Abstract—Driven by a real-world application in the aluminum industry, this paper provides a mathematical model to tackle the billet scheduling problem at the casting stage. The casting stage is where the molten metal is poured into the moulds to solidify and form the required shape based on the orders’ specifications. The objective is to find an optimal scheduling for the billet production at the casting stage by minimizing the total production time and total set up times on the casting centers. In the aluminum industry, casting is a determinant of plant throughput as the production is limited by the amount that can be cast. So it is essential for the company to minimize setup time and processing time on production lines for a given time period to accommodate potential new orders. The problem is identified as a parallel machine scheduling problem with sequence-dependent setup times with very specific constraints imposed by the process control department to guarantee good quality products. A mathematical formulation to minimize the total processing and set up times on the casting centers is presented. Even though the problem is NP-hard, the model is solved using an exact method on a real case within just few seconds. Experimental results based on randomly generated data sets show that the model is efficient for most instances with reasonable sizes. 