Integration of Lattice Structures into the Boring Bars as a Passive Chatter Suppression Technique: Concepualization, Modelling and Simulation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. What is the unique contribution of this work compared to the following studies?

• Development of an anti-vibration cutting tool combining lattice structures infill with damping particles, Mechanical Systems and Signal Processing 228 (2025) 112425.
• A new cutting tool filled with metallic lattice and design method for vibration suppression in milling, Mechanical Systems and Signal Processing 212 (2024) 111310.

2. What is the relationship between subsection 2.2 and the subsections focused on simulation? The simulations are based on solid element theory, whereas subsection 2.2 employs beam theory.
3. Are the volumes of the ellipsoidal and cylindrical hollows in the simulations identical? The authors should address how variations in hollow volumes affect the natural frequency and dynamic displacement. Which one is better?
4. Why were six different lattice structures only filled into the ellipsoidal hollow rather than the cylindrical hollow?
5. Section 2.8 kept the beam diameters and lattice unit heights constant, resulting in different relative densities and masses. However, the natural frequencies and amplitudes of the FRF for tools corresponding to Models 1 through 6 are similar. How should the optimal lattice type be selected in this scenario?
6. Experiments on the cutting tool integrating lattice structures should be conducted to validate the findings.
7. The manuscript’s organization needs refinement. For example, the parametric modeling section should precede the simulation analysis.
8. The discussion section should analyze the research results, interpret data, and compare findings with existing literature. It should not be combined with the conclusion.
9. Both the discussion and conclusion sections contain lengthy paragraphs. These should be made more concise and focused on the key findings
10. The quality of all figures is suboptimal and needs improvement to enhance clarity and readability.
11. The unit of the cutting speed should be explicitly stated.
12. There are formatting inconsistencies throughout the manuscript. For instance, a single parenthesis appears on page 10.
13. Figure 5 lacks clarity in its presentation. The first and second steps seem to use the same equation, which requires clarification.
14. The flowchart in Figure 6 lacks logical coherence and detailed explanation. It should clearly illustrate the experimental validation of the simulation results.
15. The specific parameter settings used for the harmonic response analysis in Chapter 2 should be explicitly stated.

Comments on the Quality of English Language

1. The manuscript requires thorough proofreading, as there are numerous spelling errors, such as "forinstantaneous" on page 3 and "wich" on page 4.

Author Response

1. What is the unique contribution of this work compared to the following studies?

• Development of an anti-vibration cutting tool combining lattice structures infill with damping particles, Mechanical Systems and Signal Processing228 (2025) 112425.
• A new cutting tool filled with metallic lattice and design method for vibration suppression in milling, Mechanical Systems and Signal Processing212 (2024) 111310.

Answer:

We appreciate the reviewer’s valuable comment. The unique contributions of our work compared to the mentioned studies are as follows:

• Different Target and Approach:
  Unlike the cited studies that focus on general milling tool holders or combine structure structures with damping particles, our study specifically targets boring bars with internal structure integration without any additional damping materials.
• Optimization of Internal Hollow Geometry:
  We introduced a methodology to determine and optimize the largest possible ellipsoidal hollow inside the boring bar while maintaining mechanical integrity, which directly impacts the dynamic behavior positively — a novel approach compared to previous studies.
• Development of a Dedicated CAD Simulation Tool:
  We developed a parametric and automated CAD simulation tool that enables flexible and scalable modeling of various structure structures. This tool greatly accelerates the modeling process and minimizes human errors, overcoming major limitations of commercial CAD software.
• Comprehensive Structure Design Evaluation:
  We systematically evaluated six different 3D structure structures and analyzed the effects of design parameters (such as beam diameter) on vibration suppression, providing a more extensive and detailed study compared to previous works.
• Significant Improvement in Vibration Damping:
  A vibration amplitude reduction of up to 69.81% was achieved compared to the original boring bar, demonstrating the effectiveness of the proposed design approach.

2. What is the relationship between subsection 2.2 and the subsections focused on simulation? The simulations are based on solid element theory, whereas subsection 2.2 employs beam theory.

Answer:

We thank the reviewer for the insightful comment. Considering the reviewers' opinions, it was deemed more appropriate to remove this section.

