Five-axis machine tool volumetric and geometric error reduction by indirect geometric calibration and lookup tables

2021 ◽  
pp. 1-25
Author(s):  
Sareh Esmaeili ◽  
René Mayer ◽  
Mark Sanders ◽  
Philipp Dahlem ◽  
Kanglin Xing
Keyword(s):  
Machine Tool ◽  
Experimental Tests ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Cnc Machine ◽  
Machine Error ◽  
Working Volume ◽  
Volumetric Errors ◽  
Lookup Tables ◽  
Five Axis

Abstract Modern CNC machine tools provide lookup tables to enhance the machine tool's precision but the generation of table entries can be a demanding task. In this paper, the coefficients of the 25 cubic polynomial functions used to generate the LUTs entries for a five-axis machine tool are obtained by solving a linear system incorporating a Vandermonde expansion of the nominal control jacobian. The necessary volumetric errors within the working volume are predicted from machine's geometric errors estimated by the indirect error identification method based on the on-machine touch probing measurement of a reconfigurable uncalibrated master ball artefact (RUMBA). The proposed scheme is applied to a small Mitsubishi M730 CNC machine. Two different error models are used for modeling the erroneous machine tool, one estimating mainly inter-axis errors and the other including numerous intra-axis errors. The table-based compensation is validated through additional on-machine measurements. Experimental tests demonstrate a significant reduction in volumetric errors and in the effective machine error parameters. The LUTs reduce most of the dominant machine error parameters. It is concluded that although being effective in correcting some geometric errors, the generated LUTs cannot compensate some axis misalignments such as EB(OX)A and EB(OX)Z. The Root Mean Square of the translational volumetric errors are improved from 87.3, 75.4 and 71.5 µm down to 24.8, 18.8 and 22.1 µm in the X, Y and Z directions, respectively.

Sensitivity Analysis of Geometric Errors for Five-Axis CNC Machine Tool Based on Multi-Body System Theory

2012 ◽  
Vol 271-272 ◽  
pp. 493-497
Author(s):  
Wei Qing Wang ◽  
Huan Qin Wu
Keyword(s):  
System Theory ◽  
Sensitivity Analysis ◽  
Machine Tool ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Body System ◽  
Cnc Machine ◽  
Multi Body ◽  
Five Axis

Abstract: In order to determine that the effect of geometric error to the machining accuracy is an important premise for the error compensation, a sensitivity analysis method of geometric error is presented based on multi-body system theory in this paper. An accuracy model of five-axis machine tool is established based on multi-body system theory, and with 37 geometric errors obtained through experimental verification, key error sources affecting the machining accuracy are finally identified by sensitivity analysis. The analysis result shows that the presented method can identify the important geometric errors having large influence on volumetric error of machine tool and is of help to improve the accuracy of machine tool economically.

Research on High Performance Direct-Driving Motor Applied to Swivel Spindle Head

2014 ◽  
Vol 701-702 ◽  
pp. 874-878
Author(s):  
Shao Hsien Chen ◽  
Chin Mou Hsu ◽  
Kuo Lin Chiu ◽  
Chu Peng Chan
Keyword(s):  
Renewable Energy ◽  
Machine Tool ◽  
Machine Tools ◽  
High Performance ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Positional Accuracy ◽  
Maximum Torque ◽  
Five Axis

Swivel spindle head is a key component used in five-axis machine tool of high performance and is of great importance in application and design. Nowadays, more and more components are manufactured by high performance multi-axis CNC machine tools, such as components of spaceflight, renewable energy and automobile, etc. Therefore, high performance machine tools of multiple axes are more and more urgently demanded, while Swivel spindle head is one of the most important components for a multi-axis machine tool. Hence, Swivel spindle head is one of the key to developers multi-axis machine tool . The study explores the highly responsive direct-driving motor able to drive the spindle head to rotate with multi-driving rotary technology. The dual-driving motor rotates via multi-driving units, generates torsion that magnifies and eliminates its clearance, and then drives the spindle head to rotate. Results of the test show that the completed machine tool can meet the standards of dual axis rotary head with high preformation in, no matter, speed, distance, positional accuracy, repeated accuracy or maximum torque, etc.

