Abstract : This paper introduces a hydraulic system for manufacturing a novel high-efficiency and energy-saving device—an automatic finned tube welding machine. The system uses two pairs of clamping cylinders and one pulling cylinder to achieve the step-feeding function, while the other four pairs of cylinders perform the clamping and pushing welding actions on the fins and tubes. Keywords: Welding machine, hydraulic stepping system, finned tube 1 Introduction Finned tubes are a new type of high-efficiency heat exchanger, which uses resistance welding to weld fins (heat sinks) equidistantly onto a seamless tube. This exchanger has advantages such as high pressure resistance, high thermal efficiency, and a compact and aesthetically pleasing appearance. The operation of the automatic finned tube welding machine mainly consists of two parts: a step-feeding section and a tube welding section. The working procedure is as follows: Feeding sheet → [Sheet clamping/tube clamping] → Sheet push welding → Sheet return → [Sheet release/close release] → Sheet push return → Small slide clamping → Pulling cylinder pulling (stepping) → Large slide clamping → Small slide release → Pulling cylinder reset → Large slide release 2. Stepping feeding hydraulic system Currently, the commonly used methods for achieving stepping in engineering are mainly mechanical stepping systems, stepper motors, and hydraulic stepping cylinders. These three stepping forms each have their own disadvantages: mechanical stepping systems have a relatively complex structure, the stepping distance is not easily adjusted accurately, and the cumulative stepping error is large. Although stepper motors have a wide range of applications, their power is relatively limited and cannot achieve high-power actions. Comparing various hydraulic stepping cylinders, the simplest stepping cylinder is an electro-hydraulic stepping cylinder. Although this type of stepping cylinder can achieve adjustable stepping distance, small cumulative error, and accurate stepping distance, the stepping stroke that this type of stepping cylinder can achieve is very limited, making it unsuitable for long-distance stepping requirements. To reduce costs, the entire machine utilizes hydraulic transmission; therefore, a novel hydraulic stepping system was designed. [b][align=center]For details, please click: Hydraulic System Design of Automatic Ribbed Tube Welding Machine[/align][/b]