3. Are the volumes of the ellipsoidal and cylindrical hollows in the simulations identical? The authors should address how variations in hollow volumes affect the natural frequency and dynamic displacement. Which one is better?

Answer:

We appreciate the reviewer’s important observation. In our study, both the ellipsoidal and cylindrical hollows were designed with the same maximum diameter (18 mm) and the same hollow length (130 mm) to ensure comparable boundary conditions. Due to its geometric properties, the ellipsoidal cavity proves to be more advantageous. The volume affects dynamic performance:

As seen from the results, the ellipsoidal hollow leads to a higher natural frequency and a lower dynamic displacement amplitude compared to the cylindrical hollow.
This improvement can be attributed to the better distribution of mass and inertia characteristics in the ellipsoidal geometry, which enhances dynamic stiffness while maintaining strength. Therefore, the ellipsoidal hollow was selected as the preferred design for the subsequent integration of structure structures.

4. Why were six different structure structures only filled into the ellipsoidal hollow rather than the cylindrical hollow?

Answer:

We thank the reviewer for the valuable question. Following the preliminary analysis, it was found that the ellipsoidal hollow provided superior dynamic performance compared to the cylindrical hollow, with a higher natural frequency and lower vibration amplitude. Therefore, to ensure a consistent and optimized baseline for evaluating different structure structures, only the ellipsoidal hollow configuration was selected for further analysis. Focusing on the ellipsoidal hollow allowed us to clearly observe and compare the effects of different structure designs under the best-performing hollow geometry.

5. Section 2.8 kept the beam diameters and structure unit heights constant, resulting in different relative densities and masses. However, the natural frequencies and amplitudes of the FRF for tools corresponding to Models 1 through 6 are similar. How should the optimal structure type be selected in this scenario?

Answer:

We thank the reviewer for raising this important point. It is correct that keeping the beam diameters and structure unit heights constant led to differences in relative densities and masses among Models 1 to 6, yet their natural frequencies remained relatively similar. In this study, the primary selection criterion for the optimal structure type was minimizing the dynamic displacement amplitude (i.e., improving vibration suppression), rather than solely relying on natural frequency shifts.
Among the analyzed models, Model 3 demonstrated the lowest FRF amplitude, achieving the greatest reduction in vibration compared to the others.
Moreover, considering the goal of maintaining a lightweight structure without excessive mass increase, Model 3 offered a favorable balance between vibration damping and relative density. Thus, the optimal structure type was selected based on its dynamic performance (lowest amplitude) and reasonable mass efficiency.

6. Experiments on the cutting tool integrating structure structures should be conducted to validate the findings.

Answer:

We thank the reviewer for this valuable suggestion. As stated in the manuscript, this scientific study was primarily focused on the conceptual development, simulation modeling, and numerical evaluation of structure-integrated boring bars.
The simulation models were validated through modal testing of the original (non-structure) boring bar to ensure the reliability of the numerical approach.
The physical manufacturing and cutting experiments with structure-integrated tools are building upon the modeling framework and simulation findings established in this study.

7. The manuscript’s organization needs refinement. For example, the parametric modeling section should precede the simulation analysis.

Answer:

We thank the reviewer for this helpful recommendation. The current organization of the manuscript was structured to first demonstrate the necessity and motivation for developing a parametric CAD modeling tool, based on the challenges encountered during the simulation analyses. Thus, the simulation studies were presented first to highlight the complexity and time-consuming nature of manual structure modeling. The parametric modeling section was then introduced as a solution to these challenges. The section on parametric modeling was subsequently introduced as a solution to these challenges. For these reasons, we request that the manuscript be retained in this format with the reviewer's consent.

8. The discussion section should analyze the research results, interpret data, and compare findings with existing literature. It should not be combined with the conclusion.

Answer:

We appreciate the reviewer’s valuable observation. In our manuscript, the Discussion has already been presented separately in Section 4, where the research findings were analyzed and interpreted. We acknowledge the importance of ensuring a clear distinction between the Discussion and the Conclusion. Therefore, in line with the reviewer's suggestion, we have reorganized the conclusion section into bullet points. We have also moved Figure 32 and its comment to the Discussion section.

9. Both the discussion and conclusion sections contain lengthy paragraphs. These should be made more concise and focused on the key findings.

