**Preface to "Management of Energy and Manufacturing System"**

This reprint aims to publish recent advances and technical challenges in, as well as novel design methodologies for, energy manufacturing systems. Key to the present conception of sustainability is the capacity to meet current needs without sacrificing the future ability to do so. Maintaining this principle, which until now has been a key sustainability concept, is becoming more challenging than ever, with an increasing population rate, energy poverty, global warming, and surging demand for products and services each presenting their own unique challenges. Manufacturing is in a prime position to address this challenge, making a significant economic contribution to the global GDP and having a high influence over the environment and humanity.

These published papers can provide references for engineers, scholars, and business managers in the field of energy optimization.

> **Tangbin Xia, Ershun Pan, Rongxi Wang, Yupeng Li, and Xi Gu** *Editors*

#### *Article* **Research on Machining Workshop Batch Scheduling Incorporating the Completion Time and Non-Processing Energy Consumption Considering Product Structure**

**Nailiang Li \* and Caihong Feng**

> Department of Industrial Engineering, School of Mines, China University of Mining and Technology, Xuzhou 221116, China; TS19020220A31@cumt.edu.cn **\***

 Correspondence: cumt\_lnl@126.com

**Abstract:** Energy-saving scheduling is a well-known issue in the manufacturing system. The flexibility of the workshop increases the difficulty of scheduling. In the workshop schedule, considering the collaborative optimization of multi-level structure product production and energy consumption has certain practical significance. The process sequence of parts and components should be consistent with the assembly sequence. Additionally, the non-production energy consumption (NPEC) (such as the energy consumption of workpiece handling, equipment standby, and workpiece conversion) generated by the auxiliary machining operations, which make up the majority of the total energy consumption, should not be ignored. A sub-batch priority is set according to the upper and lower coupling relationship in the product structure. A bi-objective batch scheduling model that minimizes the total energy consumption and the total completion time is developed, and the multi-objective gray wolf optimizer (MOGWO) is employed as the solution to obtain the optimal schedule scheme. A case study is performed to demonstrate the potential possibilities concerning NPEC in regard to reducing the total energy consumption and to show the effectiveness of the algorithm. Compared with the traditional optimization model, the joint optimization of NPEC and PEC can reduce the energy consumption of standby and handling by 9.95% and 22.28%, respectively.

**Keywords:** multi-level structure; non-production energy consumption (NPEC); sub-batch priority; multi-objective gray wolf optimizer (MOGWO)
