Analysis of the Carreau Model Mixed Mechanism with a Stir Shaft in Color FDM Printing
Round 1
Reviewer 1 Report
The manuscript with the title “Analysis of Carreau model mixed mechanism with stir shaft in color FDM printing” is an interesting paper that present color mixing mechanism in an extruder. A simulation model was also created for the same purpose. However, I am concerned about the model's reliability, given that the experimental data was generated using five PLA materials with different colors, but the simulation was performed using only two different color PLA materials. Furthermore, the entire manuscript must be checked for sentence repetitions.
Aside from the major issues, the following need to be addressed:
1. The abbreviation FDM should be fully written where it appears in the manuscript for the first time.
2. The manuscript should be proofread for grammatical errors.
3. The sentences in lines 53-58 and 59-64 are the same but written differently. Both sentences should be merged and condensed. A reference should also be included where it is appropriate.
4. Line 71: The methodology should be separated from the introduction.
5. Lines 86-91 are a repeat of what was mentioned in line 71. Please check the entire manuscript for this type of error.
6. Lines 96 to 105 contain the same sentences as lines 106 to 115.
7. Line 132: What is the interpretation of the equation 1 - 3 provided? The interpretations of alphabet notation are not provided.
8. Is equation 5 supposed to be the viscosity power law model? What does the symbol H(T) in the equation mean?
9. Line 107: The section titled "Non-Newtonian Fluid Dynamic Model" is difficult to understand. Please simplify and clarify the equation descriptions.
10. Line 164: Equation 7 is not explained.
11. Look for missing space between words after a period (i.e., "."). For example, lines 50, 127, and 167.
12. Line 179: The mentioned cross-section is not depicted in Figure 6. Is the author referring to Figure 2? Furthermore, the figure description should be placed near the sentence in which it is described.
13. Line 188: The authors describe the mesh generation procedure. I'm worried about the shifting mesh region. How did the author control the moving mesh's quality? The mesh properties, such as element size, nodes, and so on, are expected to change as the mesh rotates.
14. Table 1: What are the criteria for the selection of laminar flow? Did the authors consider the material and printing process Reynold number?
15. Line 217 - 219: The author mentioned a “temporary set speed for shaft rotation at 90 RPM, which may not be reasonable speed for stirring”. Generally, a variation in the speed is expected to influence the mixing pattern of fluid, thus, it will be difficult to compare the mixing effect to experimental condition. In addition, the mixing time is another factor that needs to be considered. Therefore, this sentence may be incorrect.
16. Line 223 – 228: Because the MATLAB image processing tool was used to analyze the image in Figure 4b, the procedure for doing so should be included. Furthermore, the ANSYS software includes a function for calculating the material mixture ratio (ANSYS multiphase model). Has the author thought about this for the study? In additions only the material surface image captured from ANSYS will be analyzed by MATLAB image processing tool and this will not provide a detailed understanding of the mixing process.
Author Response
Thanks for your comments. I appreciate that the experimental data was generated using five PLA materials with different colours, but the simulation was performed using only two different colour PLA materials. The concept of simulating 2 colour PLA materials is same as for 5 colour PLA materials, where the mixing effect is mainly governed by the geometry of the rotating shaft. For the sake of computational efficient, the CFD model is developed based on 2 colour PLA materials. From the computational result, which demonstrates the effectiveness of the geometric design of the rotating shaft. This has also been practically implemented for 5 colour PLA materials.
