Geometric Error-Based Multi-Source Error Identification and Compensation Strategy for Five-Axis Side Milling

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents methods to identify the geometric errors of linear and rotation axes using the nine-line and double ball bar measurement methods, respectively. Thereafter, it introduces a method to identify the position and attitude errors of a workpiece clamped by a flat vise installed on a CNC five-axis machine tool to develop a multi-source error model and use it to compensate for geometric errors and further improve the accuracy of the CNC machine tool. The machining of the well-known "S-shaped specimen" is adopted to validate the proposed methods, and the experimental results show that the dimensional accuracy of the machined workpiece is significantly improved after compensating for geometric errors.

Several methods (and commercial solutions) exist for identifying the geometric errors of CNC five-axis machine tools and the position and attitude errors of the workpieces installed them. Although the authors show the feasibility and effectiveness of the proposed methods by machining an ”S-shaped specimen,” they are strongly encouraged to compare their machining results with those of existing identification and compensation methods (especially the commercial solutions) to further enhance the contribution of their research.

Because measurement uncertainty can significantly affect the error identification results, which can further influence the compensation and machining results, the authors are suggested to refer to the “Guide to the Expression of Uncertainty in Measurement” and perform uncertainty analyses of the proposed methods. Understanding the main factors that influence the uncertainty and identification results is important because it can help authors select suitable measurement equipment and appropriately determine the number of data points and the error calculation method to further mitigate the adverse effects of measurement uncertainty.

Finally, the content of the Conclusion section is very similar to that of the abstract; therefore, the readers may find it difficult to reflect on the main issues and topics of this paper. Therefore, the authors are suggested to rewrite the Conclusion section.

Author Response

Dear Reviewer,

Thank you very much for reviewing my manuscript and offering valuable revisions on your busy schedule. I have studied carefully and revised the manuscript immediately after receiving your comments. I will now respond to the questions you raised:

1. I added a comparison with "Holub, M.; Jankovych, R.; Vetiska.J.; Sramek, J.; Blecha, P.; Smolik, J.; Heinrich, P. Experimental Study of the Volumetric Error Effect on the Resulting Working Accuracy-Roundness. appl. Sci. 2020,10.6233." The comparison of the studies further confirms the feasibility and effectiveness of the proposed scheme;
2. I have added subsection 4.4.1, which referred to the “Guide to the Expression of Uncertainty in Measurement" and perform uncertainty analysesof the proposed methods;
3. I have rewritten the conclusion.

Thanks again for your valuable comments!

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Let me make a few comments aimed at improving and enhancing the quality of your research report.

The publication is focused on identifying and compensating for multi-source errors. By multi-source error I would imagine not only sources of geometric errors, but also sources from cutting forces, possibly from clamping, etc. It would be good to add a definition of multi-source errors. 

The calculation of geometric deviations of the linear axes of the machine is calculated based on the "9-line method" and suitably extended to identify geometric errors of the rotational axes. The resulting deviations are then related to the alignment of the workpiece in the machine workspace.

- Wouldn't it be possible to refer the corrections to the machine coordinate system and introduce them in another way than by modifying the NC code, for example to TCP in the machine coordinate system?

- On page 21, line 428-435, you write about an improvement of 32 to 43%. This can be assessed as an effective improvement. Similar results have been presented in publications on the effectiveness of corrections on test workpieces ("Holub, M.; Jankovych, R.; Vetiska, J.; Sramek, J.; Blecha, P.; Smolik, J.; Heinrich, P. Experimental Study of the Volumetric Error Effect on the Resulting Working Accuracy-Roundness. Appl. Sci. 2020, 10, 6233. https://doi.org/10.3390/app10186233" and "Usop, Z.; Sarhan, A.A.D.; Mardi, N.A.; Wahab, M.N.A. Measuring of positioning, circularity and static errors of a CNC vertical machining centre for validating the machining accuracy. Measurement 2015, 61, 39-50. https://doi.org/10.1016/j.measurement.2014.10.025"), It would be interesting to review the results of similarly focused papers and their outputs in the discussion or conclusion.

-  Lines 57-61 - force measurement from machining, prediction. There is nothing in the publication about measurement of machining forces, evaluation and prediction. It should be removed from the text or expanded in the submitted paper. I would understand this point to be a multi-source error.

- Line 405 - CMM hexagon - what is the measurement uncertainty? This would then be useful as an estimate of the uncertainty to plot in Figure 28, for all curves. The graphs would then be made larger and more readable.

-  Figure 2. - maybe better resolution of the image / text in the picture,

-  Figure 6. - bigger text font in the image,

-  Figure 13 - not relevant,

-  Figure 15 - components referenced by labels are not visible,

-  Figure 19 - not relevant,

-  Figure 16, 17, 18, 21 - very difficult to read legend,

-  Figure 23, 28 - very difficult to read axis description,

-  Table 6, 7 - missing units.

Author Response

Dear Reviewer,

Thank you very much for reviewing my manuscript and offering valuable revisions on your busy schedule. I have studied carefully and revised the manuscript immediately after receiving your comments. I will now respond to the questions you raised:

1. Your suggestions are excellent and our team will follow up with relevant research.
2. I added a comparison with "Holub, M.; Jankovych, R.; Vetiska.J.; Sramek, J.; Blecha, P.; Smolik, J.; Heinrich, P. Experimental Study of the Volumetric Error Effect on the Resulting Working Accuracy-Roundness. appl. Sci. 2020,10.6233." The comparison of the studies further confirms the feasibility and effectiveness of the proposed scheme;
3. I have removed it from the text;
4. I have added subsection 4.4.1, which referred to the “Guide to the Expression of Uncertainty in Measurement" and perform uncertainty analysesof the proposed methods;
5. Figures 2/6/15/16/17/18/21/23/28 have all been revised in accordance with the revisions made and figures 13/19 have been removed;
6. Table 6/7 units have been added.

Thanks again for your valuable comments!

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The reviewer has carefully reviewed this paper. The study presents a clear contribution to the research on geometric error identification and compensation for five-axis side milling machines. Although the conclusion section has been rewritten carefully, the authors are suggested to include the directions for future research such that readers can learn and understand the future development and application of related research.

Reviewer 2 Report

Comments and Suggestions for Authors

Proceed for publication.