An Analysis of Selected Technological Parameters’ Influences on the Tribological Properties of Products Manufactured Using the FFF Technique
Round 1
Reviewer 1 Report
Literature review and previous studies should be described in a more clearer way with grouped research for materials or measurement types, maybe in a table form. The Figure 2. should be clearer and possibly shown in schematic representation. Why the rpm and load in friction measurements was not varied? Change Figure 4. to higher resolution, in coefficient of friction (CoF) graphs add units for 'path', make clearer Figure 11. and add unit of 'weight loss'. Add comparison of CoF values for all samples in part 4 of the paper, and a minor spell check needed. Overall the paper is interesting, and after these minor ammendments is suitable for publication.
Author Response
First of all, we would like to thank you for your suggestions and comments which help us improve our manuscript.
Comment 1: Literature review and previous studies should be described in a more clearer way with grouped research for materials or measurement types, maybe in a table form.
Response 1: The literature review was added to the introduction in tabular form (Table 1) in line 131.
Comment 2: The Figure 2. should be clearer and possibly shown in schematic representation.
Response 2: Figure 2 is reworked with a schematic representation of the tribometer on which the tests were
performed
.
Comment 3: Why the rpm and load in friction measurements was not varied?
Response 3: The speed and load during the test were constant to maintain the same test conditions for all samples and orientations. By changing these parameters, it would not be possible to compare the obtained results and thus the relevance of the result would not be adequate.
Comment 4: Change Figure 4. to higher resolution.
Response 4: Figure 4 has been completely reworked with a higher resolution.
Comment 5: In coefficient of friction (CoF) graphs add units for 'path'.
Response 5: The graphical representations of Ft (N) depending on the path (s) were reworked, while the units on the individual axes have also been added.
Comment 6: Make clearer Figure 11. and add unit of 'weight loss'.
Response 6: In Figure 11, the unit was added, and weight loss values were plotted over the area of the graph columns for better clarity, and the figure was renumbered as additional figures were added.
Comment 7: Add comparison of CoF values for all samples in part 4 of the paper, and a minor spell check needed.
Response 7: We have added a table comparing the values of the input weight of the samples, the weight loss
and the percentage of material loss (Table 5).
Reviewer 2 Report
The manuscript reported a laboratory abrasive wear investigation of the samples printed of polyetherimide by the Fused Filament Fabrication. The main purpose of the research was to determine the impact of the printing strategy, i.e. the distribution of individual layers, on the amount of abrasive wear. The test was conducted on a tribometer ac-13 cording to the ASTM G65-16 standard. I consider the presented research very interesting and up-to-date. However, I have quite a lot of comments that should be considered before the article is published. Here they are
- The abstract does not contain the most important conclusions about the research, there are only generalities.
- There are many editorial errors in the article, e.g. line 74 and the abbreviations used have not been previously explained in the text.
- The plane that is subject to tribological tests should be marked in Figure 1.
- On line 133 it says that the samples are 70 x 20 x 6 mm and on line 135 it says 5 mm thick. What is the truth?
- The conditions for ultrasonic cleaning are not given. Was fluid used, if so what, were the samples dried? If so, in what way?
- Lines 169-173 are not clear “Fifteen ASTM G65 tests with Garnet Fe3Al2 (SiO4) 3 abrasive for X orientation and 15 tests for Z orientation were done to determine the arithmetic mean and the standard deviation”
- The grain size composition of the garnet abrasive is missing. The wear is dependent on the gain size of the abrasive medium.
- Formula (1) is unclear. Simplifying units, the result unit is cm3 (i.e. a unit of volume, not mass).
- I believe that the abrasive wear should be expressed as a percentage in all tests, i.e. weight loss to the initial weight of the sample. Printing in different directions and with different strategies causes both the variability of the dimensions and the mass of each of the samples.
- Figure 4 and Table 4 are very poorly constructed and do not allow the reader to easily imagine the printing strategy. Assessing the test results in this way is very difficult. The same section sizes suggest, for example, that the dimension x is equal to the dimension z.
- The coefficient of friction is always specified for a friction pair. Which is the second element of the thorn pair besides polyetherimide?
- The friction coefficient is usually 0-1. In Figures 9 and 10 it goes between 10-25. There is a bug somewhere.
- Figures 9 and 10 are very illegible. They should be developed by statistics and regression equations should be determined.
- Please enter a unit on the horizontal axis in Figures 9 and 10.
- In the line 187 is written “The extruded fiber was 0.5 mm wide” while e.g. from figures 6-10 in table 8 it is 0.25 mm. How to explain it?
- The conclusions are about this specific example of printing and the directions defined in the work. They should be general in nature, because what will happen, for example, in the case of a delta printer, or with a rotary table. I would be in favor of adopting, for example, the plane of the table, the direction of the layer increment, etc.
Considering the above, I find the article interesting, but there is still a lot of work to be done!
Author Response
First of all, we would like to thank you for your suggestions and comments which help us improve our manuscript.
Comment 1: The abstract does not contain the most important conclusions about the research, there are only generalities.
Response 1: We have supplemented the abstract with the fundamental results of research activities. The scope of the addition is given in lines (Change in lines 24-28.)
