions simultaneously to minimize total transportation and inventory costs. This paper aims to implement The MMIRP method with considering vehicle’s fuel consumption rate at PT. Gading Mas Indah where is one of The LPG agents in Malang City which distributes Bright Gas 5,5 Kg and Elpiji 12 Kg products with two vehicle to dispersed sub-agen and retailer customers. In distributing activities the company does not pay attention a route sequences and inventory at the customers. As a result, the expenses of transportation costs is very high and when the customer is visited the inventory level is still high. These problem are solved using Mixed Integer Linear Programming with LINGO software. The results obtained after applying MMIRP resulted in a total distance can savings of 1,75% or 9,77 Km per week, reducing total fuel consumption of 13,39% or 11,84 liters per week and minimizing total transportation and inventory costs by 16,01% or Rp. 119.590 per week.