Below is the list of how the issues being addressed:
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Comments |
Responses |
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1. The abbreviation FDM should be fully written where it appears in the manuscript for the first time. |
The abbreviation of FDM is Fused Deposition Modelling. This has been addressed in line 15 |
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2. The manuscript should be proofread for grammatical errors. |
The grammatical errors have been corrected accordingly. |
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3. The sentences in lines 53-58 and 59-64 are the same but written differently. Both sentences should be merged and condensed. A reference should also be included where it is appropriate. |
These two sections have been combined and the references updated. They are removed. |
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4. Line 71: The methodology should be separated from the introduction. |
A section of materials and methods have been added. Please refer to Line 69 to Line 84 |
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5. Lines 86-91 are a repeat of what was mentioned in line 71. Please check the entire manuscript for this type of error. |
These two parts have been combined and the more appropriate part has been retained. This has been addressed in line 85-94 |
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6. Lines 96 to 105 contain the same sentences as lines 106 to 115. |
These two parts have been combined and the more appropriate part has been retained. This has been addressed in line 97 |
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7. Line 132: What is the interpretation of the equation 1 - 3 provided? The interpretations of alphabet notation are not provided. |
Please see the original article Please refer to Line 137 to 142 |
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8. Is equation 5 supposed to be the viscosity power law model? What does the symbol H(T) in the equation mean? |
Please see the original article Please refer to Line 154-155 |
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9. Line 107: The section titled "Non-Newtonian Fluid Dynamic Model" is difficult to understand. Please simplify and clarify the equation descriptions. |
Please see the original article Please refer to Line 175 to Line 181 |
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10. Line 164: Equation 7 is not explained. |
Please see the original article Please refer to Line 191-192 |
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11. Look for missing space between words after a period (i.e., "."). For example, lines 50, 127, and 167. |
The lack of a space after the closing punctuation is added in full. |
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12. Line 179: The mentioned cross-section is not depicted in Figure 6. Is the author referring to Figure 2? Furthermore, the figure description should be placed near the sentence in which it is described. |
The reference to the section drawing should be fig 2. This has been addressed in line 199. |
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13. Line 188: The authors describe the mesh generation procedure. I'm worried about the shifting mesh region. How did the author control the moving mesh's quality? The mesh properties, such as element size, nodes, and so on, are expected to change as the mesh rotates. |
Thanks for the comment. We are dealing with the problem of incompressible flow, which indicates that the volume remains constant. Furthermore, the flow in the surrounding of rotating shaft is laminar, and we do not expect significant change on the variation of mesh. Therefore, the moving mesh quality is reliable. This has also been addressed from line 217 to line 226 |
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14. Table 1: What are the criteria for the selection of laminar flow? Did the authors consider the material and printing process Reynold number? |
The selection of flow is related to the characteristic of fluid and the printing process. Based on equation (6) Please refer Line 230 to Line 256 |
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15. Line 217 - 219: The author mentioned a “temporary set speed for shaft rotation at 90 RPM, which may not be reasonable speed for stirring”. Generally, a variation in the speed is expected to influence the mixing pattern of fluid, thus, it will be difficult to compare the mixing effect to experimental condition. In addition, the mixing time is another factor that needs to be considered. Therefore, this sentence may be incorrect. |
Thanks for pointing this error. The sentence has been rewritten from Line 269 to Line 282.
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16. Line 223 – 228: Because the MATLAB image processing tool was used to analyze the image in Figure 4b, the procedure for doing so should be included. Furthermore, the ANSYS software includes a function for calculating the material mixture ratio (ANSYS multiphase model). Has the author thought about this for the study? In additions only the material surface image captured from ANSYS will be analyzed by MATLAB image processing tool and this will not provide a detailed understanding of the mixing process. |
The procedures of using MATLAB image processing tool have been described from Line 269 to Line 282
-The 2 different colour PLA materials are homogeneous and therefore the use of ANSYS multiphase model is not feasible.
-I acknowledge that the MATLAB image processing tool does not provide a detailed understanding of the mixing process. However, the mixing process has been described.
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Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript can be improved.
Page 1. The article section “1. Non-Newtonian Fluid Dynamics Model” is repeated twice.
In Eqs. 1-5 it is necessary to decipher some symbols.
Page 5, lines 178-179. The authors cited figure 6, perhaps the authors meant figure 3.
Fig. 14, 15 and captions to them must be corrected.
Author Response
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Comments |
Responses |
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Page 1. The article section “1. Non-Newtonian Fluid Dynamics Model” is repeated twice. In Eqs. 1-5 it is necessary to decipher some symbols. |
The repetition of “Non-Newtonian Fluid Dynamics Model” has been addressed. Please see the original article |
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Page 5, lines 178-179. The authors cited figure 6, perhaps the authors meant figure 3. Fig. 14, 15 and captions to them must be corrected.
