The Standardization of Machining Test Methods for Multi-axis Machine Tools by Using Compound Test Pieces

2021 ◽  
Vol 11 (4) ◽  
pp. 35-42
Author(s):  
Joo Hyun Kim
Keyword(s):  
Machine Tools ◽  
Test Methods ◽  
Test Pieces ◽  
Machining Test ◽  
Compound Test

scholarly journals Influence of Tool Length and Profile Errors on the Inaccuracy of Cubic-Machining Test Results

2021 ◽  
Vol 5 (2) ◽  
pp. 51
Author(s):  
Zongze Li ◽  
Hiroki Ogata ◽  
Ryuta Sato ◽  
Keiichi Shirase ◽  
Shigehiko Sakamoto
Keyword(s):  
Machine Tools ◽  
Test Accuracy ◽  
Test Results ◽  
Machining Error ◽  
Tool Profile ◽  
Machining Test ◽  
The Difference ◽  
Side Error ◽  
Profile Errors ◽  
Five Axis

A cubic-machining test has been proposed to evaluate the geometric errors of rotary axes in five-axis machine tools using a 3 × 3 zone area in the same plane with different tool postures. However, as only the height deviation among the machining zones is detected by evaluating the test results, the machining test results are expected to be affected by some error parameters of tool sides, such as tool length and profile errors, and there is no research investigation on how the tool side error influences the cubic-machining test accuracy. In this study, machining inaccuracies caused by tool length and tool profile errors were investigated. The machining error caused by tool length error was formulated, and an intentional tool length error was introduced in the simulations and actual machining tests. As a result, the formulated and simulated influence of tool length error agreed with the actual machining results. Moreover, it was confirmed that the difference between the simulation result and the actual machining result can be explained by the influence of the tool profile error. This indicates that the accuracy of the cubic-machining test is directly affected by tool side errors.

A novel method for evaluating the validity of dynamic accuracy test pieces for five-axis machine tools

2020 ◽  
Vol 234 (11) ◽  
pp. 2189-2210 ◽  
Author(s):  
Weiwei He ◽  
Liping Wang ◽  
Liwen Guan
Keyword(s):  
Test Piece ◽  
Machine Tools ◽  
Dynamic Error ◽  
System Model ◽  
Feed System ◽  
Mathematical Relationship ◽  
Dynamic Accuracy ◽  
Accuracy Test ◽  
Test Pieces ◽  
Five Axis

The detection method for direct machining the standard test pieces, which is commonly employed to exhibit the machining precision of five-axis machine tools, can truly reflect the dynamic accuracy of five-axis machine tools in the actual machining process. Existing theories on explaining the phenomenon that the ability of S-shaped test pieces to detect dynamic accuracy for five-axis machine tools are stronger than those of NAS979 test pieces mostly used the qualitative research methods, and they cannot be quantitatively used to reveal the mathematical relationship between machine tools and test pieces. Therefore, this article makes the first attempt to investigate the quantitative evaluation method for the validity of dynamic accuracy test pieces. The dynamic error function of the servo feed system in the frequency domain was derived first by establishing the mechanical system model and control system model. The method of dipole cancellation was used to acquire a simplified transfer function for the dynamic error affected by the input. Based on the zero-order hold property of the discrete input signals, the expression of dynamic error affected by input in the time domain, which intuitively shows the mathematical relationship among the machine tool performances, the test piece characteristics and the dynamic error of the servo feed system, was obtained. Then, the novel evaluation methods of the linear combinatorial value and the combinatorial linear combinatorial value were proposed. A series of comparative analyses between an S-shaped test piece and an NAS979 test piece were carried out based on the proposed new evaluation methods. A machining experiment conducted on a five-axis machine tool is used to verify the evaluation results.

Accuracy design of high precision machine tools using error sensitivity analysis methodology

2016 ◽  
Vol 231 (18) ◽  
pp. 3401-3413 ◽  
Author(s):  
Wenjie Tian ◽  
Shaopeng Liu ◽  
Xingxing Liu
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tool ◽  
Machine Tools ◽  
Geometric Error ◽  
Sensitivity Index ◽  
Assembly Accuracy ◽  
Machining Test ◽  
Precision Machine Tools ◽  
Design And Manufacture ◽  
Source Errors

Geometric accuracy is a crucially important performance factor for machine tools. Theoretically, the effects of source errors on pose accuracy (positional and angular accuracy) of 3-, 4- or 5-axis machine tools cannot fully be compensated by software, and only those pose errors associated with the permission motions are compensatable by means of error compensation. Therefore, the uncompensatable pose errors should be strictly guaranteed in the processes of design and manufacture. In this paper, after the geometric error model is established, the source errors affecting the uncompensatable pose accuracy are identified out of all the source errors. In order to enhance the understanding of which source errors have more influences on the pose accuracy, a probabilistic sensitivity analysis method is proposed, and the global sensitivity index is defined to evaluate the influence in the overall workspace. According to the sensitivity analysis results, the uncompensatable pose accuracy index is allocated to each source error. And then, assembly accuracy acceptance criteria are proposed as a guideline for machine assemblers. As an application example, the presented approaches are applied to the accuracy design and manufacture of a 4-axis machine tool, and double ball bar measurement and machining test are carried out to check the accuracy of the designed machine tool.

