Development of a Method and a Smart System for Tool Critical Life Real-Time Monitoring
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors,
the manuscript is interesting but requires improvement. Please follow the comments.
1. A literature review limited to 9 publications is insufficient. The topics discussed by the authors are widely described in the literature, therefore this part of the manuscript should be expanded.
2. Line 31 - The current trend is towards Industry 5.0. Please explain why you focus on the previous version of Industry 4.0.
3. The introduction should provide a wider range of examples of instruments for assessing tool wear. Please cite: https://doi.org/10.1016/j.jasrep.2024.104637
The authors used the GelSight device for topographic measurements of microworn surfaces. This instrument uses a gel-backed elastomer tactile membrane, which provides different approach from traditionally used optical microscopes and sensors, signal analysis to investigate tool wear.
4. Chapter 2.1 - should be in the introduction section. Generally, theory is not permited to be in methodology section.
5. Fig. 9 - please provide trend line with coefficient of determination.
6. Fig. 14 - there is light reflection and picture is difficult to see. Please could you provide microscopic view, or SEM?
Author Response
Responses to the reviewer 1’s comments
Thanks for the comments. The responses to each comment are addressed as follows.
- A literature review limited to 9 publications is insufficient. The topics discussed by the authors are widely described in the literature, therefore this part of the manuscript should be expanded.
Response:
Four more literature reviews (shown below) have been added into the Introduction Section of the manuscript.
a. Endika Tapia, Unai Lopez-Novoa, Leonardo Sastoque-Pinilla, Luis Norberto López-de-Lacalle , “Implementation of a scalable platform for real-time monitoring of machine tools”, Computers in Industry, Vol. 155, 104065 (https://doi.org/10.1016/j.compind.2023.104065).
b. Iñigo Aldekoa, Ander del Olmo, Leonardo Sastoque-Pinilla, Sara Sendino-Mouliet, Unai Lopez-Novoa, Luis Norberto López de Lacalle , “Early detection of tool wear in electromechanical broaching machines by monitoring main stroke servomotors”, “Mechanical Systems and Signal Processing”, Mechanical Systems and Signal Processing, Volume 204, p. 110773, 2023 (https://doi.org/10.1016/j.ymssp.2023.110773).
c. Endika Tapia, Leonardo Sastoque-Pinilla, Unai Lopez-Novoa, Iñigo Bediaga, and Norberto López de Lacalle, “Assessing Industrial Communication Protocols to Bridge the Gap between Machine Tools and Software Monitoring”, Sensors 2023, 23(12), p. 5694, (https://doi.org/10.3390/s23125694).
d. Katarzyna Peta, Katarzyna Peta , W. James Stemp, Richard Chen, George Love, Christopher A. Brown, “Multiscale characterizations of topographic measurements on lithic materials and microwear using a GelSight Max: Investigating potential archaeological applications”, Journal of Archaeological Science: Reports, Volume 57, p. 104637, 2024 (https://doi.org/10.1016/j.jasrep.2024.104637)
- Line 31 - The current trend is towards Industry 5.0. Please explain why you focus on the previous version of Industry 4.0.
Response:
Further, the current trend is towards Industry 5.0. It recognizes the power of industry to achieve societal goals beyond jobs and growth, to become a resilient provider of prosperity for a sustainable, human-centric and resilient European industry. This study started several years ago and will keep following the paradigm and vision of Industry 4.0 and 5.0.
Explanation mentioned above has been added into the Introduction Section.
- The introduction should provide a wider range of examples of instruments for assessing tool wear. Please cite: https://doi.org/10.1016/j.jasrep.2024.104637
The authors used the GelSight device for topographic measurements of microworn surfaces. This instrument uses a gel-backed elastomer tactile membrane, which provides different approach from traditionally used optical microscopes and sensors, signal analysis to investigate tool wear.
Response:
Per the recommendation of the reviewer, the paper intitled “Multiscale characterizations of topographic measurements on lithic materials and microwear using a GelSight Max: Investigating potential archaeological applications” (Katarzyna Peta et.at, Journal of Archaeological Science: Reports, Volume 57, September 2024,) has been cited in the manuscript as reference [11].
