Industrial Robots Support the Digital Factory

Industrial robots, as manufacturing equipment integrating numerous functions such as precise calculation, joint motion, and visual recognition for industrial applications, are naturally the main application equipment in digital factories.

2014 was the inaugural year for the widespread development of robots in China. The application of robots in the field of intelligent manufacturing is not simply about replacing humans with machines; it will bring tremendous changes to production forms and manufacturing methods. Traditional manufacturing methods from the past must also adapt to the new development trends in robot applications, gradually transitioning to the entirely new manufacturing platforms of intelligent manufacturing, smart factories, and digital factories. Simultaneously, with the continuous development of technology, industrial robots, in terms of functionality, performance, cost, and other aspects, are fully capable of undertaking the mission of supporting this transformation in manufacturing models.

Application Status and Development Trends

The application of robots in digital factories is closely linked to the entire MES layer and even the broader meaning of informatization within an enterprise. Currently, most general manufacturing enterprises in China have not yet reached this level. Their robot applications are mostly isolated, primarily in processes such as welding, grinding, spraying, and material handling, and have not yet reached a level supported by digitalization. They are merely isolated applications on single pieces of equipment, not connected with the enterprise's overall informatization applications, and do not yet meet the requirements of a digital factory.

In China, new manufacturing platform systems that can be called "digital factories" or "digital workshops" are mainly concentrated in the automotive manufacturing sector. Within the automotive industry, foreign-invested and joint venture enterprises have a relatively high degree of digitalization. The main form of realization for a digital factory is through MES (Manufacturing Execution System), which connects upstream ERP production management systems and downstream equipment systems. Currently, digital factories in automotive enterprises have basically achieved build-to-order production. The orders received by automotive plants now are for small batches and multiple varieties. Orders for cars with different models, specifications, and colors are simultaneously fed into the system via ERP. After automatic analysis and processing by the system, they are allocated to supply departments, equipment departments, and production management departments. Then, the system delivers the corresponding parts, components, and tools to each workstation on time according to the production schedule.

Throughout the entire process from body welding to final vehicle assembly, cars of different models, specifications, and colors can be produced simultaneously on the same production line. Currently, automotive manufacturers can operate using this production model. This model already meets the basic requirements of a digital factory. It can record every piece of production data from the equipment, incorporate it into the ERP, forming a complete production and equipment report. Information for every component of each car is recorded in the system, enabling full traceability. Subsequently, if a problem occurs with any component of any vehicle, the source of the problem can be immediately identified using the system through the information code on those components: who supplied the component, where the problem occurred, who installed it—all information is clear.

The application of robots is indispensable in the digital factories of automotive enterprises, primarily performing two tasks: body welding and spraying. Robots are also used for some parts assembly and inspection, but the scale, quantity, and extent of use are not as high as the former two. Domestic automotive enterprises basically rely on humans for assembly tasks and have not achieved large-scale robot assembly.

In a digital factory, a robot is a standard component or piece of equipment; robot repair is not for a special component or device. Digital factories particularly emphasize the standardization of equipment and technology. In a digital factory, a robot is first defined as a standard piece of equipment or component; its constituent parts, the control system and servo motors, are also standard products. What differs is their software. Certain types of robot controllers can also connect to the upper-level control management system via unified fieldbus methods such as EtherCAT.

Robots and the digital factory control management system are connected via Ethernet, and tasks are also assigned to robots via Ethernet. The robots then complete the corresponding processes according to the program specified by the task.

Collaborative and Integrated Manufacturing

What role the robot itself can play, such as whether its various movements can meet production process requirements, requires system integrators to solve this problem. Unlike ordinary general equipment, robots cannot be used immediately after purchase. Before being put into operation, they must be tightly integrated with the production process, production technology, front-end and back-end equipment, and the action links of the process to achieve the expected effect.

As an intelligent automation device, robots need to collaborate and integrate with other automation equipment. First, the issue of standardization needs to be addressed. The equipment in a digital factory is not provided by a single company. Robots are often not of a single brand either, and the situation becomes even more complex when adding peripheral equipment and instruments. To make them work together normally and smoothly, standardized requirements must be imposed on them, such as whether a unified Ethernet standard interface is adopted. If standards are unified, each piece of equipment can be conveniently connected to the digital factory's control system. If some equipment uses different buses or other technical protocols, it will increase costs in later applications, forcing the use of other technical means to convert these different buses to the same bus standard. Therefore, in the initial stages of establishing a digital factory, considering the standardization of equipment, including robots, in advance can greatly save later modification costs, avoiding the need for additional financial and effort investment to solve communication issues between different standards.

When controlling and managing robots, they can be treated as general equipment. There are two main categories of equipment in a digital factory: intelligent equipment and ordinary equipment. Robots are one type of intelligent equipment. Regardless of the type of equipment, a digital factory has a complete management system. All equipment is linked together via a coordinating bus and connected to the management system. The operating status of each piece of equipment can be monitored and detected instantly and dynamically. Compared with the scheduled inspections and maintenance of traditional factories, this is a huge advancement. For example, in a traditional factory, equipment is only discovered and sent for repair when a problem occurs, or rigid maintenance schedules like minor maintenance every six months and major overhaul every year are enforced even when no problems are apparent. In a digital factory, it is not this kind of mechanical maintenance and upkeep. It is dynamic maintenance; indicators and conditions of each piece of equipment, including robots, are transmitted as data to the system in real-time. The system analyzes and detects this data. Once any data shows a problem, the system can intervene or alarm immediately, feeding back to the maintenance department to make a maintenance plan in advance. This evolves equipment maintenance from scheduled to dynamic. Intelligent equipment, including robots, joining this dynamic maintenance system will greatly increase efficiency and convenience. For instance, the lubricating oil inside a robot must be maintained at a certain level, which requires detection. However, the uneven workload intensity brought by flexible production makes scheduled detection difficult to yield accurate results and may even pose risks. Now, with real-time detection, the temperature, viscosity, and remaining level of the grease are promptly discovered, and the system decides whether replacement or replenishment is needed.

The Soul of the Digital Factory is People

In traditional factories, daily management and production management, including equipment management, financial management, and supply management, are carried out through people. In digital factories, this becomes digital management supported by software. However, the level of this management still depends on the rationality and optimization of the enterprise's manual management processes.

Therefore, the idea of relying on technological means to optimize unresolved management problems is wrong and unworkable. For an enterprise, what the planning process is, what the production process is, what the financial process is, and what the technical equipment process is cannot be properly solved by a standard software package.

In a digital factory, the ultimate decisive factor, or its core, is still people, not equipment or software. Therefore, what plays the decisive role in the level of digital factory management is the enterprise manager's definition and design of the enterprise management processes. From this, it can be seen that the optimization and perfection of management philosophy and processes come first, followed by a high level of digital management for the entire factory. In this sense, it is a realization path for traditional enterprise management. Previously, management was presented in a discrete manner through people, processes, paper, or other related means. After digitalization, it is presented in an integrated, three-dimensional manner through informatization and corresponding software. This liberates people from simple, repetitive labor.

Documentation Archive Number: 7130. Content organized from the old site database.