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The reference to the section drawing should be fig 2. This has been addressed in line 165. Fig. 14, 15 and captions to them had already corrected. This has been addressed in line 165 and 353-356 |
Reviewer 3 Report
1. Abstract: FDM abbreviation appears first time in the text without explanation
2. MATHEMATICAL REPRESENTATION OF MODELS 96 1. Non-Newtonian Fluid Dynamics Model – this section is duplicated in the text
3. Check the numbering and style of sections’ names. They seem to be not correct in many cases.
4. Lines 189-197 appear in italic font. Why?
5. Table 1 is very messy. Please reorganize it to make it readable.
6. Figure 4. In the Figure’s caption sections a and b are absent. Same for Fig. 5, 6, 8
7. Fig. 4 b –Necessary to give a name for the axis with the identification of units. Same for Fig. 5, 6, 8
8. Second section of a research article is usually dedicated to Materials and Methods description. The methods of the research are more or less described in this section, while the section about the material and equipment (type of polymer, coloration, type od 3D-printer, type of software used for simulation, etc.) used is fully absent.
9. Figure 13. Reference to the figure in the main text should be above the figure itself, not below.
10. Experimental section supposed to verify the correctness of the presented simulation. However, no verification is presented. The Authors are recommended to work on the comparison of simulated and experimental results, to prove that their simulation is correct.
11. Figure 12. No a and b sections are presented
12. The reference list is not representative. The authors are recommended to add more relevant researches to the reference list.
The paper is not well organized and contains a lot of mistypes and grammar mistakes. The authors are recommended to check it more carefully and correct language mistakes, mistypes, as well as formate the text in accordance with the MDPI authors guide recommendations.
Author Response
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Comments |
Responses |
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1. Abstract: FDM abbreviation appears first time in the text without explanation |
The abbreviation of FDM is Fused Deposition Modelling. This has been addressed in line 15 |
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2. MATHEMATICAL REPRESENTATION OF MODELS 96 1. Non-Newtonian Fluid Dynamics Model – this section is duplicated in the text |
These two parts have been combined and the more appropriate part has been retained. Please see the original article Please refer to Line 175 to Line 181 |
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3. Check the numbering and style of sections’ names. They seem to be not correct in many cases. |
The chapter format is updated. This has been addressed in line 33. 92. 174 etc. |
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4. Lines 189-197 appear in italic font. Why? |
The italicised section is restored. This has been addressed in line 191-192 |
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5. Table 1 is very messy. Please reorganize it to make it readable. |
Please see the original article. This has been addressed in line 231-232 |
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6. Figure 4. In the Figure’s caption sections a and b are absent. Same for Fig. 5, 6, 8 |
Please see the original article This has been addressed in line 266,303,323,356 |
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7. Fig. 4 b –Necessary to give a name for the axis with the identification of units. Same for Fig. 5, 6, 8 |
Please see the original article This has been addressed in line 266,303,323,356 |
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8. Second section of a research article is usually dedicated to Materials and Methods description. The methods of the research are more or less described in this section, while the section about the material and equipment (type of polymer, coloration, type od 3D-printer, type of software used for simulation, etc.) used is fully absent. |
Please see the original article |
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9. Figure 13. Reference to the figure in the main text should be above the figure itself, not below. |
The description in Figure 13 is updated to the top of the image. This has been addressed in line 407-417 |
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10. Experimental section supposed to verify the correctness of the presented simulation. However, no verification is presented. The Authors are recommended to work on the comparison of simulated and experimental results, to prove that their simulation is correct. |
This has been explained from line 421 to line 431 Figures with enlarge figures |
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11. Figure 12. No a and b sections are presented |
Please see the original article This has been addressed in line 400 |
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12. The reference list is not representative. The authors are recommended to add more relevant researches to the reference list. |
Please see the original article |
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The paper is not well organized and contains a lot of mistypes and grammar mistakes. The authors are recommended to check it more carefully and correct language mistakes, mistypes, as well as formate the text in accordance with the MDPI authors guide recommendations. |
Some sections have been added and correction has been made accordingly. |
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The R2 of the manuscript is suitably revised. I'd recommend accepting this manuscript. Thanks.
Reviewer 3 Report
The Authors replied to all my comments and corrected the manuscript according to the given recommendation.
