scholarly journals New identification method for computer numerical control geometric errors

2021 ◽  
pp. 002029402110108
Author(s):  
Hongtao Yang ◽  
Mei Shen ◽  
Li Li ◽  
Yu Zhang ◽  
Qun Ma ◽  
...  
Keyword(s):  
Machine Tools ◽  
Geometric Error ◽  
Numerical Control ◽  
Identification Accuracy ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Cnc Machine ◽  
Identification Method ◽  
Double Ball Bar ◽  
Ball Bar

To address the problems of the low accuracy of geometric error identification and incomplete identification results of the linear axis detection of computer numerical control (CNC) machine tools, a new 21-item geometric error identification method based on double ball-bar measurement was proposed. The model between the double ball-bar reading and the geometric error term in each plane was obtained according to the three-plane arc trajectory measurement. The mathematical model of geometric error components of CNC machine tools is established, and the error fitting coefficients are solved through the beetle antennae search particle swarm optimization (BAS–PSO) algorithm, in which 21 geometric errors, including roll angle errors, were identified. Experiments were performed to compare the optimization effect of the BAS–PSO and PSO and BAS and genetic particle swarm optimization (GA–PSO) algorithms. Experimental results show that the PSO algorithm is trapped in the local optimum, and the BAS–PSO is superior to the other three algorithms in terms of convergence speed and stability, has higher identification accuracy, has better optimization performance, and is suitable for identifying the geometric error coefficient of CNC machine tools. The accuracy and validity of the identification results are verified by the comparison with the results of the individual geometric errors detected through laser interferometer experiments. The identification accuracy of the double ball-bar is below 2.7 µm. The proposed identification method is inexpensive, has a short processing time, is easy to operate, and possesses a reference value for the identification and compensation of the linear axes of machine tools.

scholarly journals Rapid Measurement and Identification Method for the Geometric Errors of CNC Machine Tools

2019 ◽  
Vol 9 (13) ◽  
pp. 2701 ◽  
Author(s):  
Li ◽  
Yang ◽  
Gao ◽  
Su ◽  
Wei ◽  
...  
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Degrees Of Freedom ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Two Dimensional ◽  
Cnc Machine ◽  
Angle Sensor ◽  
Identification Method ◽  
Measuring Machine

Error compensation technology offers a significant means for improving the geometric accuracy of CNC machine tools (MTs) as well as extending their service life. Measurement and identification are important prerequisites for error compensation. In this study, a measurement system, mainly composed of a self-developed micro-angle sensor and an L-shape standard piece, is proposed. Meanwhile, a stepwise identification method, based on an integrated error model, is established. In one measurement, four degrees-of-freedom errors, including two-dimensional displacement and two-dimensional angle of a linear guideway, can be obtained. Furthermore, in accordance with the stepwise identification method, the L-shape standard piece is placed in three different planes, so that the measurement and identification of all 21 geometric errors can be implemented. An experiment is carried out on a coordinate measuring machine (CMM) to verify the system. The residual error of the angle error, translation error and squareness error are 1.5″, 2 μm and 3.37″, respectively, and these are compared to the values detected by a Renishaw laser interferometer.

scholarly journals Global Quantitative Sensitivity Analysis and Compensation of Geometric Errors of CNC Machine Tool

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Shijie Guo ◽  
Dongsheng Zhang ◽  
Yang Xi
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tool ◽  
Machine Tools ◽  
Geometric Error ◽  
Test Method ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Cnc Machine ◽  
Open Cnc ◽  
Open Cnc System

A quantitative analysis to identify the key geometric error elements and their coupling is the prerequisite and foundation for improving the precision of machine tools. The purpose of this paper is to identify key geometric error elements and compensate for geometric errors accordingly. The geometric error model of three-axis machine tool is built on the basis of multibody system theory; and the quantitative global sensitivity analysis (GSA) model of geometric error elements is constructed by using extended Fourier amplitude sensitivity test method. The crucial geometric errors are identified; and stochastic characteristics of geometric errors are taken into consideration in the formulation of building up the compensation strategy. The validity of geometric error compensation based on sensitivity analysis is verified on a high-precision three-axis machine tool with open CNC system. The experimental results show that the average compensation rates along theX,Y, andZdirections are 59.8%, 65.5%, and 73.5%, respectively. The methods of sensitivity analysis and geometric errors compensation presented in this paper are suitable for identifying the key geometric errors and improving the precision of CNC machine tools effectively.

scholarly journals A Novel Method for the Measurement of Geometric Errors in the Linear Motion of CNC Machine Tools

2019 ◽  
Vol 9 (16) ◽  
pp. 3357 ◽  
Author(s):  
Xuan Wei ◽  
Zhikun Su ◽  
Xiaohuan Yang ◽  
Zekui Lv ◽  
Zhiming Yang ◽  
...  
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Linear Motion ◽  
Cnc Machine ◽  
Position Errors ◽  
Novel Method ◽  
Measuring Machine

In order to improve the accuracy of the linear motion of computer numerical control (CNC) machine tools, a novel method based on a new type of 1-D (1-dimensional) artifact is proposed to measure the geometric errors. Based on the properties of the displacement measurement of a revolutionary paraboloid and the angle measurement of plane mirrors, the 1-D artifact can be applied to identify position errors and angle errors. Meanwhile, the concrete 6 degrees-of-freedom error identification method is described in this paper in sufficient detail. Through measuring the 1-D artifact horizontally and vertically using the machine tool, the geometric errors can be obtained by calculating the deviation between the characteristic parameter of the 1-D artifact measured by the machine tool and that measured by a more precise method, for example, laser interferometry. Experiments were carried out on a coordinate measuring machine, and the validity and accuracy of the method were discussed by comparing the result with the identification error measured by a laser interferometer.

