# Orbital-Based Automatic Multi-Layer Multi-Pass Welding Equipment for Small Assembly Plates
## 1 Introduction  
With the development of intelligent technology, the manufacturing industry has entered a stage of deep integration of informatization, automation, and intelligence, and international research and application of automation equipment have become more widespread [1; 2; 3; 4; 5; 6]. To address the issue of insufficient demographic dividends, the manufacturing industry urgently needs to develop corresponding automation equipment to achieve the ultimate goal of enhancing production performance and reducing labor costs in the technical field. So far, due to the advent of diversified transformation in the manufacturing industry and the proposal of Industry 4.0, the processes of intelligent manufacturing, industrial internet, and equipment customization have accelerated. Automatic welding equipment with different functions and application scenarios designed through various methods is being initially applied [7; 8; 9; 10; 11]. For example, applications include the design and development of automatic welding equipment for pipe welding [12], intelligent handheldwelding devices [13], the design of fixtures for automatic welding equipment [14], and robots developed and applied for automatic welding of box girders and construction steel structures [15]. Small assembly plates serve as fundamental component units in the shipbuilding process. Their simple structure and high demand make them highly suitable for mass production using rail-mounted welding robotic arms equipped with automated welding technology. Traditionally, the processing of small assembly plates relies on manual welding, which results in high labor costs, significant challenges in quality control, prolonged welding cycles, and low production efficiency. This reflects the current state of plate processing in shipyards both domestically and internationally. As labor shortages and the aforementioned technical challenges accelerate the manufacturing industry's transition to \"machine substitution,\" the era of automated welding has arrived. The traditional production model of one person per workstation will gradually shift to an automated production model of one person overseeing an entire production line. Compared to traditional methods, equipment equipped with welding robotic arms offers faster welding speeds and higher weld seam quality. The use of automated programming technology also allows operators to stay away from harsh production environments. Therefore, in the context of manufacturing process transformation, designing a rail-mounted automatic welding device capable of multi-layer and multi-pass welding serves as a pioneer for intelligent, large-scale, and continuous production of structural components, possessing significant application value. This equipment integrates mechanical design technology, simulation analysis technology, welding technology, robotics, and automatic processing technology, enabling efficient and precise welding operations. It is a key piece of equipment in intelligent manufacturing both domestically and internationally [16]. By moving along a predetermined track and carrying the necessary functional modules to weld workpieces, the device achieves stable welding quality and production efficiency. However, there are currently few comprehensive studies or available design and analysis schemes for rail-mounted automatic welding equipment utilizing welding robotic arms. Completing the design and analysis of this equipment can provide a theoretical foundation and important data support for subsequent research and production work. The mechanical structure of the rail-mounted automatic welding equipment designed and developed in this paper includes specialized fixing mechanisms, installation and bearing mechanisms, quick-plug mechanisms, and moving mechanisms. The finite element analysis of these mechanisms and equipment testing presented in the following sections provide a basis for further practical applications. The remainder of this paper is organized as follows.