Round 1

Reviewer 1 Report

The content of the article is interesting and concerns the modeling of a hand prosthesis with seven degrees of freedom and prototyping with the use of 3D printing. The method of modeling and simulating elements based on FEM and with the use of topological optimization was also presented. The parameters of additive manufacturing using the Ultimaker device were described.

The title of the article does not correspond to its content, a more appropriate title should refer to the modeling and simulation process of a hand prosthesis intended for production with incremental methods.

In the article, the analysis of manufacturing costs is performed in a general manner, hence it should not be included in the title.

The quality of the drawings is average and poor in several places due to their size.

The literature is modest and insufficient and needs to be expanded.

Author Response

REPLAY TO REVIEWER 1

 

Ref. No.: Applsci-1525756

Title: Low-cost manufacturing of an upper limb prosthesis with 7 degrees of freedom

Journal: Applied Sciences

Answer date: February 2^nd, 2022

Corresponding author: Torres San Miguel C.R.

Email: ctorress@ipn.mx

 

We thank the reviewers for their valuable comments.

 

Below are the responses to the reviewers' comments concerning the comments posted.

 

1. The content of the article is interesting and concerns the modeling of a hand prosthesis with seven degrees of freedom and prototyping with the use of 3D Printing. The method of modeling and simulating elements based on FEM and with the use of topological optimization was also presented. The parameters of additive manufacturing using the Ultimaker device were described.

Authors' reply:

Thanks, new materials and findings have been added to increase the quality of the research

 

Table 3 shows the results obtained. It is important to mention that the value of interest is the maximum deformation since it considers the modulus of elasticity, which is a different property in each material. It is observed that the displacements vary in each case due to the different densities exhibited by each material. However, the maximum shear stress is similar since the same load is always applied to the same area.

 

Table 3 Numerical results of 7 D.O.F. prothesis with different materials

Material	Total displacement (mm)	Maximum shear stress (MPa)	Total deformation
Aluminum; 7075-O	1.0207	32.772	0.00042631
Stainless Steel; SAE 304	0.37987	32.299	0.0001781
Titanium; Ti-6Al-4V	0.64199	32.94	0.00026773
Stainless; AISI 1040- Standardized	0.36631	32.329	0.0001721
ABS	31.814	N/A	0.014786

 

2. The title of the article does not correspond to its content, a more appropriate title should refer to the modeling and simulation process of a hand prosthesis intended for production with incremental methods.

Authors' reply:

Thanks, The design and dynamics results are reported on [7, 8, 22]. This research tries to explain the necessity to use FEM analysis to optimize 3D Printing when a prosthesis is manufacturing. Also the special issue were this research had been sumbmited is 

3. In the article, the analysis of manufacturing costs is performed in a general manner, hence it should not be included in the title.

Authors' reply:

The low cost referes to In the begging, the prototype was made by ABS, the cost was around 1500 dollars of materials, the machine used to print all the 7 DOF Prosthesis was a Dimension SST 1200 machine. However, the cost was reduced by around 67% with this research. Therefore, I predict the cost of the prototype to be around $300 using PLA for the 3D printed parts and $200 for the spherical robot links used in the wrist and shoulder.

4. The quality of the drawings is average and poor in several places due to their size.

Authors' reply:

Done; the figures have been updated and increased the quality of all.

5. The literature is modest and insufficient and needs to be expanded.

Authors' reply:

Done; new information related to this research has been added.

 

