Innovation of CNC Machining Technology for the Rod Head of the Hydraulic Cylinder of an Excavator: Achieving Breakthroughs in Complex Surfaces through Multi-axis Linkage

Recently, a construction machinery manufacturing enterprise has overcome the challenge of precision machining of the rod head of the hydraulic cylinder of excavators. It has achieved the integrated molding of complex curved surfaces at the millimeter level through a seven-axis联动 CNC machine tool. This technology breaks through the geometric limitations of traditional turning processes, making the layout of the sealing groove and oil passage of the rod head more compact. It has been applied to large-tonnage mining excavators. "The core of the CNC machining of the rod head of the hydraulic cylinder of excavators lies in the multi-axis coordinated control." The process director demonstrated the 3D model. The traditional rod head requires separate welding and machining, while the new solution uses a whole piece of alloy steel billet and realizes the continuous milling of the spiral oil passage through the interpolation algorithm of the tilting axis. "All features are completed in a single clamping, and the coaxiality accuracy reaches 0.015mm." In order to overcome the problem of vibration in deep hole machining, the team has developed a dual-damping vibration reduction system. A piezoelectric ceramic sensor is installed inside the spindle of the machine tool to monitor the vibration frequency in real time, and it cooperates with the adaptive feed algorithm to adjust the cutting parameters. "This is equivalent to installing a 'dynamic stabilizer' for the tool." The inspection report shows that the surface roughness of the inner hole of the new rod head reaches Ra0.4μm, which is 70% higher than that of the traditional process. A certain mining equipment operator has feedback that the hydraulic cylinder using the new process has a 85% reduction in external leakage during the 3000-hour high-load test, and the oil change cycle has been extended to 500 hours. "Especially the sealing performance of the rod head has significantly reduced the maintenance cost." The customer's technical director said that the attendance rate of the equipment has increased by 12 percentage points as a result. The enterprise has established a complete machining parameter library for the rod head of the hydraulic cylinder of excavators, covering the requirements of models ranging from 20 to 100 tons. The R&D team revealed that it is developing an online inspection system based on machine vision, which can achieve 100% full inspection of key dimensions in the future. "This will promote the intelligent transformation of the CNC machining of the rod head of the hydraulic cylinder of excavators." With the industrial application of this technology, the localization rate of core components of high-end excavators in China is expected to exceed 90%, providing more reliable equipment support for scenarios such as mining and infrastructure construction projects.