Research on Process Control of Laser-Based Direct Energy Deposition Based on Real-Time Monitoring of Molten Pool
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe submission reports experimental study on monitoring of the molten pool using CCD camera. K means clusting method is used for the segmentation of the molten pool. The proposed methodology may contribute to the advance ment in the relevant fields. For publication, following aspects need to be further discussed.
1. The proposed methodology should be verified on their efficiency via comparison with other available methods. Especially, the edge detection proposed in this study should be compared to other available methods in the literature.
2. Some terminology should be used in the consistent manner (for example width of the control mode in page 9 does not make sense)
3. It is not obvious which one is better between the constant power mode or the withdth control mode. Some more obvious proof is required.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authorsline 9: According to the ISO/ASTM 52900 standard, the laser-based process is labelled differently. --> DED-LB
line 27: According to the ISO/ASTM 52900 standard, the laser-based process is labelled differently. --> DED-LB
line 139: Please describe the resolution of the pixels. How many µm of the molten bath does a pixel represent? e.g. 1 pixel in the camera corresponds to 10 µm on the surface of the molten pool.
line 159 (formula 1): Where do the numbers come from?
line 160: In all figures are missing a scale for the geometric dimensions.
line 166: What is meant by "Z"?
line 256: The unit has no distance to the number.
line 256: How many experiments were carried out to determine the scattering?
line 264, 265: The unit has no distance to the number.
line 284: How many experiments were carried out to determine the scattering?
line 297: The unit has no distance to the number.
line 301: The scale and numbers in the Figure 11 are not recognisable. Please make it clearer.
line 304-321: Why is the text in bold?
line 322: The numbers in Figure 12 are difficult to read. Please enlarge. The scale in the Figure 12 ist not recognisable. Please make it clearer.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThis paper presents a study of the molten pool features in Laser-Directed Energy Deposition by means of image processing and feature extraction via a coaxial vision detection system. A real-time feedback control system was developed to dynamically adjust laser power for precise control of the molten pool width. Results show that increasing laser power enlarges the molten pool but may cause irregularities at high levels. The feedback system demonstrated better control and accuracy compared to a constant power mode, resulting in reduced width fluctuations and improved deposition quality.
The manuscript is well-structured and the discussion of the results is clear and reasonable, and I believe to topic is of importance for the readership of Coatings. Therefore, I recommend acceptance after minor revision.
There are a couple of comments/suggestions I would like to provide:
- The authors focus on geometrical parameters to assess the quality of the process, comparing Constant Power and Width Control modes. While this is clearly interesting, I would suggest to add a new reference value (for example the nominal height of the workpiece) to better understand how accurate the deposition process is in general terms.
- Is there any comparison regarding the final quality/performance of the products manufactured by the two modes that can be added to the discussion?
- Line 102. The acronym has already been introduced.
- Line 308. The authors state "the height at the beginning and end of the deposition layers is uneven". How large is this difference, is it possible to quantify it?
- Figure 12. There is a mismatch between the title of the y-axis and the label of the series. From the main text, I believe the y-axis should be titled "Height" and not "Width". Please correct accordingly.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe reviewer comments were addressed with relevant revisions.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