An Improvement Geometric Error Identification Method of CNC Machine Tool Based on Double Ball Bar

2014 ◽  
Vol 496-500 ◽  
pp. 1516-1521
Author(s):  
Qiang Cheng ◽  
Zhuo Qi ◽  
Kai Li ◽  
Li Gang Cai ◽  
Dong Lu
Keyword(s):  
Machine Tool ◽  
Recognition Algorithm ◽  
Geometric Error ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Error Identification ◽  
Double Ball Bar ◽  
Ball Bar ◽  
Error Recognition ◽  
Better Than

The double ball bar is widely used because it can quickly, easily and cost-effectively detect and evaluate the accuracy of CNC machine tools. But since the error recognition algorithm based on the double ball bar ignores the quadratic item, its recognition accuracy would be reduced. In this paper, an improved CNC verticality error and position error identification formula, combined with the machine tool error model to deduce a new error recognition model of double ball bar measurement is proposed. It can be drawn that the accuracy of the model are better than the existing methods because it keeps the second item in the derivation process of the model.

Study on Checking and Measurement of Double-Ball Bar for Thermal Error of CNC Machine Tools

2008 ◽  
Vol 375-376 ◽  
pp. 544-548 ◽  
Author(s):  
Yong Xiang Li ◽  
Yu Yao Li ◽  
Hong Tao Cao ◽  
Yong Qiao Jin ◽  
Jian Guo Yang
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Thermal Error ◽  
Error Component ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Double Ball Bar ◽  
Basic Measurement ◽  
Ball Bar ◽  
Main Factors

Thermal errors of CNC machine tools was checked and measured by double-ball bar in this paper. Mathematical model of measuring thermal error of machine tools by DBB on the principle of its basic measurement was derived. Combining it with kinematics model of machine tool, the identification law of error component parameters was established when thermal error was checked and measured by DBB. Thus, all of the thermal error component would be separated from the synthetical error. Finally, the entire analysis was provided to adjust machine tool and actualize error compensation of machine tool through grasping main factors influencing the machining precision of machine tool.

scholarly journals Study of Machining of Gears with Regular and Modified Outline Using CNC Machine Tools

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral
Keyword(s):  
Machine Tools ◽  
Coordinate Measuring Machine ◽  
Optical Microscope ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cylindrical Gears ◽  
Measuring Machine ◽  
Five Axis

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.

An Analytical C3 Continuous Local Corner Smoothing Algorithm for Four-Axis Computer Numerical Control Machine Tools

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Qin Hu ◽  
Youping Chen ◽  
Jixiang Yang ◽  
Dailin Zhang
Keyword(s):  
Machine Tools ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Smoothing Algorithm ◽  
Linear Motion ◽  
Tool Orientation ◽  
Cnc Machine ◽  
B Splines ◽  
Rotary Axes ◽  
Tip Position

Linear motion commands of multi-axis computer numerical control (CNC) machine tools need to be smoothed at the transition corners, because the velocity discontinuities at corners can result in fluctuations on machine tool motions and lead to poor surface quality. However, no research has been reported on local corner smoothing algorithm for four-axis CNC machine tools with two rotary axes by considering their special kinematic characteristics. To this end, this paper proposes an analytical C3 continuous local corner smoothing algorithm for four-axis CNC machines with two rotary axes. After coordinates transformation, the tool tip positions and tool orientations are smoothed by locally inserting specially designed three-dimensional (3D) quintic B-splines and one-dimensional (1D) quintic B-splines into the corners between linear motion segments, respectively. The smoothing algorithm guarantees C3 continuity of the tool tip position and C3 continuous synchronization of the tool orientation related to the tool tip position, through analytically evaluating control points of the inserted microsplines. The maximum error tolerances of the tool tip position and tool orientation are mathematically constrained. Experiments on an in-house developed four-axis machine verify the efficacy of the proposed algorithm, where maximal errors caused by the local corner smoothing algorithm are constrained, the synchronization of the tool orientation and the tool tip position are achieved, and the proposed C3 continuous corner smoothing algorithm has lower jerk and jounce but higher tracking and contour accuracy than C2 continuous algorithm.

Maintenance Strategy Optimization for Computer Numerical Control Machine Tools

2015 ◽  
Vol 809-810 ◽  
pp. 1504-1509 ◽  
Author(s):  
Ana Lacramioara Ungureanu ◽  
Gheorghe Stan ◽  
Paul Alin Butunoi
Keyword(s):  
Machine Tools ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Condition Based Maintenance ◽  
Financial Impact ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Maintenance Strategies ◽  
Time Period ◽  
A Company

In this paper are proposed two new approaches to maintenance strategies for Computer Numerical Control (CNC) machine tools. The analysis is done for different families of CNC machine tools from S.C. Elmet Bacau, a company specialized in aviation. In maintenance actions applied to CNC machine tools is very important to know the evolution of defects and critical state of electrical and mechanical components. The results of this analysis concludes that maintenance actions can be judged by the developing time period diagram, between failure appearance and interruptions in operation. It is also analyzed the financial impact, revealed from known maintenance strategies adopted on CNC machine tools, resulting in a positive approach of condition based maintenance.

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