Answer:

We thank the referee for his valuable suggestion. Accordingly, we have revised these sections by shortening long paragraphs, removing redundant information, and emphasizing only key findings and interpretations to improve the clarity and readability of the article.

10. The quality of all figures is suboptimal and needs improvement to enhance clarity and readability.

Answer:

We thank the reviewer for his valuable comments. Accordingly, we have reviewed all the figures and made some corrections, improving resolution, increasing font sizes where necessary, and adjusting color contrasts to further improve clarity and meet the journal's standards.

11. The unit of the cutting speed should be explicitly stated.

Answer:

Cutting speed was given in the section 2.1 as V_c = 75 m/min

12. There are formatting inconsistencies throughout the manuscript. For instance, a single parenthesis appears on page 10.

Answer:

We appreciate the careful observations of the reviewers. We have carefully checked the manuscript for formatting inconsistencies such as mismatched brackets and other typographical problems. We have corrected any inconsistencies to ensure a professional presentation.

13. Figure 5 lacks clarity in its presentation. The first and second steps seem to use the same equation, which requires clarification.

Answer:

We thank the reviewer for the valuable observation. In Figure 5, aforementioned steps indeed involve similar bending stress equations, but they are applied to different models: the first step refers to the original boring bar (reference model), while the second step applies the theoretical approach to the simulated model Similarly, third and fourth steps use this control mechanism for modified boring bar with cylindrical hollow. To avoid confusion, we revised the explanation in the figure caption and the related text.

14. The flowchart in Figure 6 lacks logical coherence and detailed explanation. It should clearly illustrate the experimental validation of the simulation results.

Answer:

We thank the reviewer for the helpful comment. Accordingly, we revised the flowchart to better distinguish between simulation steps and experimental validation steps and provided a more detailed explanation in both the figure and the accompanying text to ensure logical coherence and clarity.

15. The specific parameter settings used for the harmonic response analysis in Chapter 2 should be explicitly stated.

Answer:

We thank the reviewer for his insightful comment. To address this, we have explicitly stated the specific parameter settings used in the Harmonic Response Analysis (HRA) in Chapter 2.

Comments on the Quality of English Language

16. The manuscript requires thorough proofreading, as there are numerous spelling errors, such as "forinstantaneous" on page 3 and "wich" on page 4.

Answer:

The manuscript was processed with a thorough proofreading.

Reviewer 2 Report

Comments and Suggestions for Authors

Overall, a good work has been done. Scientific and fundamental contributions are much low, though.

Many sections are too long. Could be condensed. Contents of section 2.2 are well known and textbook stuff; section 2.9 is way too long and not required. Section 4 can be condensed a lot.

Few figures seem to have been taken from other references and given without no citations.

Remove the wording "..in this chapter..". This is not a thesis.

Few equations need proper editing. Ex. Eq. 5.

Text needs careful editing. Ex. Spelling of Timoshenko in line 224; title of section 2.7.;  

Author Response

1. Overall, a good work has been done. Scientific and fundamental contributions are much low, though.

Answer:

We sincerely thank the reviewer for the encouraging overall evaluation. The current work focuses on methodological development and practical implementation, it lays an important scientific foundation for future research by providing a validated modeling framework and a flexible parametric tool for structure integration.

2. Many sections are too long. Could be condensed. Contents of section 2.2 are well known and textbook stuff; section 2.9 is way too long and not required. Section 4 can be condensed a lot.

Answer:

Based on the valuable opinions of the editors, Section 2.2 has been deleted. Other sections have been revised.

3. Few figures seem to have been taken from other references and given without no citations.

Answer:

The necessary references were added into the manuscript.

4. Remove the wording "..in this chapter..". This is not a thesis.

Answer:

The necessary corrections have been made.

5. Few equations need proper editing. Ex. Eq. 5.

Answer:

The equations in the manuscript were reviewed in line with the valuable opinions of the editors.

