Review of Automated Inspection, Equipment Monitoring and Optimization of Manufacturing Zezhong Wang School of Engineering and Applied Science Aston University Birmingham, UK 180213694@aston.ac.uk Gareth Thomson School of Engineering and Applied Science Aston University Birmingham, UK G.A.THOMSON@aston.ac.uk Yuchun Xu School of Engineering and Applied Science Aston University Birmingham, UK y.xu16@aston.ac.uk Xianghong Ma School of Engineering and Applied Science Aston University Birmingham, UK x.ma@aston.ac.uk Abstract—Modern manufacturing has made huge progress in production efficiency. However, the status of the production equipment deteriorates during manufacturing, and their condition can then affect the quality of products and total production cost. When viable, maintenance, remanufacturing and replacement should be carried out for such equipment to reduce the total production cost. However, many processes, for example, inspection and manufacturing planning are carried out by a human. In the era of Industry 4.0, an automated production planning with automated condition monitoring, equipment inspection and maintenance planning is desired. In this article, the literature on related topics is reviewed. The state of the art in this study helps to improve the performance of production lines in manufacturing. Keywords—smart manufacturing, production planning, maintenance planning, automated inspection, diagnostic and prognostic, optimization, process control I. INTRODUCTION Production lines have improved the efficiency of manufacturing, however, the status of the production equipment deteriorates during high-efficiency mass production. The deterioration affects the quality of the products. Therefore, it is necessary to maintain the status of the equipment, which can be done by maintenance, remanufacturing or replacement of the tools. However, the normal maintenance interrupts the manufacturing schedule, so how to make an optimised total manufacturing plan is very important for modern production. So far, there are many kinds of maintenance strategy: breakdown maintenance, time-based maintenance, PM (preventive maintenance), CBM (Condition-based Maintenance), TPM (Total Productive Maintenance) [1] and maintenance 4.0 [2]. The current maintenance inevitably interrupts the production, which is a waste of time and resource. The researchers are managing to improve the total production plan by optimizing the maintenance plan. Inspection of the equipment and condition monitoring of the equipment is important to manufacturing. AS (Allocation Strategy) and PS (Parametric Strategy) are currently the main methods of inspection planning [3]. However, in the context of Industry 4.0, the method should be combined as the AS-PS method. With the development of sensing technology, the TCM (Tool Condition Monitoring) is more real-time and precise, the research trend nowadays is to fuse the sensor data to make an accurate evaluation of current state and prediction of the useful life of the equipment. There are 2 main questions to be answered in this review article: how to monitor the status of the equipment optimally? How to make the maintenance plan without interrupting the production or at the least cost? The reviewed research literature is searched in Scopus, ScienceDirect and ProQuest databases. Since the diagnostic and prognostic methods are limited to the development of sensors and heuristic algorithms, the Literature review of this part is limited from the 2000s to 2020. The key words ‘tool wear’ ‘manufacturing’ ‘diagnostic’ ‘prognostic’ are used to search for related literature in Scopus, ScienceDirect and ProQuest databases (see Fig. 1). For optimisation of manufacturing processes, keywords ‘manufacturing optimisation’, ‘maintenance plan’, ‘quality inspection’ and ‘tool condition monitoring’ were used to find relevant journal articles. All the journals with the most impact indicator were searched. The number of literature in recent 30 years showed an increasing trend of this topic (see Fig. 2). The article is organized like this: in section 2, the methods of tool condition monitoring are reviewed. Product quality inspection and inspection planning are reviewed in section 3. The methods of diagnostic and prognostic to determine the equipment state are introduced in section 4. The optimization Fig. 1. The number of literature on tool wear diagnostic and prognostic in recent 20 years