4. Chapter 2.1 - should be in the introduction section. Generally, theory is not permitted to be in methodology section.
Response:
Chapter 2.1 has been moved to the Introduction section.
5. 9 - please provide trend line with coefficient of determination.
Response:
Per the comment of the reviewer, the trend line has been added into Fig. 9.
6. 14 - there is light reflection and picture is difficult to see. Please could you provide microscopic view, or SEM?
Response:
Fig. 14 has been replaced by other figure for better quality.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article presents the development of an intelligent system for real-time monitoring of tool wear and machining quality by analyzing spindle load current variations. The following factors need to be addressed for publication:
(1) There are other methods to monitor the processing status, such as force measurement, acoustic emission detection, etc. Please compare them in the introduction section, pointing out the strengths and weaknesses of the methods used in the manuscript.
(2) Experimental findings suggest that a current sampling frequency of 1 Hz. Is it related to the cutting parameters? For transient cutting processes, is 1Hz able to demonstrate the transient tool state.
(3) The experiments primarily involved continuous straight-line cutting. Whether the current fluctuates when the tool cuts in and out.
(4) The main factor affecting the current is the cutting force, and the influencing parameters include parameters such as feed rate and depth of cut, which should be included in the model.
(5) The main cutting parameter that affects the surface roughness is the feed, in addition the surface roughness is the result to be concerned with the finishing process, which does not allow the tool to experience severe wear, so it is recommended to consider the range of applicability of the model.
(6) Figure 8, Figure 10 has an irregularly drawn flowchart.
(7) Figure 14 lacks scale.
Author Response
Responses to the reviewer 2’s comments
Thanks for the comments. The responses to each comment are addressed as follows.
1. There are other methods to monitor the processing status, such as force measurement, acoustic emission detection, etc. Please compare them in the introduction section, pointing out the strengths and weaknesses of the methods used in the manuscript.
Response:
Several methods can be used for machine status/machining process monitoring, such as force measurement, acoustic emission detection, and vibration detection etc. A dynamometer can be used for force measurement, but due to its expensive cost, inconvenient installation, and limited machine space for its installment, it is not suitable for the applications requiring 24-hours monitoring for many machines in a factory or the machining process with a large workpiece. Much research explored the possibility of using sound/voice signals to diagnose machine health status or abnormalities of manufacturing process. However, the interferences problem caused by the background noise from other machines/environment is till the major issue needed to be resolved for on-line precision diagnosis. The vibration signals can precisely reflect the instant status of a tool, a machine, or a manufacturing process through time domain/or frequency domain signal analysis with the advantages of lower cost and relatively easy setup. The motor current of a machine spindle of a CNC machine could provide same the functions with even lower cost comparing to the vibration signals, and a digital current meter can be easily installed in the electrical cabinet of a CNC machine to collect the spindle load current. Therefore, the motor current has become a popular signal for real-time monitoring functions.
2. Experimental findings suggest that a current sampling frequency of 1 Hz. Is it related to the cutting parameters? For transient cutting processes, is 1Hz able to demonstrate the transient tool state.
Response:
Due to the limit of sampling rate, the fastest current sampling frequency of 1 Hz was used in the study. Because tool wear is continuously accumulating during the machining process (slow wear rate at the early and middle stage, and fast wear rate at the final stage), the cutting vibration and spindle motor load current vary following a certain trend as mentioned in the manuscript. 1 Hz sampling rate is quick enough to collect sufficient data to show the signal variation trend to differentiate the tool wear status. In this study, the relatively current increase ratio was calculated based on the sampled current data and compared with the threshold value, and the verification experimental results showed its feasibility.
3. The experiments primarily involved continuous straight-line cutting. Whether the current fluctuates when the tool cuts in and out.
Response:
The current fluctuates when the tool cuts in and out. Because those current signals collected at the cut-in and cut-out area cannot reflect the true tool wear status, they should be ignored for the signal feature calculation. For this consideration, the human-computer interface (HCI) system was designed to help users to choose the locations of cutting path where to start and end collecting current data from the NC program.