6. Text needs careful editing. Ex. Spelling of Timoshenko in line 224; title of section 2.7.;  

 Answer:

The necessary corrections have been made

Reviewer 3 Report

Comments and Suggestions for Authors

This paper investigates the passive damping technology in which vibration damping is realised by integrating lattice structures into the boring bar. The research involves several stages. Firstly, the largest possible hollow space in the boring bar was determined and the two main influencing factors of stiffness and natural frequency were harmonised. Based on the validated simulation model, an FEM analysis of vibration reduction was carried out using six different lattice structures. Based on the FEA results, an application-specific parameterised CAD simulation tool was developed with suitable approaches in order to circumvent the limitations of conventional CAD software. For the hollow integrated into the boring bar, the ellipsoid shapes proved to be more suitable than the cylinder due to their superior dynamic performance. The first lattice structure: cube lattice with side cross supports improved the damping by 55.58% compared to the reference model. Next, five more modelling steps were performed with the best result reducing vibrations by 67.79%. Additionally, the adjustments on the beam diameter of the lattice units resulted better dynamic performance which corresponds to a vibration suppression of 69.81%. At the end, the parametric CAD software tool (add-in) was developed in SolidWorks environment using its Application Programming Interface (API). This tool allows automation of the process of generating lattices structures with the possibility of selecting one of five base cell types.

The paper is interesting, but needs minor improvements.

Comments:

1. line 18: is "strucutres", should be "structures".
2. line 21: is "shaps", should be "shapes".
3. line 186, table 2, first column: is "Chemi-", should be "Chemical".
4. line 186, table caption: add material name "51CrV4".
5. Figure 4: which graph is "real" and which is "imaginary" part? Mark these as c) and d)
6. line 337, Figure 7 caption: "moment of inertias (A-A and B-B)" is correct formulation? I propose a change: "cross-sections  (A-A and B-B) and and the corresponding moment of inertia's areas". How were these areas achieved?
7. line 397, Figure 10 caption: add a), b), c), d) marks and descriptions. Zoom d) chart:  experimental and simulation results.
8. line 339: is "The HRA was performed in the same way with the two modified boring bars, i.e. C18H3 and E18H3 (Figure 11)." But in Figure 11 caption are only results for "E18H3" model. Improve it.
9. line 415: add abbreviation "CLWSCS" after "Cube lattice with side cross support".
10. Figure 15: where are C18H3 and E18H3 results? Improve it.
11. Figure 17 caption: add description of a) and b)
12. Figure 17 a): where is results of "Simulation - model 1"? I can't see it on the graph.
13. Figure 18: add "d=1mm" for first description.

Comments on the Quality of English Language

The paper should be carefully reviewed for language. There are sometimes typos e.g:

1. line 18: is "strucutres", should be "structures".
2. line 21: is "shaps", should be "shapes".

Author Response

This paper investigates the passive damping technology in which vibration damping is realised by integrating structure structures into the boring bar. The research involves several stages. Firstly, the largest possible hollow space in the boring bar was determined and the two main influencing factors of stiffness and natural frequency were harmonised. Based on the validated simulation model, an FEM analysis of vibration reduction was carried out using six different structure structures. Based on the FEA results, an application-specific parameterised CAD simulation tool was developed with suitable approaches in order to circumvent the limitations of conventional CAD software. For the hollow integrated into the boring bar, the ellipsoid shapes proved to be more suitable than the cylinder due to their superior dynamic performance. The first structure structure: cube structure with side cross supports improved the damping by 55.58% compared to the reference model. Next, five more modelling steps were performed with the best result reducing vibrations by 67.79%. Additionally, the adjustments on the beam diameter of the structure units resulted better dynamic performance which corresponds to a vibration suppression of 69.81%. At the end, the parametric CAD software tool (add-in) was developed in SolidWorks environment using its Application Programming Interface (API). This tool allows automation of the process of generating structures structures with the possibility of selecting one of five base cell types.

The paper is interesting, but needs minor improvements.

Comments:

1. line 18: is "strucutres", should be "structures".

Answer:

The necessary corrections have been made.

2. line 21: is "shaps", should be "shapes".

Answer:

The necessary corrections have been made.

3. line 186, table 2, first column: is "Chemi-", should be "Chemical".

Answer:

The necessary corrections have been made.

4. line 186, table caption: add material name "51CrV4".

Answer:

The necessary corrections have been made.

5. Figure 4: which graph is "real" and which is "imaginary" part? Mark these as c) and d)

Answer:

The necessary corrections have been made.

