With continuous societal progress and evolving market demands, the market has shifted from a mass-market, single-sector model to a diversified one. Furthermore, labor supply has been declining year by year, while labor costs have been rising. This transformation has led to increasingly fierce market competition and shrinking profit margins for businesses. Consequently, many manufacturing companies are choosing automated production to replace manual labor, aiming to improve product quality and production efficiency, ensuring their products are high-quality yet affordable, and securing a place in the market. However, many companies currently face numerous challenges in adopting automated production methods. Determining the rationality of equipment functions, planning equipment layout, achieving production line balance, and improving equipment utilization have all become critical issues that urgently need to be addressed.
1. Lean Manufacturing and Lean Automation
1.1 Lean Manufacturing and Automation
The Toyota Production System is known as TPS. In 1985, MIT named it Lean Production. Lean Production has two main pillars: Just-in-Time (JIT) production and automation. The components of Lean Production are shown in Figure 1.
Figure 1. Composition of Lean Production
Automated production can achieve higher product quality and reduce manpower requirements. The primary premise of automated production is to produce 100% qualified products. During the production process, the equipment can automatically detect equipment malfunctions and product quality abnormalities, and can automatically stop the process, ensuring that defective products do not flow to the next process. Furthermore, because the equipment can stop automatically, there is no need for dedicated personnel to constantly monitor its operation, thus achieving labor-saving improvements.
1.2 Lean Automation
Lean automated production, derived from the principles of lean manufacturing, integrates JIT, IE, 5S, and other concepts and improvement methods into automated production, aligning production operations with the production cycle. Through IE techniques such as process analysis, job analysis, and motion analysis, waste is reduced and production efficiency is improved. Combined with technologies like quick changeover, information visualization, and 6σ, product quality is enhanced, adapting to flexible production. Optimizing continuous flow at the automation level achieves comprehensive lean automation of production. Further enhanced by big data, IoT, and other information technologies, the factory can then enter the realm of smart manufacturing .
2. Lean Automation and Intelligent Manufacturing
2.1 Implementation of Lean Automation
Under the premise of ensuring production safety, the automation implementation is divided into 4 major modules and 23 sub-items. The 4 major modules are tool automation, process automation, production line automation, and factory automation.
2.1.1 Tool Automation
Tool automation primarily aims to reduce the workload of operators by using simple auxiliary tools to complete production tasks, shifting from "human work" to "tool work." The main sub-items are as follows:
1. Tooling and instrumentation: general-purpose tools are processed into specialized tools for ease of use.
2. Processing automation: Manual operations are replaced by small electric or pneumatic equipment.
3. Fixed position: Fixed the usage position of props and small equipment.
4. Automated conveying: The work of props and small equipment is separated from the work of people.
5. Reset to original position: After the operation is completed, the props and small equipment can be returned to their original positions.
2.1.2 Process Automation
Process automation primarily focuses on separating human and machine operations. Operators only need to clamp and retrieve workpieces, creating conditions for one person to operate multiple machines and reducing the need for human labor. It represents a shift from "human work" to "machine work." Furthermore, because machine error rates are lower than manual operations, product quality is significantly improved. The main sub-items are as follows, and the process automation level is shown in Figure 2:
1. Automatic clamping fixture: The position of the workpiece is fixed by a clamping device.
2. Automated processing: The processing of workpieces is carried out automatically by means of electric, hydraulic, or pneumatic power.
3. Automatic conveying: The transfer of workpieces and accessories is carried out automatically by means of electric, hydraulic, or pneumatic power.
4. Automatic stop: The machining part of the machine automatically stops moving after the workpiece is finished.
5. Automatic home position reset: The machine processing part automatically returns to its original position after processing stops.
6. Automatic pop-up: The workpiece will automatically pop up after processing is completed.
7. Automatic transport: After the workpiece is ejected, it is automatically transported to the next work station.
8. Automatic measurement: All workpieces are automatically measured after processing.
9. Automatic installation: The installation of workpiece accessories is carried out automatically by electric, hydraulic, or pneumatic means.
