Machining Performance for Ultrasonic-Assisted Magnetic Abrasive Finishing of a Titanium Alloy: A Comparison with Magnetic Abrasive Finishing

Round 1

Reviewer 1 Report

The current paper pertains to an interesting topic with a practical value as well. Namely, a study concerning the machining performance for Ultrasonic Assisted Magnetic Abrasive Finishing of titanium Alloy is presented. In general, it is very well written, with an adequate theoretical background, while, the experimental methods and the obtained results and conclusions are also well presented and discussed. I feel that only some minor comments have to be made.

More specifically:

·         please keep all the roughness values in consistent units in μm (see line 48). Moreover, please separate the roughness value from the roughness index Ra.

·         In sake of completeness please include the mechanical properties of the TC4 titanium alloy.

·         please explain how the machining parameters of Table 1 were emerged. Are the optimal or based on other criteria?

·         it would be useful a summarized table of the different tested machining conditions to be quoted (amplitude, machining gap, etc.).

·         some more details regarding the surface measuring methods are necessary. Is any ISO was followed and what was the measuring parameters (cut-off length, number of measurements etc.). Please provide some more details. Moreover, some microscope images of the surface would be also very interesting and enlightening.

·         are the cutting forces remain constant through the whole process? As the roughness gradually change through time are the cutting forces remain the same? I think it would be interesting the possible change of the cutting forces in respect of the machining time to be also studied.

 Considering the aforementioned, in my humble opinion, the current paper can be accepted after a major revision.

Author Response

Response to Reviewer 1 Comments

Thank you very much for your valuable comments. According to the comments, the modifications of this paper are as follows:

Point 1: Please keep all the roughness values in consistent units in μm (see line 48). Moreover, please separate the roughness value from the roughness index Ra.

Response 1: Similar issues were uniformly revised, including other parts of the paper.

Point 2: In sake of completeness please include the mechanical properties of the TC4 titanium alloy.

Response 2: The mechanical properties of the TC4 is supplemented in Table 1, and the original Table 1 is changed to Table 2

Point 3: Please explain how the machining parameters of Table 1 were emerged. Are the optimal or based on other criteria?

Response 3: The machining parameters in the original Table 1 are excellent in MAF, so this group of parameters is selected for comparison with UAMAF in this paper, in order to show the machining performance of UAMAF. The relevant description is shown in the last part of the first paragraph in section 3.

Point 4: It would be useful a summarized table of the different tested machining conditions to be quoted (amplitude, machining gap, etc.).

Response 4: The detailed machining parameters are listed in Table2, and the corresponding description was also modified in the paper.

Point 5: Some more details regarding the surface measuring methods are necessary. Is any ISO was followed and what was the measuring parameters (cut-off length, number of measurements etc.). Please provide some more details. Moreover, some microscope images of the surface would be also very interesting and enlightening.

Response 5: The measuring methods of cutting force, surface roughness, and surface topography of magnetic abrasive and surface micrograph were added in the last paragraph of section 3.

The surface micrographs after milling, MAF, and UAMAF were listed in Figure 12 of section 4.2.

Point 6: Are the cutting forces remain constant through the whole process? As the roughness gradually change through time are the cutting forces remain the same? I think it would be interesting the possible change of the cutting forces in respect of the machining time to be also studied.

Response 6: Because of the short machining time in this study, the cutting force is almost unchanged, but with the extension of the machining time, the cutting force will have a relatively large change with the machining time. It is a good idea to study the change of cutting force with machining time. The relevant research results will be presented in another paper devoted to the effect of initial surface topography on cutting force and torque.

Thank you again for your valuable suggestions and time for this paper.

Reviewer 2 Report

1.      Section 4.1: In Figure 6, a sudden drop in cutting force is observed at a certain time (around 12 sec). Please justify and incorporate the reason in manuscript.

2.      Introduction section should have sufficient recent literature.

3.      In Table 1, values of different machining parameters are presented. What are the reasons behind selection of such particular values?

4.      Line 181, “The ultrasonic amplitude A is 0, 6, 8, 10, 12, and 14μm, respectively, ……” Please justify the reason behind this selection. DO same for section 4.1.2, 4.1.3, 4.1.4.

5.      In page 6 there is section 4.1.1, but in page 7, section is named as 3.1.2. Please check the whole manuscript.

6.      In Figure 11, Surface roughness value rapidly decreased within 0-10 min, while almost no change is observed for 15-40 min. Why so? (For UAMAF)

7.      Please provide SEM & EDS micrograph of after machined surface and justify proper reason behind machining characteristics.

Author Response

Response to Reviewer 2 Comments

Thank you very much for your valuable comments. According to the comments, the modifications of this paper are as follows:

Point 1: Section 4.1: In Figure 6, a sudden drop in cutting force is observed at a certain time (around 12 sec). Please justify and incorporate the reason in manuscript.

Response 1: “It can be seen from Figure 6 that there is a sudden drop of cutting force from the machining period of UAMAF to that of MAF. Equation (12) shows that the cutting force in UAMAF consists of ultrasonic force and magnetic force. The sudden drop is due to the disappearance of ultrasonic force in the machining period of MAF.” This part is shown in the last part of the first paragraph in section 4.1.

Point 2: Introduction section should have sufficient recent literature.

Response 2: More recent references were added to the introduction, and the research status was reorganized.

Point 3: In Table 1, values of different machining parameters are presented. What are the reasons behind selection of such particular values?

Response 3: All machining parameters were suggested to be summarized into a table by another reviewer. So Table 1 shows all the parameters now. The machining parameters in the original Table 1 are excellent in MAF, so this group of parameters is selected for comparison with UAMAF in this paper, in order to show the machining performance of UAMAF. The relevant description is shown in the last part of the first paragraph in section 3.

Point 4: Line 181, “The ultrasonic amplitude A is 0, 6, 8, 10, 12, and 14μm, respectively, ……” Please justify the reason behind this selection. DO same for section 4.1.2, 4.1.3, 4.1.4.

Response 4: The selection of machining parameters is based on the parameter range of the previous researches such as References 7 and 8 in this paper, combined with the performance of the experiment setup and the preliminary exploratory experiment. The relevant description is shown in the first paragraph of section 3.

Point 5: In page 6 there is section 4.1.1, but in page 7, section is named as 3.1.2. Please check the whole manuscript.

Response 5: This section has been revised and the whole manuscript has been carefully checked.

Point 6: In Figure 11, Surface roughness value rapidly decreased within 0-10 min, while almost no change is observed for 15-40 min. Why so? (For UAMAF)

Response 6: There are many crests and troughs on the workpiece surface after milling. Due to the vertex effect, and the combined effect of ultrasonic force and magnetic force in UAMAF, the crests are quickly removed. So, surface roughness value rapidly decreases within 0-10 min. With the removed of the troughs, surface roughness value decreases more slowly, until unchanged basically. Meanwhile, it is indicated that the limit capacity of surface roughness that can be processed by this group of machining parameters has been approached after UAMAF for 15 minutes. The relevant description is shown in the second and the third paragraphs of section 4.2.

Point 7: Please provide SEM & EDS micrograph of after machined surface and justify proper reason behind machining characteristics.

Response 7: The surface micrographs after milling, MAF, and UAMAF are listed in Figure 12 of section 4.2. The surface micrographs are used to analyze the surface roughness and surface characteristics in this section.

Thank you again for your valuable suggestions and time for this paper.

Round 2

Reviewer 1 Report

Authors have significantly improve their manuscript according to the reviewers' comments, thus, in my opinion, it can be accepted.

Reviewer 2 Report

Can be accepted in this form.