Determination of Optimal Product-Mix for a Foundry Using Goal Programming

The time consumed from loading of ingredients into a furnace to the completion of pouring of melt in the molds is known as the heat length and a batch of production is called as heat. In a single heat, different types of castings are produced when the required raw material composition for all these castings are similar. If sufficient numbers of molds for different types of castings that can consume the entire melt quantity are not ready after packing, heat length increases resulting in lesser number of heats per day. However, deployment of too many resources for packing incurs unnecessary cost. In this context, determination of the optimal quantities of different types of castings to be produced in a heat (known as product-mix) and allocation of their molds for packing at different locations is very important. The optimal product-mix will ensure that the leftover quantity of melt in the furnace will be minimum and shortages in the delivered quantities as well as overproduction of different types of castings can be avoided. In this paper, a real time problem of optimal product-mix determination for an Indian foundry is discussed and Its solution Is presented. The expected annual tangible gain from the increased productivity achieved through the deployment of the optimal product-mix of molds for packing Is estimated to be around rupees 11.14 lakhs/annum.