Scheduling a single machine with concurrent jobs for the frozen food industry

• The studied machine scheduling is for concurrent, multiple job processing.
• The problem considers different processing rates and jobs arrival and departure times.
• The problem addresses the air blast freezing process of the frozen food industry.
• A mixed integer linear programming model and a heuristic algorithm are developed.
• The heuristic algorithm demonstrates the high potential of computational time saving.

This study examines the air blast freezing process of the frozen food industry, which processes multiple products with variable processing rates. The analysis depicts a new, single machine-scheduling problem in which the machine can process multiple jobs concurrently, within its capacity. The machine processes independent jobs arriving at various times while incurring interruption costs when allowing the jobs to enter or leave the machine. A mixed integer linear programming (MILP) model and a heuristic algorithm are developed for scheduling, the objectives of which are to minimize the costs associated with machine activities including that of waiting to load, waiting to unload and interruption time. The heuristic algorithm demonstrates the high potential of the computational time savings by obtaining the solution within one-fifth of the mathematical model computational time.