6. line 337, Figure 7 caption: "moment of inertias (A-A and B-B)" is correct formulation? I propose a change: "cross-sections  (A-A and B-B) and and the corresponding moment of inertia's areas". How were these areas achieved?

Answer:

The necessary corrections have been made.

7. line 397, Figure 10 caption: add a), b), c), d) marks and descriptions. Zoom d) chart:  experimental and simulation results.

Answer:

The necessary corrections have been made.

8. line 339: is "The HRA was performed in the same way with the two modified boring bars, i.e. C18H3 and E18H3 (Figure 11)." But in Figure 11 caption are only results for "E18H3" model. Improve it.

Answer:

The text has been edited to eliminate confusion.

9. line 415: add abbreviation "CLWSCS" after "Cube structure with side cross support".

Answer:

The necessary corrections have been made.

10. Figure 15: where are C18H3 and E18H3 results? Improve it.

Answer:

The graph incorporates the relevant curves for C18H3 (Cylindrical hollow) and E18H3 (Ellipsoidal hollow). For the simplicity, values for the E18H3 design, which has better performance than the C18H3, are presented.

11. Figure 17 caption: add description of a) and b)

Answer:

The necessary corrections have been made.

12. Figure 17 a): where is results of "Simulation - model 1"? I can't see it on the graph.

Answer:

The Model 1 corresponds to the CLWSCS design. As the results of this design are presented in detail in Figure 15, they have not been included in Figure 17 to facilitate a more straightforward visual representation.

13. Figure 18: add "d=1mm" for first description.

Answer:

The necessary corrections have been made.

Comments on the Quality of English Language

The paper should be carefully reviewed for language. There are sometimes typos e.g:

Answer:

The necessary corrections have been made.

1. line 18: is "strucutres", should be "structures".

Answer:

The necessary corrections have been made.

2. line 21: is "shaps", should be "shapes".

Answer:

The necessary corrections have been made.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

In their response, the authors outlined their contributions compared to existing studies. However, it is important to note that previous research has also addressed the use of lattice structures to fill cylindrical and ellipsoidal hollows for suppressing vibrations in cutting tools. These studies investigate the influence of design parameters on vibration suppression performance, which means that some of the claimed contributions may not be unique to this work.

The authors should specify the unique aspects of boring bars when designing the internal structure, in contrast to general milling tools and tool holders in the existing works. To provide readers with a comprehensive understanding of the state of the art, they should cite the following most relevant works in the introduction section and carefully compare their findings with these existing studies to clarify their true contributions:

• Development of an anti-vibration cutting tool combining lattice structures infill with damping particles, Mechanical Systems and Signal Processing 228 (2025) 112425.
• A new cutting tool filled with metallic lattice and design method for vibration suppression in milling, Mechanical Systems and Signal Processing 212 (2024) 111310.
• Vibration Suppression in Turning TiAl6V4 Using Additively Manufactured Tool Holders with Specially Structured, Particle Filled Hollow Elements, Procedia Manufacturing, 40 (2019) 32-37.

Author Response

We appreciate the reviewer’s valuable comment. The three studies under consideration have been incorporated into the relevant section of our article. Subsequently, the aspects not encompassed by these articles and addressed in our study have been clarified. Moreover, the parametric modelling tool is not a subject of the studies under consideration; it is a secondary output of the present article. It is already explained in section 3.

Reviewer 2 Report

Comments and Suggestions for Authors

The revisions done are still not up to a level that addresses the top major comment and deficiency of the work: scientific soundness and academic rigor. 

Author Response

All key results have been re-evaluated in line with the reviewer’s earlier feedback to ensure consistency, clarity, and depth in interpretation.

We have also carefully revised the entire manuscript for language quality and technical accuracy, with final proofreading performed by a native English-speaking academic editor.

Furthermore, all modifications have been highlighted in the revised manuscript to ensure transparency. If there are still specific aspects that the reviewer feels remain insufficient, we would greatly appreciate further clarification so we can address them in a more targeted manner.

We thank the reviewer for their continued feedback and commitment to improving the quality of our work.

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed my concerns and comments. I would like to recommend the acceptance of this paper.

Reviewer 2 Report

Comments and Suggestions for Authors

Revisions and response are acceptable.