Optimal Capacity Determination

For a given capacity of a plant the average unit cost of production of a product decreases as the output rate( say in number of units produced per year.) in increases figure . this happens because we known that the fixed cost incurred in the plant, machinery equipment. Remains constant through changes in the volume of output. When a large number of units of the product are produced. These fixed costs get divided uniformly in the large number of units. Therefore the average cost per unit of the product decreases.

When the rate of output is increased beyond a particular limit, the average unit cost start rising because of more frequent equipment breakdowns, fatigue in workers resulting in more defective items, scheduling problems inventory problems, etc. This particular limit of the output rate is called the optimum output rate, for which the average unit cost of the product is the minimum.

Figure: Optimal Capacity Determination

There is a relationship between the optimum output rate , minimum average unit cost of a product and the capacity of the plant. As shown in figure (b) for plants with small design capacity (small sized plant ) the optimum output rate is the lowest and the minimum average unit cost of product is the highest compared to medium sized and large sized plants.

Thus while determining the optimal capacity of a new facility three important factors have to be kept in min. These are the demand forecast available capital and other resources, and the minimum average unit cost desired to keep the competitors at bay.