Exist many prostheses to restore the normal functions of the missing body part. It is essential to design and fabricate them as per the patient's specifications. 3D printing technology provides a platform to fabricate any complex shaped polymeric parts economically based on a mechanism to deliver motion and action of upper limb and hands for children [9]. Also, it provides exciting new opportunities for upper-limb prosthetics, and validation is required before the many potential benefits can be realized in clinical practice. Thus far, there is limited evidence of using 3D Printing into upper-limb prostheses [10]. The finite element method obtained mechanical analysis of a practical and low-cost prosthetic hand. During the study, particular emphasis was set on the design process, including functional and technical requirements, correct material selection, and numerical techniques to reproduce the intended D.O.F. [11]. The prosthetic hand was assembled on a 3D printer using clear resin. This prosthetic hand provided the amputee's cosmetic, appearance and control sensitivity that did not attract much attention in society and positively affected the person [12]. Additive manufacturing for prosthetics sockets using clinical settings reduces costs [13]. The 3D model orthoses are commonly used to complement therapy and for various purposes, not only for the upper limb but also for almost all body parts [14]. 3D-printed is a low-cost method of producing sockets using clinical expertise to create well-fitting prosthetics [15]. An extensive range of prostheses has been 3D-printed, of which the majority are upper limb prostheses, the majority designed for children [16]. 3D Printing and Rapid Prototyping can contribute significantly to the manufacturing process of assistive technologies, mainly prostheses, streamlining development processes, and reducing product costs. In addition, 3D Printing has contributed to the execution of tailor-made and user-tailored parts, which is much faster and more accurate than the conventional manual prosthetic process [17]. An affordable and functional upper-limb prosthesis for transradial amputees was tested and validated. Also, its modular, intrinsic, and versatile design allows for its adaptation to the user's needs, such as providing alternate ways of gathering the user intent[18]. Analysis of print times and materials cost indicate that injection modeling is advantageous to 3D Printing due to lower cost and faster manufacture times [19]. The manufacturing process to assembly orthoses and prostheses have been analyzed in this field of the subject's morphology and accuracy of the final device, leading to a better rehabilitation process. Future development lines in this field will be based on the design of new structures and materials to improve comfort, which will grant the success of the new prosthetic aids.[20] A functional prototype of a cosmetic prosthesis was obtained. The dual extrusion process caused certain defects, which will be prevented in future manufacturing iterations of this type of product using slightly different manufacturing parameters [21].

 

Author Response File: Author Response.pdf

Reviewer 2 Report

In [1] there is not mentioned the percentage of 5,13%.

“The following proposed flow chart based on the literature (Figure 3) summarizes the general methodology used to evaluate the upper limb. “ – figure 3 is not a flow chart.

“Since the selected material is aluminum 750-O” – in figures 5,6,7 the material is Aluminum 7075-O.

The FEA is modeled on the shoulder joint with 3 DOF and the behavior of the other 4 DOF is not presented, there should be presented for all joints that have movement on the X and Z axis.

It is necessary to realize FEA for 6 bars mechanism (1 DOF).

It is not specified which links will be made of Aluminum 7075-O and which will be made by 3D printing.

“The prosthesis model proposed by the authors shown in Figure 1, was manufactured 50 in ABS [9]” – kindly check, as in Table 9 for manufacturing FDM the material is PLA.

The resolution of figure 8 is not good.

Figure 4 Application of the average load to the " X " axis – in this figure, the force works in plane XOZ. In Table 4. Reaction forces of the six-bar mechanism there are presented the results in plane XOY Fx, Fy. Which one is correct? Please realize a diagram with the standard symbols from each link, from each mechanism (Six-bar mechanism, Spheric mechanism, ball gripping mechanism) and maintain the results for axis in the entire study.

Figure 13. Spheric manipulator and Table 7. Reaction forces of the ball gripping mechanism – It is not clear which is the ball gripping mechanism.

The results for each binding site of interest are shown in Table 4 – the mechanism has six bars, but there are presented only 5 bars.

The results of each piece optimized and unoptimized are shown in Table 6 – the mechanism has six bars, but there are presented only 4

Line 171 Figure 17 is actually Figure 14 in the study. Kindly check and correct, as the number of figures needs to be revised.

Line 199 reference [17] is not included in the bibliography.

[7,8,9] are self-citations.

Author Response

REPLAY TO REVIEWER 2

 

Ref. No.: Applsci-1525756

Title: Low-cost manufacturing of an upper limb prosthesis with 7 degrees of freedom

Journal: Applied Sciences

Answer date: February 2^nd, 2022

Corresponding author: Torres-SanMiguel C.R.

Email: ctorress@ipn.mx

 

We thank the reviewers for their valuable comments.

 

Below are the responses to the reviewers' comments concerning the comments posted.

1. In [1] there is not mentioned the percentage of 5,13%.

 

Authors' reply:

Done; the reference is updated and it is changes the disability percentage to 4.9%.

 

2. “The following proposed flow chart based on the literature (Figure 3) summarizes the general methodology used to evaluate the upper limb. “ – figure 3 is not a flow chart.

 

Authors' reply:

Done, this sentence has been removed.

 

3. “Since the selected material is aluminum 750-O” – in figures 5,6,7 the material is Aluminum 7075-O.

 

Authors' reply:

Done; the correct material has been updated.

 

4. The FEA is modeled on the shoulder joint with 3 DOF and the behavior of the other 4 DOF is not presented, there should be presented for all joints that have movement on the X and Z axis.