scholarly journals Machining Tests to Evaluate Machine Tool Thermal Displacement in Z-Direction: Proposal to ISO 10791-10

2020 ◽  
Vol 14 (3) ◽  
pp. 380-385
Author(s):  
Soichi Ibaraki ◽  
◽  
Rin Okumura
Keyword(s):  
Machine Tool ◽  
Standardized Tests ◽  
Machine Tools ◽  
Thermal Deformation ◽  
Axial Direction ◽  
Technical Committee ◽  
Test Procedures ◽  
Thermal Displacement ◽  
Machining Test ◽  
Thermal Influence

Thermal deformation is one of the contributors of critical errors of machine tools. ISO 10791-10 describes standardized tests to evaluate a machine tool’s thermal deformation; however, they do not include cutting operations. By repeatedly performing the same machining feature, one can observe the change in geometric accuracy, which is typically caused by the thermal influence of the environment or the heat generated by the machine tool. This paper proposes a simple machining test to evaluate a machine tool’s thermal displacement in the tool’s axial direction (Z-direction). Together with a technical committee of the Japan Machine Tool Builders’ Association, the authors proposed the revision of ISO 10791-10 in ISO/TC39/SC2 to add the present machining tests. This paper presents the test procedures and case studies as well as a comparison with an alternative machining test.

A novel approach to calculating the dynamic error reflected on an S-shaped test piece

2020 ◽  
pp. 095440622096215
Author(s):  
Weiwei He ◽  
Liping Wang ◽  
Liwen Guan
Keyword(s):  
Test Piece ◽  
Machine Tools ◽  
Dynamic Error ◽  
Dynamic Performance ◽  
Error Distribution ◽  
Feed System ◽  
Test Pieces ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Five Axis

This paper proposes a novel approach to calculating the dynamic error distribution reflected on an S-shaped test piece. First, a numerical model of an S-shaped test piece is established, and the distribution characteristics for the twist angle and curvature are analysed. Second, a delay continuous method (DCM), which can transform the discrete input into a delayed step input, is presented to express the single-axis dynamic error affected by the input quantitatively in the form of a mathematical expression. Based on the sinusoidal input, the feasibility of the DCM is verified by comparing the experimental results of a Simulink simulation model and a mathematical expression derived by the DCM. Third, according to a new three-point tangential (NTPT) positioning algorithm and the DCM, this article makes the first attempt to investigate the quantitative calculation method of the influence of the dynamic performance of a servo feed system for five-axis numerical control (NC) machine tools on the dynamic error distribution for S-shaped test pieces after processing. Parameter p, representing the dynamic characteristic of the servo feed system, is varied to compare the difference of the dynamic error distribution law on S-shaped test pieces. The calculation results show that the parameter p can be adjusted to reduce the dynamic error of the final machined test pieces. It is important to improve the dynamic performance of servo feed systems for five-axis NC machine tools and enhance the machining quality of test pieces. In addition, compared with the calculation results of the dynamic error distribution for an NAS979 test piece, the S-shaped test piece can reflect the dynamic performance of the servo feed system for five-axis NC machine tools more accurately and effectively. Finally, the effectiveness of the proposed calculation method is verified through processing experiments on a five-axis NC machine tool.

scholarly journals Comparative analyses of water soaking and thickness swelling of particleboard versus different test methods

2008 ◽  
pp. 65-74
Author(s):  
Milanka Djiporovic-Momcilovic ◽  
Mladjan Popovic ◽  
Ivana Gavrilovic-Grmusa ◽  
Jovan Miljkovic
Keyword(s):  
Test Methods ◽  
National Standard ◽  
Thickness Swelling ◽  
European Standard ◽  
Test Pieces ◽  
Hygroscopic Properties ◽  
Significant Difference ◽  
High Level ◽  
Panel Thickness

In regard to its hygroscopic properties, particleboard is dimensionally unstable material when exposed to water or in the atmosphere of high level of humidity. Since today several different standardized methods for determination of thickness swelling exist, the aim of this study was focused on comparison of different testing methods. In this aim, three different methods for determination of water soaking and thickness swelling were compared, two of which were defined by national standard SRPS D.C8.104 and one was defined by European standard EN 317. The results of testing of both properties have shown no significant difference between the EN method based on 50?50 mm test pieces and the SRPS method based on test pieces of 100?100 mm format, suggesting that these two methods can be used alternatively. On the other hand, the results obtained by the SRPS method utilizing the 25?25 mm test pieces, differed significantly from both previous methods. The results were lower for both water soaking and thickness swelling regardless of panel thickness.

A pyramid-shaped machining test to identify rotary axis error motions on five-axis machine tools: software development and a case study

2017 ◽  
Vol 94 (1-4) ◽  
pp. 227-237 ◽  
Author(s):  
Soichi Ibaraki ◽  
Shota Tsujimoto ◽  
Yu Nagai ◽  
Yasutaka Sakai ◽  
Shigeki Morimoto ◽  
...  
Keyword(s):  
Software Development ◽  
Machine Tools ◽  
Rotary Axis ◽  
Machining Test ◽  
Five Axis
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