The Influence of the Coating on the Saw Blade on the Energy Intensity of Cross-Cutting of Wood
Round 1
Reviewer 1 Report
Interesting paper on the cutting of wood. It feels more like a Undergraduate or Msc project for industry than a scientific study. It mainly covers what happened but lacks the context of other work or the conclusions as to why the results are as they are.
It would be good to show close up images of the teeth. I cannot really tell much from the zoomed-out images.
Why were the cutting parameters chosen?
A Main Effects Plot could be used for the results. This would help with the visualisation of the results which was not the best. i.e. plots on a graph without trends identified.
The power was quite specific in terms of 2decimal places. Was there a range of power, etc.
Interesting study however could be taken further to look at the influence of the reducing friction of the cutting tool and wear on the process. The reduction in power due to certain aspects is not explained in enough detail. Was it due to the coating, the tool geometry, or the wear aspects of the tool? I think this is needed for the scientific nature of the paper.
Conclusions did not contain specific reference to the numbers and critical review.
Author Response
Thank you for reviewing the article. The authors have carefully corrected the article according to the reviewer's instructions.
Author Response File: 
Author Response.docx
Reviewer 2 Report
In the abstract authors state that the aim of their study is to determine the
effect of selected coatings on the energy demand of saw blades. The energy required for sawing was quantified by cutting power. Further, authors state that the purpose of their experiments was "to confirm or refute their validity in the process of transverse sawing of wood", but they don't clearly state what is there hypothesis to be tested by experiment and data analysis.
Usually, coatings are used to extend tool life, minimize friction etc. and their
their suitability for a specific purpose can't determined based on required cutting power. Usually tool life measurements are used for that purpose.
In the introduction authors give general remarks about coatings and there intended use in machining and state that hardness of coating and friction between saw tooth and machined material (wood) are the most important parameters. In materials and methods section authors present only hardness (HV) values for each coating and results from tribological test to quantify the friction coefficient between coating material and workpiece material is not provided.
In the introduction authors didn't present any data or theory on how different
variables, that they used in their experiments, affect cutting power, so results of their measurements could be compared to what is already known.
This is important because in the results section authors present some results that are opposite to what is expected. They present results that in the same cutting conditions in some circumstances, sawing of spruce wood requires more power that beech wood.
According to literature for the same cutting conditions cutting power required
in sawing beech wood should be 30% to 50% more than what is required in sawing spruce wood. Authors don't even explain why this may be so in their experiment.
Also, they get the result that cutting power drops in value as feed speed is
increased from 6 m/min to 12 m/min while other variables are kept constant. From the theory and experiments it is well known fact that if no other parameter changes, average power required for cutting rises proportionally with raise in feed speed. Authors also didn't explain why is this happening in their experiment.
In the materials and methods section authors don't present any detailed data about coated samples which could help in analysis of measurement data.
Authors didn't provide any data on how many repetitions of cutting power measurements they made for each combination of input variables. If they made only one measurement for every combination of variables, results of their statistical analysis are questionable.
From presented results and statistical analysis, stated research hypothesis is not tested and due to before mentioned differences between obtained results and previous knowledge it is my opinion that research hypothesis can't be tested without more measurement data.
Results are presented in unclear way and conclusions are not clearly presented.
Conclusions are not consistent and clearly presented and are not supported by
data and analysis that is presented.
Due to flaws that are detected it is my opinion that authors would need to carry out further experiments and provide more data to test their research hypothesis.
More detailed comments are presented below.
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Title -> energy intensity how is it defined and how did you measure that quantity
Cutting in transverse direction -> usually the term cross-cutting is used
(you also use it in keywords)
How is article by authors Barcik et al. (2009) relevant to your research? It deals
with milling of poplar and you state in accordance with literature that "the hardness of the material and the friction between the blade and workpiece are the most important parameters with respect to the particular saw blade tooth geometry".
"Recent work focusing on cutting mechanics (Atkins a. G. 2009; Orlowski K. et al.2013; Kopecký, Z., Rousek, M.2007) found that the crack resistance of a workpiece (fracture toughness) is of equal importance to force and friction when determining the force and reducing the action of forces." - It is not clear from the text how is this related to your research? Does coatings that you tested impact crack formation or fracture toughness?
"The aim of the experiment was to determine the effect of the saw blade coating on the energy consumption and parameters of the cross-section of wood." - What do you mean by parameters of the cross-section of wood? From the results section it can be seen that you only analyzed power, e.g. required energy for cutting.
"In practice, this means finding out the values of the torque on the crankshaft of the experimental device with respect to the course of the frequency of revolutions under certain conditions and finally evaluating the results."- Power required for cutting can be measured in other ways, for example by measuring force and rotational frequency or by measuring electrical power.
cutting-edge angle -> Did you mean rake angle?
Can you please clarify what do you mean by term SK blade? Did you mean the saw blade with tungsten carbide teeth? I was trying to figure out the difference from presented figures.
In the introduction you state that friction between tool tip and workpiece is one
of the two most important parameters. In materials and methods section you provide only hardness. Tribological tests are basic tests in testing differences between different types of coatings. Please provide the data for coefficient of friction between coating material and workpiece material that you used in the experiment and details of wear of coating material and workpiece from tribological tests.
What was the thickness of coatings?
One of the parameters that also has influence on power required for sawing is radius of tool tip. Coatings influence the tool tip radius. Please provide the data of measured tool tip radius with coatings.
"Effect and torque transmission on the circular saw blade is transmitted
by means of the cutting part (cutting mechanism)" - What did you mean by this sentence?
Figure 4 -> Caption is not informative enough.
There is no need to explain gravimetry. It is a standard method and only reference to ISO standard is enough.
Figure 5. Time should be in seconds, not in s^-1
Calculated values of required power are presented to 2 decimal places. Can you give some evidence that only the last number is uncertain. Usually uncertainty associated with power measurements is much higher.
From the text it can be concluded that in Table 4. and 5. you present the lowest
values of cutting power while machining beech and spruce wood in different cutting conditions. Why did you present this results in such a way? How does it help in testing your research hypothesis.
What does power in Figure 6. represent? Is it the average of all of the measurements (with different cutting speeds and different feeed speeds and different workpiece materials) for given coating material? If it is than that is wrong, because it can't be compared that way.
How do you explain that cutting power drops in value as feed speed is increased from 6 m/min to 12 m/min? This is opposite to what is expected. Cutting power should increase as feed speed is increased if all other influencing factors are kept constant.
In Figure 8. you present the results of measured cutting power as a function of cutting speed. At which feed speed were this values measured? Are this some average values for different cutting speeds? On which workpiece material were this values obtained?
In Figure 9. you get the result that cutting power required for sawing spruce wood is higher that for beech wood, it is especially evident for SK saw. This is strange because in the same cutting conditions spruce wood requires less power to cut. How do you explain this?
In the results section of the article you state:"The objective of the experiment was to evaluate the associated factors during the process of transverse wood cutting" and in abstract you state: "The aim of the study is to determine the effect of coatings on the energy demand of saw blades". This is not the same thing.
In the results you claim: "Further on, the use of coats appropriate for saw blade coatings improves their efficiency, prolongs the durability, and so decreases the wear, what should increase the cutting quality and decrease their energy intensity."- How is this visible from your results? Did you measure tool life? Did you measure tool wear?
How did you prove this claim with your measurement results and analysis? "Here, we show that plating circular saw blades with certain metals can help
to reduce the electrical charging of wood dust during cutting, which has significant implications for occupational safety, healthcare, and lifetime of filter systems"
In the conclusion you state some general remarks, but what are conclusions that can be drawn from your research that you presented in this article? At the start of the article you state your research hypothesis. What are the conclusions based on that hypothesis and your research data and analysis.
Author Response
Thanks for reviewing the article. The authors carefully corrected the article according to the reviewer's instructions.