10. Automatic start: After the workpiece is clamped, the machine automatically starts the machining program within the process.
Figure 2. Automation Level of Process
2.1.3 Production line automation
The goal of integrating safety, tool automation, and process automation is to reduce manufacturing costs and improve product quality, elevating production from a "point" or "line" level to a "surface" level. The primary upgrade involves production line automation, with the main sub-items listed below. A demonstration diagram of production line automation is shown in Figure 3.
1. Cycle time: Regardless of the type of workpiece, it must be manufactured within a specified time.
2. Front and back control: The equipment will only operate if there is a workpiece in the previous process and no workpiece in the subsequent process.
3. Single-piece flow: Only one workpiece is in flow within each process.
4. Pilot system: Some equipment has a control and regulation system installed.
5. U-shaped production line: The equipment layout is arranged in a U-shape according to the process.
Figure 3. Demonstration diagram of production line automation
2.1.4 Factory Automation
By integrating "points," "lines," and "surfaces," the production line has achieved lean automation. The next step is to achieve lean automation across the entire factory, with the following main sub-items:
1. Goods ready for delivery: Shipments include an anomaly detection system.
2. Visual management: The production status of the factory can be understood through visual means.
3. Large-scale office model: Collaborate with relevant departments to quickly resolve issues.
2.2 Lean Automation Equipment Development
The following six basic principles must be met when developing lean automation equipment.
1. The equipment is highly mobile, with neat and flexible pipeline distribution. The connectors can be plugged in and used immediately, facilitating connection with upper and lower workstations.
2. The equipment is highly stable, produces high-quality workpieces, and is stable with few malfunctions.
3. The equipment has a high utilization rate, is dedicated to its specific purpose, has a short idle running time, high synchronization of operations, and no unnecessary additional functions, thus meeting the established production capacity requirements without excessive production capacity waste.
4. The equipment is easy to operate and debug. The feeding and unloading are in the same position. The height of the workbench is convenient for employees to operate, minimizing the working range of people. The height is highly consistent. The front process exits and the back process enters. The narrow and deep design facilitates connection. There is a dedicated maintenance and debugging "window".
5. The conveyor belt is a continuous type, and the employee's work is synchronized with the conveyor. The working time is within the range of the ratio of the conveyor line pitch to the line speed. The line speed can be set according to the production distance. There are "transfer zones" on both sides of the pitch line. There are start and stop switches for the line operation in the employee's work area, and there are sound and visual alarms when the line movement changes.
6. The equipment is highly flexible. General-purpose equipment can become specialized equipment by adding special components. Specialized equipment can produce different models of products by replacing different components, or increase production capacity. The equipment can change its own function by modifying some components.
2.3 Integration of Lean Automation and Intelligent Manufacturing
Intelligent manufacturing is a revolutionary integration, reshaping, and innovation of enterprises and value chains across multiple dimensions through new technologies (big data, IoT, cloud computing, etc.). It enables all participants in the entire industry chain (R&D, production, supply, sales, and usage) to participate in the entire process from product development to sales and even the end of the product lifecycle within a flexible, autonomous, and open collaborative system. Manufacturing enterprises can enter the ranks of intelligent manufacturing by implementing lean automated production methods, coupled with information technologies such as MES, ERP, CRM, and PLM in the Industry 3.0 era, and supplemented by new technologies such as big data, IoT, and cloud computing.
3. Summary
With the development of machinery and information technology, the popularization of industrial engineering and lean production knowledge, and the emergence of intelligent manufacturing , lean automated production methods have gradually penetrated the manufacturing industry, playing a significant role in promoting product manufacturing. Manufacturing enterprises can leverage this opportunity to gradually adopt lean automated production methods, enhance production efficiency, improve product quality, and cope with a complex and ever-changing market. Furthermore, they can use this as a stepping stone to achieve intelligent manufacturing in their factories by leveraging new technologies such as big data, the Internet of Things, and cloud computing. This will enhance the brand awareness and corporate image of their products, allowing them to remain resilient in the face of changing times.
