Monitoring of Joint Gap Formation in Laser Beam Butt Welding using Neural Network-Based Acoustic Emission Analysis

Round 1

Reviewer 1 Report

This manuscript present the analysis of sound signal acquired from butt-joined laser welding process. The framework in this analysis provides the alternative for an online monitoring system to detect the existence of gap which was significant to predict the strength of welded joint. 

  The work presented in this manuscript was well arranged. However, there are several comments that the authors might need to give attention to improve the clarity of the presentation of the author's work in this manuscript   In this manuscript the use of term "gap formation" were found to be quite frequent including the title. In the context of the sentence where these terms was used, the meaning of the "gap formation" was quite misleading. The sentences was like telling the reader that the gap was formed as a results from welding process.Basically, the formation of gap was not happen during the welding process but it is formed as a result from improper prior preparation of the workpiece. The work demonstrated in this manuscript also lead to the understanding that the gap was formed during the specimen preparation.Thus, the clarity of the sentences might need improvement.If there is the case that the gap naturally formed during the welding process, the authors need to provide the evident.   In Table 1, the authors explained the distance of where two different types of microphones were located from the weld point. Authors might need to clarify critically the decision of choosing these distance as it might affect the sound reflection, attenuation etc which might influenced the overall results of this study   Line 194:Authors explained that the threshold for the gap tolerance was 0.06mm. The details on how this threshold value was established might need to be explained as it was quite large (60% in case of the 0.1mm gap).Authors might also need to explained on how to control these tolerance during the specimen preparation in section 2.1 as this tolerance seems to be critically affect the results in Fig 8(b) and Fig9(b)   Line 261 to 265: The details on the considered frequency range for the spectogram magnitude calculation is needed. This is due to the fact that not all the frequency component clearly giving the information related to the existence of gap. Based on Fig 5, some of the freqency band was badly affected by the noise especially below 10kHz (less discrepancies of color tone between no-gap and with-gap region). This might also be the main factor of the reduction of classification efficiency in Fig 8(b) and Fig 9(b) Apart from frequency range, the selection of FFT size, window size and overlapping size might also need the detail explanation as it could affect the resolution of STFT, especially when we are dealing with the wide band signal   Overall, the manuscript was good. The significant of research was clearly stated. The problem statement and objective was aligned and well concluded from the discussed results

English writing was fine. 

Author Response

Dear Reviewer,
I would like to express my sincere gratitude for your valuable insights and thoughtful comments on our manuscript. Your feedback has been instrumental in improving the quality and rigor of our work. We have carefully considered each of your suggestions and have made the necessary revisions to address the concerns raised. The manuscript has been updated, and you can identify the revised content by the blue. Please find attached our detailed responses to your comments. We eagerly await your reevaluation of the revised manuscript and hope that our efforts reflect the commitment to excellence that your review has inspired. Thank you once again for your time and expertise.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

I would like to express my sincere gratitude for your valuable insights and thoughtful comments on our manuscript. Your feedback has been instrumental in improving the quality and rigor of our work. We have carefully considered each of your suggestions and have made the necessary revisions to address the concerns raised. The manuscript has been updated, and you can identify the revised content by the blue. Please find attached our detailed responses to your comments. We eagerly await your reevaluation of the revised manuscript and hope that our efforts reflect the commitment to excellence that your review has inspired. Thank you once again for your time and expertise.

Author Response File: Author Response.pdf

Reviewer 3 Report

- The authors should present the most important results of this research in a quantitative form in the abstract.

- The introduction is poorly written, and it is necessary to increase the number of references, and the type of writing of the introduction should also be such that it leads the reader's mind to the innovation of the main article of this article.

- The main innovation of this article should also be mentioned at the end of the introduction section.

- The explanations provided about the equipment and experimental tests are good, but the authors should definitely add pictures of the laser welded parts in the article.

- The results presented are weak and need to be strengthened. For example, in section 3-1-1, the authors need to provide more commentary on the effect of process parameters on keyhole size and present the relationship between keyhole size and process parameters quantitatively and using mechanical and metallurgical results.

- In my opinion, the presented results need a lot of fundamental changes and improvements. It is recommended that the authors use the mechanical and metallurgical results to interpret and strengthen the results.

-My advice to the authors is to make fundamental corrections and resubmit the article.

 

Author Response

Dear Reviewer,

I would like to express my sincere gratitude for your valuable insights and thoughtful comments on our manuscript. Your feedback has been instrumental in improving the quality and rigor of our work. We have carefully considered each of your suggestions and have made the necessary revisions to address the concerns raised. The manuscript has been updated, and you can identify the revised content by the blue. Please find attached our detailed responses to your comments. We eagerly await your reevaluation of the revised manuscript and hope that our efforts reflect the commitment to excellence that your review has inspired. Thank you once again for your time and expertise.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Since the revised paper has been improved, I have no further inquiries and recommend acceptance.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript can be accepted in the present form.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf