Green Approach for Electropolishing Surface Treatments of Additive Manufactured Parts: A Comprehensive Review

Round 1

Reviewer 1 Report

Green approach for electropolishing surface treatments of additive manufactured parts: Review

 

The present review paper adds value to the scientific community, however the motivation of the present review can be further elaborated with recyclable electrolytes and therefore relevance of circular and sustainable framework, authors needs to elaborate crisply on this part. Further, I have following comments to support my recommendation on minor revision.

 

·       Title correction:

Green approach for electropolishing surface treatments of additive manufactured parts: A comprehensive review

 

·       3. Conventional Electropolishing as post-processing treatment

Additionally research work on electropolishing needs to be added, so that for the readers will have a comprehensive outlook.

Some suggestions are as follows:

o   Electropolishing and electropolishing-related allowances for IN625 alloy components fabricated by laser powder-bed fusion. Int J Adv Manuf Technol 92:4487–4499

o   Electropolishing of Inconel 718 manufactured by laser powder bed fusion: Effect of heat treatment on hardness, 3D surface topography and material ratio curve

o   Reducing surface roughness by chemical polishing of additively manufactured 3D printed 316 stainless steel components

 

·       Additionally section can be added with other means of post-processing such as shot peening and non traditional machining to emphases the advantages of electropolishing as non-contact and absence of interaction of mechanical forces.

 Some suggestions are as follows:

o   Electric discharge machining using rapid manufactured complex shape copper electrode with cryogenic cooling channel

o   Influence of post-processing techniques on the microstructure, properties and surface integrity of AlSiMg alloy processed by laser powder bed fusion technique

 

·       Characterisation and quantification of electropolished surface in terms of Surface texture evaluation suggestion are value addition for this comprehensive review

Some suggestions are as follows:

 

o   Electropolishing effect on roughness metrics of ground stainless steel: a length scale study

o   Surface Texture and Microstructural Characterization of Thin-Walled Ti6Al4V Part Processed Using Laser Powder Bed Fusion Technique: Effect of Build Direction.

o   Hybrid Surface Characterisation of Intra Thin-Walled Ti6Al4V Surfaces Produced by Laser Powder Bed Fusion Technology

 

·       Please include a future scope and challenges section highlighting the key improvements in this field such as digitisation and on-line monitoring capabilities etc.

·       Comprehensive comparison of all Ra values in a single graph would be better for readers to obtain the insight

·       Fig. 5 please double check the correctness of labeling, it appears that labels are incorrectly placed.

 

·       Please look into the typo in the entire revised draft.

Some examples are: 3.1 as to 3.4; 5.3 as to 5.1; 5.1 as to  5.2; 5.2 as to 5.3

 

 

 

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript, entitled "Green approach for electropolishing surface treatments of additive manufactured parts: Review", is a short review and concerns the treatments of metal and alloy products. At first glance, the work has the potential to be published in Metals. Unfortunately, we have to state that the manuscript is designed very carelessly and is more of an "alpha version" than a final product ready for review. Therefore, the decision is not "Reconsider after major revision" but only "Reject" for now.

 

Since the manuscript is a review, then there should be increased attention to the references of the literature. References to literature in most cases are not correctly designed, for example, the correct abbreviations of journals are not given.

Ref 30 is that a magazine, a monograph? Ref 31 – monograph? There is no DOI index by which you can figure out what it is.

Ref 22 – why capital letters?

 

References [16], [42], [62], [67]- are these conference articles (it's not clear right now)? Then they should be appropriately issued according to the MDPI rules.

Web links are generally allowed only in cases where it is absolutely impossible without them. We hope that this is the case for [3] and [44]. But both Refs don't work. In any case, as they are presented in the manuscript. Necessary the correct web addresses and arrange them according to the MDPI rules.

 

In fairness, it should be noted that the overall quality of the references is beyond doubt: there are references to both classic works and completely novel research. However, they are not enough and can be added.

 

Many of the figures are given without links and all do not contain any mention of publication permissions. We did not find a mention in the text in Fig.10. More precisely, it is on Line 457, but it is rather a reference to Fig.13. We did not find a mention in the text in Fig.19. If it is on Line 537? Then where is the link to Fig....-a?

 

A paragraph whose beginning on Line 420 does not contain a reference to the source anywhere. Is this a study by the authors? In any case, only published articles should be considered in the review. Also see on Lines 510, 515, 542.

 

Part 5, which takes up about half of the entire text, contains only 10 references. This raises questions. Actually table 5 summarizes only part 5? Or the whole review? Then why are only 8 articles considered in it.

 

The current manuscript presentation is confusing. When the manuscript is put in order, then resubmitting the manuscript for review is needed. We would be happy to review the already corrected work again.

 

The following comments will also help to prepare the manuscript for the best version:

1. This work is not the first attempt to prepare a literature review on the electropolishing in non-aqua’s electrolytes. Therefore, it is necessary to cite important and well-known reviews on the topic and note how this work differs from previous ones

1.  Deep eutectic solvents (DESs) and the metal finishing industry: where are they now? (2016)

2. Advantages of Electrochemical Polishing of Metals and Alloys in Ionic Liquids (2021)

 

2. Line 262. The term “green” authors used in this review “for the electrolytic solutions acid-free, based on the deep eutectic solvents or alcohol-based containing inorganic salts”. But Ionic Liquids (ILs) are also acid-free electrolytes and it would be desirable to justify your choice

 

3. Line 264. “The term “Deep Eutectic Solvent” (DES), as a sub-category of the ionic liquid”…

To-day, ILs and DESs from the chemical point of view are two separate groups of substances to be used in the electrochemical applications.

 

4. Line 555. Show in Fig.20 where the “cellular dendritic structures” are located.

 

5. Line 551. The caption to Fig.20 is not clear.

 

6. The review presents the classification of DESs consisting of five groups (line 277). But there is a classification consisting of 4 groups(Basics and properties of deep eutectic solvents: a review by T.Achkar et.al. 2021). It will be helpful to explain in your introductory analyzed the differences of classifications and compared the properties DES and NADES

 

We recommend that the authors, perhaps, also provide the figure(s) in Part 3 (and it contains a significant amount of information) for consideration as it is done in other parts of the manuscript.

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear Authors,

I recommend to revise the title of your work just misleads readers because it is too general. Of course, DES-based electrolytes are widely used for electropolishing of metals and alloys but they are well known to be far not the only “green solvents”. Many reviews are already published on using the other types of not less “green solvents” and even more effective than DESs.

Author Response

Reviewer comments:

I recommend to revise the title of your work just misleads readers because it is too general. Of course, DES-based electrolytes are widely used for electropolishing of metals and alloys but they are well known to be far not the only “green solvents”. Many reviews are already published on using the other types of not less “green solvents” and even more effective than DESs.

Reply: Probably there are some greener products than DESs, but we have decided to dedicate this review to them.

Round 2

Reviewer 2 Report

The authors may have mistakenly concluded that the comments were of a formal nature. The review was formally changed only in accordance with the comments made, but the title remained the same. The presentation is still not entirely satisfactory. For example, the text does not clearly distinguish between its unpublished and cited results (Fig.5,6). There is no uniformity in the designation of natural DES. Fig.11 shows a graph of current vs. time, and in the caption "Potential-current density curve". It is not clear how the result E=25V was obtained from such a graph. The authors should read their review more carefully.

 

Author Response

Dear Editor,

authors appreciated the comments of the reviewer. Revising the paper according to the reviewer’s recommendation has significantly increased the quality of the paper and made it more comprehensive and readable.

The list of the suggested changes and comments are reported below. Amendments are reported in red in the text.

Your sincerely,

Annalisa Acquesta

 

The authors may have mistakenly concluded that the comments were of a formal nature. The review was formally changed only in accordance with the comments made, but the title remained the same. The presentation is still not entirely satisfactory.

The authors, aware that they cannot include all possible types of existing green treatments, maintain that the term green is, in any case, suitable for this review, as also approved by other reviewers.

For example, the text does not clearly distinguish between its unpublished and cited results (Fig.5,6).

Figure 5 belongs to the authors. The reference of figure 6 has been added.

 

 There is no uniformity in the designation of natural DES.

The definition of natural DES is given in Lines 333-335

 

Fig.11 shows a graph of current vs. time, and in the caption "Potential-current density curve". It is not clear how the result E=25V was obtained from such a graph. The authors should read their review more carefully.

 

The caption is right. The x-axis designation on the figure was wrong. The reason for choosing to apply 25 V has been explained.

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

If Figure 5 is the work of the authors of the manuscript and :
1. it is not a generalizing scheme or diagram,
2. is its own experimental result,
3. it has not been published anywhere before (it is impossible to give references to it),
 then it should be removed from the manuscript (because the manuscript is a review-article).
In addition, the figure (if it is an experimental result) there is no dimension scale.

 

Author Response

Dear reviewer,

authors appreciated the comments of the reviewer.  

The figure 5 has been published in our previous paper, albeit in a different guise. The scale is now reported in it.

We have modified the paper’s text accordingly and added the right reference. All changes are reported in red.

Your sincerely,

Tullio Monetta

 

 

If Figure 5 is the work of the authors of the manuscript and :

1. it is not a generalizing scheme or diagram,
2. is its own experimental result,
3. it has not been published anywhere before (it is impossible to give references to it),

 then it should be removed from the manuscript (because the manuscript is a review-article).

In addition, the figure (if it is an experimental result) there is no dimension scale.