Energy Consumption Evaluation in Stamping Workshops via a Discrete Event Simulation-Based Approach

Stamping is employed in a wide range of applications in industry, which is composed of discrete flow energy-intensive processes. Durations of stamping activities are much shorter than that of mold changing and transportation, which makes energy consumption in stamping workshops greatly affected by the production scheme and the proportion of transportation volume. Different from machining that has been widely discussed, there is less research on energy saving in stamping workshops. This paper aims to evaluate the energy consumption of stamping on the workshop level. A theoretical model and a discrete event simulation model were developed based on energy flow and material flow in the workshop. The theoretical model was used to calculate each component of energy consumption based on production-related data. The simulation model was used to predict the overall energy required in the workshop when subjected to changes in its production conditions. Impacts of influence factors, including machine failure rate, proportion of transportation volume, and production scheme on energy consumption, makespan, and machine utilization rates, were studied to find opportunities for energy reduction and production efficiency improvement. Finally, a case study of a stamping workshop for forklifts validated the proposed approach, and  optimization measures were suggested, implemented, and verified. Results have found that under the same production scheme (suppose each press has the same failure rate), the balance between energy use and makespan was achieved when the proportion of transportation volume was 1/2. This simulation-based approach provides a useful tool for evaluating and reducing energy consumption and helps operators to perform energy-saving actions in stamping workshops.