Comment 2: There are many editorial errors in the article, e.g. line 74 and the abbreviations used have not been previously explained in the text.
Response 2: We made corrections to editorial errors and supplemented the missing abbreviations of terms and mathematical quantities.
Comment 3: The plane that is subject to tribological tests should be marked in Figure 1.
Response 3: Figure 1 was supplemented with the marking of the tested surface and was generally completed to a higher resolution (Line 139 change).
Comment 4: On line 133 it says that the samples are 70 x 20 x 6 mm and on line 135 it says 5 mm thick. What is the truth?
Response 4: All samples were produced with the same thickness of 6 mm. The text on line 146 has been corrected.
Comment 5: The conditions for ultrasonic cleaning are not given. Was fluid used, if so what, were the samples dried? If so, in what way?
Response 5: Ethanol was used as the liquid in the ultrasonic cleaning of the samples, as it evaporated from the surface of the samples under normal laboratory conditions. The samples took 30 minutes to clean. The text is supplemented in lines 149-151.
Comment 6: Lines 169-173 are not clear “Fifteen ASTM G65 tests with Garnet Fe3Al2 (SiO4) 3 abrasive for X orientation and 15 tests for Z orientation were done to determine the arithmetic mean and the standard deviation
Response 6: The answer to this comment is explained in the text in lines 187-192. 6. In the experiment, we compared 10 different orientations. For each orientation, 3 pieces of samples were made and tested (15 samples in X orientation and 15 samples in Z orientation) (Figures 1, 4 and 5). An arithmetic mean was generated from the test results for each orientation (Table 6, 8). In total, 30 samples were tested. (Change in lines 186-191)
Comment 7: The grain size composition of the garnet abrasive is missing. The wear is dependent on the gain size of the abrasive medium.
Response 7: The composition of the abrasive grains was added in lines 192-195.
Comment 8: Formula (1) is unclear. Simplifying units, the result unit is cm3 (i.e. a unit of volume, not mass).
Response 8: Thanks for the inspiring comment. Given that in the experiment we considered weight losses and not volume, we considered it appropriate to remove the relationship from the contribution. The relationship was shown on line 175.
Comment 9: I believe that the abrasive wear should be expressed as a percentage in all tests, i.e. weight loss to the initial weight of the sample. Printing in different directions and with different strategies causes both the variability of the dimensions and the mass of each of the samples.
Response 9 We have added a table to the text comparing the values of the input weight of the samples, the weight loss, and the percentage loss of material, as stated in your comment (Table 5). (Line 224 change)
Comment 10: Figure 4 and Table 3 are very poorly constructed and do not allow the reader to easily imagine the printing strategy. Assessing the test results in this way is very difficult. The same section sizes suggest, for example, that the dimension x is equal to the dimension z.
Response 10: Figure 4 and Table 3 have been modified according to your requirements to clearly show how the samples were assembled. (Line 205 and 216 change)
Comment 11: The coefficient of friction is always specified for a friction pair. Which is the second element of the thorn pair besides polyetherimide?
Response 11: The second pair of friction pairs used, according to the standard, a rubberized steel disc with the specifications given in the text in lines 352-367.
Comment 12: The friction coefficient is usually 0-1. In Figures 9 and 10 it goes between 10-25. There is a bug somewhere.
Response 12: There was an error translating the article into English. The y-axis should be the friction force Ft (N). We fixed this bug by editing the graphical dependencies in the graphs on lines 352 and 367.
Comment 13: Figures 9 and 10 are very illegible. They should be developed by statistics and regression equations should be determined.
Response 13: The original numbering of Figures 9 and 10 has been changed to Figures 10 and 11 as additional figures have been added. Subsequently, regression equations were developed to determine the effect of fiber orientation on the amount of material loss during abrasive wear. Regression equations were not developed for all tested orientations since the coefficient of determination (R2) did not exceed values higher than 0.9 and therefore we do not consider it necessary to process the statistical result for the other mentioned orientations. (Line 352 and 367 change)
Comment 14: Please enter a unit on the horizontal axis in Figures 9 and 10.
Response 14: Figures 9 and 10 have been modified as necessary.
Comment 15: In the line 187 is written “The extruded fiber was 0.5 mm wide” while e.g. from figures 6-10 in table 8 it is 0.25 mm. How to explain it?
Response 15: The explanation of this phenomenon is in the text in lines 201-204. It is an elliptical shape of the fiber applied in our 3D printing.
Comment 16: The conclusions are about this specific example of printing and the directions defined in the work. They should be general in nature, because what will happen, for example, in the case of a delta printer, or with a rotary table. I would be in favor of adopting, for example, the plane of the table, the direction of the layer increment, etc.
Response 16: The prepared samples were produced in a specific way on a specific 3D printer, so it is not possible to apply the obtained results to other types of 3D printers. Although it would be possible to assume that we could expect identical test results with the same 3D printing parameters (material, temperature, layer thickness, fiber width, application strategy, direction of orientation, load, etc.).
Round 2
Reviewer 2 Report
Dear Authors!
Thank you for correcting and completing the article. I accept the article in its current form and apply for admission to print.
Good luck!
