Cnc Machine Tool Slide Rail Joint Surface Dynamic Parameters Tested And Applied Research

Digital design and manufacturing technology plays an important role increasingly in product development of high-end CNC machine tools with the development of CAD technology. The dynamic performance of machine tool is an important indicator of digital design, and the dynamic characteristics of machine tools'joint has an important impact on the dynamic performance of the whole machine, the presence of joints can lead to lower stiffness, affect the processing performance directly. Sliding guides are widely used on the CNC machine tools work as support and guiding parts, so it is significant to study the dynamic characteristics of the sliding guides'joint for the digital design of the machineThe paper raises the separation principle and methods of the sliding rails'joint using engineering equivalence principle based on the formation mechanism of dynamic stiffness and damping, simplify the joint to the equivalent single degree of freedom system, established the identification model and test system of dynamic characteristics parameter of the sliding guides'joint, introduces the testing process and identification method of the joint's parameters, get a large number of parameters and establish a characteristics database of sliding guide joint. And it analyzes the law of various factors influenced on the dynamic characteristic parameters such as sliding velocity, surface pressure, the surface materials, lubricant and other factors by single-factor test and orthogonal experiment, then study the reason from the micro-contact, tribology and lubrication theory. The results show that increasing of the sliding speed will reduce the dynamic stiffness of the joint, increasing the surface pressure and adding lubrication oil will enhance the dynamic stiffness of the joint effectively. Paper studied the law how the thickness of plastic-coat influenced on the dynamics characteristic parameters through experimental research, it shows that as the thickness increases of plastic-coat, the dynamic stiffness decreases but the damping increases, it is appropriate at 1.2 to 1.5mm for the plastic-coat in practice, and the plastic-coated guide can maintain the stability of dynamic characteristic better than the metal slide.At last, the paper discusses how to use the parameters of unit area in the whole dynamic model, proving the validity of the data got through the test and importance of joint to the dynamic characteristic of the whole structure, it is important for the accurate establishment of machine tool dynamics model and have an instructive sense for the dynamic design and optimization of machine.