Method for assessing reliability of technology for large numerical control machine

Abstract

The invention provides a method for assessing a technology for a large numerical control machine, comprising the following steps: obtaining frequency response function curve of the large numerical control machine through structure composition dynamic stiffness experiments; employing nonlinear least square method to identify dynamical parameter through curve least square fitting; establishing a non-linear dynamical model of machining process of the numerical control machine by identifying machining technical parameters of cutting force dynamic model in a cutting force experiment; then employing the method of random sampling to simulate tooling motion trail and calculating the number of failpoints to work out probability of technological reliability.With the method of the invention, technological reliability of the numerical control machine can be accurately assessed according to the existing structural characteristics, processing technic characteristics and processing conditions of the large numerical control machine, so that accuracy and high efficiency of technological reliability assessment can be improved and a new method is provided for on-line reliability assessment of the large numerical control machine.

Description

technical field [0001] The invention relates to the technical field of process reliability evaluation of numerical control equipment, in particular to an evaluation method for process reliability of large-scale numerical control machine tools. Background technique [0002] The process reliability of CNC machine tool refers to the performance of maintaining the processing quality and realizing the process determined by the use of the machine tool within the specified time limit and specified productivity. That is to say, it is not only necessary to ensure the initial high precision of the CNC machine tool, but also to maintain its accuracy, efficiency and cost within the specified service life. The process reliability of the CNC machine tool focuses on the maintenance of the function and technical performance of the CNC machine tool during the processing sex. The process reliability evaluation technology of CNC machine tools is one of the necessary means to quantitatively co...

AI Technical Summary

Problems solved by technology

[0005] In fact, when a large CNC machine tool is working, a large number of mechanical, hydraulic, pneumatic, electrical and electronic mechanisms and components interact with each other, because the process system (including CNC machine tools, tools, fixtures and blanks) is affected by internal factors (cutting force And its torque, friction, vibration, heating of process system components, etc.) and external factors (ambient temperature, vibration of adjacent equipment, voltage fluctuations, air humidity and pollution, operator intervention, etc.), the process system components will be elastic Deformation, wear, vibration, thermal deformation, changes in the performance parameters of the process system (such as geometric accuracy, motion accuracy, stiffness, etc.), the processing accuracy is reduced, resulting in deterioration of processing quality, in other words, the process reliability of CNC machine tools is reduced

However, the existing reliability evaluation technology of CNC machine tools does not consider the process reliability changes caused by the performance changes of the process system, which leads to the conservative use of end users to operate CNC machine tools, thereby reducing the production efficiency and processing quality of CNC machine tools

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