As a reminder of the graphical results of statistics: Figure 6 represents a one-factor analysis of the variance of the average values for a given coating, which, according to the statistical evaluation of the level of significance, has an impact on the final performance value, that is why we present this graph.
Other comments are revised in the article.
Author Response File: Author Response.docx
Reviewer 3 Report
In this paper the authors applied different coatings , such as AlTiN, AlTiCrN and AlTiCrSiN on the saw blades with different types. The authors performed their experiments on two different wood's material. The aim was to evaluate the effect of coating saw blades on the energy consumption, parameters of the cross-section of wood, cutting parameters (feed speed, cutting speed) and their interaction. They concluded the Coating AlTiN has a positive n the energy intensity of the wood cutting process and reduces the size of the cutting power.
I think the paper is well-thought out and the results can be helpful specially when we are dealing with hardwood's cutting. However, I have have some comments on this paper:
1. Please include the obtained results in the Abstract.
2. The problem statement is not clearly discussed in the Introduction.
3. Please, describe the novelty of your work.
4. Nothing is mentioned about the coating process and its influence on the cutting process. Please add some more papers about it and explain about your applied coatings and please state the advantages of your applied coating regarding other ones used in other different papers (i.e. compare your coatings with other ones).
5. I think the main problem in the Introduction section is that, the authors should add more paper related to the title.
6. Please describe more about the Table 6 in detail. According to this table which parameters do have the most influence on the cutting process.
7. In the Results and Discussion section, the author mainly described about their obtained results. The authors should compare their results with the results of other works performed in this area.
8. Please provide (include) the main obtained results in Conclusions.
9. I think most used references are old, the authors should use and include references that have been done at least in last 5 years.
Therefore, in my opinion the papers can be published after major revision.
Author Response
Thanks for reviewing the article. The authors carefully corrected the article according to the reviewer's instructions.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
1. Abstract has been improved with results.
2. Views of the saws do not provide much information other than a saw. Better to show the individual teeth.
3. Average power has been given but then a range could be given as well.
4. Results still just a series of points without trendlines, etc.
5. Very limited scientific aspects.
6. Would be better in third person.
Author Response
The images presented in the article show used saw blades in research with the same tooth geometry. We re-evaluated the measured results in the STATISTICA program and included the new graphs in the article. We have added additional knowledge to the conclusion.
Author Response File: Author Response.docx
Reviewer 2 Report
One of the main objections to the article was disagreement between the results of cutting power that authors presented and previous research and well known facts how cutting power changes with feed speed and in cutting softwoods (spruce) and hardwoods (beech). Authors get the opposite results of what is expected and their explanation is not backed by solid facts. Their explanation is based on assumptions ("The critical decrease in performance in some cases, in which it should be higher, is caused by random influences, such as the natural frequency of the saw blade, inhomogeneous material, changes in wood moisture. At a low frequency of rotation of the saw blade, caused by the performance characteristic of the electric motor, the speed of the chip removed during the sawing process is also reduced. At the moment of cutting off the chip, the potential energy changes into the energy of elastic deformation, and then it changes into the kinetic energy of the movement of the chip."). If their goal was to investigate the influence of the selected coatings on energy consumption while cross-cutting wood with circular saws, then the experiment should have been designed in such a way to give clear answer to that question. From obtained results and given explanation there is no clear answer to that question.
I still think that article, especially the experimental part, has some serious flaws and that additional experiments are required in order to get reliable results and conclusions considering the aim of the work stated by the authors.
Author Response
The measured results, the number of which we recalculated according to the size of the basic statistical file (we added to the article, the methodology section), were again subjected to evaluation in the STATISTICA program and more suitable graphs were chosen to display the results.
Author Response File: Author Response.docx
Reviewer 3 Report
The authors answered to the all question clearly.
So, in my opinion the paper can be published as it is.
Author Response
We thank the reviewer for his comments on the article.
Round 3
Reviewer 2 Report
No comments.