4. The main factor affecting the current is the cutting force, and the influencing parameters include parameters such as feed rate and depth of cut, which should be included in the model.
Response:
Different machining parameters, such as feed rate, spindle speed, depth of cut etc., will cause different chip load and cutting forces. The model built in the study were developed based on different experiments with different machining parameters, and the tool wear diagnosis rules was developed based on the result of whether the relative current increasing ratio is close to /or exceed the threshold value. Because the relative current increasing ratio is defined as the ratio between the instant current and the current of the first cut of a new cutter, the increasing ratio could reflect the instant status of the accumulated tool wear.
5. The main cutting parameter that affects the surface roughness is the feed, in addition the surface roughness is the result to be concerned with the finishing process, which does not allow the tool to experience severe wear, so it is recommended to consider the range of applicability of the model.
Response:
For finishing process, surface roughness is usually a machining tolerance needs to be followed. Thus, the tool wear should be controlled by the requirement of surface roughness instead the standard of ISO 8668-2. It is why the correlation model between tool wear and surface roughness was developed in this study. The correlation model could provide two functions: (1) predict the surface roughness based on the relative ratio of current increase; (2) define the threshold value based on the tolerable surface roughness defined. With the second function, a user can define a threshold value based on the correlation model. When the current increasing ratio is close to /or exceed the threshold value, the system will display alarm to remind that the cutter has worn and will cause unqualified surface roughness.
Explanation mentioned above has been added to the revised manuscript.
6. Figure 8, Figure 10 has an irregularly drawn flowchart.
Response:
The flowchart shown in Figure 8 and Figure 10 have been revised for better quality and understanding.
7. Figure 14 lacks scale.
Response:
Scale has been added into Fig. 14.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have made changes according to my suggestions. Thus, I recommend for acceptance in its current form.
Author Response
Round 2 - Responses to the reviewer 2’s comments
Thanks for the comments. The responses to each comment are addressed as follows.
- Comment 1:
Thank you for your pointing out. I/we agree with this comment. Therefore, I /we have….[Explain what change you have made. Mention exactly where in the revised manuscript this change can be found-page number, paragraph, and line] ”[ updated text in the manuscript if necessary]”.
Response:
The response comments shown below can be found at lines 127~142 in the page 3 of the manuscript.
“Several methods can be used for machine status/machining process monitoring, such as force measurement, acoustic emission detection, and vibration detection etc. A dynamometer can be used for force measurement, but due to its expensive cost, inconvenient installation, and limited machine space for its installment, it is not suitable for the applications requiring 24-hours monitoring for many machines in a factory or the machining process with a large workpiece. Much research explored the possibility of using sound/voice signals to diagnose machine health status or abnormalities of manufacturing process. However, the interferences problem caused by the background noise from other machines/environment is till the major issue needed to be resolved for on-line precision diagnosis. The vibration signals can precisely reflect the instant status of a tool, a machine, or a manufacturing process through time domain/or frequency domain signal analysis with the advantages of lower cost and relatively easy setup. The motor current of a machine spindle of a CNC machine could provide same the functions with even lower cost comparing to the vibration signals, and a digital current meter can be easily installed in the electrical cabinet of a CNC machine to collect the spindle load current. Therefore, the motor current has become a popular signal for real-time monitoring functions.”
- Comment 2:
Experimental findings suggest that a current sampling frequency of 1 Hz. Is it related to the cutting parameters? For transient cutting processes, is 1Hz able to demonstrate the transient tool state.
Response:
The response comments shown below can be found at lines 187~193 in the pages 4~ 5 of the manuscript.
“The fastest current sampling frequency-1 Hz of the digital current meter was used in the study. Because tool wear is continuously accumulating during the machining process (slow wear rate at the early and middle stage, and fast wear rate at the final stage), the cutting vibration and spindle motor load current vary following a certain trend. 1 Hz sampling rate is quick enough to collect sufficient data to show the signal variation trend to differentiate the varying tool wear status. In this study, the relatively current increase ratio was calculated based on the sampled current data and compared with the threshold value”.
Author Response File: Author Response.pdf