Geometric accuracy allocation for multi-axis CNC machine tools based on sensitivity analysis and reliability theory

2014 ◽  
Vol 229 (6) ◽  
pp. 1134-1149 ◽  
Author(s):  
Qiang Cheng ◽  
Ziling Zhang ◽  
Guojun Zhang ◽  
Peihua Gu ◽  
Ligang Cai
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tool ◽  
Operating Conditions ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Volumetric Error ◽  
The Cost ◽  
Five Axis

Machining accuracy of a machine tool is influenced by geometric errors produced by each part and component. Different errors have varying influence on the machining accuracy of a tool. The aim of this study is to optimize errors to get a desired performance for a numerical control machine tool. Applying multi-body system theory, a volumetric error model was constructed to track and compensate effects of errors during operation of the machine, and to relate the functional specifications on volumetric accuracy to the permissible errors on the joints and links of the machine. Error sensitivity analysis was used to identify the influence of different errors (especially the errors which have large influences) on volumetric error. Based on First Order and Second Moment theory, an error allocation approach was developed to optimize allocation of manufacturing and assembly tolerances along with specifying the operating conditions to determine the optimal level of these errors so that the cost of controlling them and the cost of failure to meet the specifications is minimized. The approach developed was implemented in software and an example of the geometric errors budgeting for a five-axis machine was discussed. It is identified that the different optimal standard deviations reflect the cost-weighted influences of the respective parameters in the equations of the functional requirements. This study suggests that it is possible to determine the coupling relationships between these errors and optimize the allowable error budgeting between these sources.

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 Impact of Model Complexity in the Monitoring of Machine Tools Condition Using Volumetric Errors

2020 ◽  
Vol 14 (3) ◽  
pp. 369-379
Author(s):  
Kanglin Xing ◽  
◽  
J. R. R. Mayer ◽  
Sofiane Achiche
Keyword(s):  
Machine Tool ◽  
Recognition Rate ◽  
Error Model ◽  
Model Complexity ◽  
Model Parameters ◽  
Machine Error ◽  
Error Models ◽  
Tool Condition ◽  
Volumetric Errors ◽  
Five Axis

The scale and master ball artefact (SAMBA) method allows estimating the inter- and intra-axis error parameters as well as volumetric errors (VEs) of a five-axis machine tool by using simple ball artefacts and the machine tool’s own touch-trigger probe. The SAMBA method can use two different machine error models named after the number of model parameters, i.e., the “13” and “84” machine error models, to estimate the VEs. In this study, we compare these two machine error models when using VE vector directions and values for monitoring the machine tool condition for three cases of machine malfunctions: 1) a C-axis encoder fault, 2) an induced X-axis linear positioning error, and 3) an induced straightness error simulated fault. The results show that the “13” machine error model produces more focused concentrated VE directions but smaller VE values when compared with the “84” machine error model; furthermore, although both models can recognize the three faults and are effective in monitoring the machine tool condition, the “13” machine error model achieves a better recognition rate of the machine condition. This paper provides guidelines for selecting machine error models for the SAMBA method when using VEs to monitor the machine tool condition.

The Impact of Different Direct-Driving Motor Design on Swivel Spindle Head

2015 ◽  
Vol 789-790 ◽  
pp. 791-794
Author(s):  
Shao Hsien Chen ◽  
Chin Mou Hsu ◽  
Kuo Lin Chiu ◽  
Chu Peng Chan
Keyword(s):  
Machine Tool ◽  
High Precision ◽  
Machine Tools ◽  
High Performance ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Positional Accuracy ◽  
Precision Machine Tools ◽  
Five Axis ◽  
The Impact

Swivel spindle head is a key component used in gantry type five-axis machine tool of high performance and is of great importance in its application and design. Nowadays, more and more components are manufactured by high precision CNC machine tools, such as components of spaceflight, renewable energy and automobile, etc. Therefore, high precision machine tools of multiple axes are more and more urgently demanded, while dual axis rotary head is one of the most important components for a multi-axis machine tool. Hence, it will be a key to develop dual axis spindle head that meets high precision needs. The study explores the highly responsive direct-driving motor able to drive the spindle head to rotate with multi-driving rotary technology. The dual-driving motor rotates via multi-driving units, generates torsion that magnifies and eliminates its clearance, and then drives the spindle head to rotate. Results of the test show that the completed machine tool can meet the standards of dual axis rotary head with high precision in, no matter, speed, distance, positional accuracy, repeated accuracy or maximum torque, etc.

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.

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.

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