 

Authors' reply:

The design of the arm prosthesis with 7 DOF distributes its movements as follows: 3 DOF in the shoulder, 1 DOF in the elbow, and 3 DOF in the wrist. As a result, the functional design of an upper limb prosthesis was conceived. First, the FEM analysis in the 7 DOF was carried out. Figures 5, 6, and 7 show the stress, strain, and displacement. The shoulder uses a spheric manipulator like, as shown in figure 1. Also, the wrist uses the same type of manipulator. Table 8 shows the FEM optimization of all links that corresponded to 3 DOF, table 6 shows the links of the 6 bars mechanism that corresponded to 1 DOF.

 

 

 

Figure 1. Spherical robot

 

 

Figure 2. Failure elements “Red circuls”

 

5. It is necessary to realize FEA for 6 bars mechanism (1 DOF).

 

Authors' reply:

 

Table 6 shows the FEM Analysis of the six bars mechanism.

 

6. It is not specified which links will be made of Aluminium 7075-O and which will be made by 3D printing.

 

Authors' reply:

 

All the links used in the spherical robot and the 6 bars mechanism are going to manufacture with aluminum 7075-O

7. “The prosthesis model proposed by the authors shown in Figure 1, was manufactured 50 in ABS [9]” – kindly check, as in Table 9 for manufacturing FDM the material is PLA.

 

Authors' reply:

It is correct; In the begging, the prototype was made by ABS, the cost was around 1500 dollars of materials, the machine used to print all the 7 DOF Prosthesis was a Dimension SST 1200 machine. However, the cost was reduced by around 67% with this research. Therefore, we predict the cost of the prototype to be around $300 using PLA for the 3D printed parts and $200 for the spherical robot links used in the wrist and shoulder.

 

8. The resolution of figure 8 is not good.

 

Authors' reply:

 

Done, the figure has been changed

 

9. Figure 4 Application of the average load to the " X " axis – in this figure, the force works in plane XOZ. In Table 4. Reaction forces of the six-bar mechanism there are presented the results in plane XOY Fx, Fy. Which one is correct? Please realize a diagram with the standard symbols from each link, from each mechanism (Six-bar mechanism, Spheric mechanism, ball gripping mechanism) and maintain the results for axis in the entire study.

 

Authors' reply:

 

Done, figure 4 is corrected with table 4. The following figure can clarify the particular position of the prosthesis.

 

Figure 3. a)Frontal View, b)Left view, c)Isometric view and d) Top view

 

10. Figure 13. Spheric manipulator and Table Reaction forces of the ball gripping mechanism – It is not clear which is the ball gripping mechanism.

 

Authors' reply:

            Figure 4a shows a spherical parallel robot, and figure 4b shows the shoulder design prototype used in the 7 DOF prosthesis. The boundary conditions fix the pins to obtain the forces with Solidworks® motion analysis.

 

                             

Figure 4. a) Spherical parallel robot, b) Shoulder design prototype

 

11. The results for each binding site of interest are shown in Table 4 – the mechanism has six bars, but there are presented only 5 bars.

 

Authors' reply:

 

The blue bar is an imaginary element that only is used to assess the movements of another 5 links, so because of that is not analyzed with FEM.

Figure 5. Highlighting 6 bars mechanism

 

 

12. The results of each piece optimized and unoptimized are shown in Table 6 – the mechanism has six bars, but there are presented only 4

 

Authors' reply:

 

Done; the numerical analysis of the missing bar is added.

 

13. Line 171 Figure 17 is actually Figure 14 in the study. Kindly check and correct, as the number of figures needs to be revised.

 

Authors' reply:

Done; figures 13 to 17 have been renumbered.

 

14. Line 199 reference [17] is not included in the bibliography.

 

Authors' reply:

Done; reference has been added.

 

15. [7,8,9] are self-citations.

 

Authors' reply:

The self-citations are required to explain previous work. The design and dynamic analysis were carried out and reported in the published articles by a Ph.D. student.

Author Response File: Author Response.pdf

Reviewer 3 Report

This work is very interesting, but there are some problems that the authors should solve, listed as follows:

1. In line 41 you mention a structural static analysis, mention why analyze statically? What is the advantage? Since a dynamic analysis could offer more information, with the accelerations and moments of inertia.
2. In line 42 you mention a load of 5 N. Why did you select this load?
3. Mention why the materials in Table 1 were selected as candidates for comparison. When analyzing table 1, it could be understood that the winner is aluminum, due to what is mentioned in line 61: durability, lightness, and more resistance than ABS, in addition to machinability. where did you get the data in table 1?
4. The mass indicated on line 51 and line 72 do not match and mention the same thing. In addition, to unify the units in one they mention "Kg" and in another "gr".
5. In table 1 and table 2 the density of aluminum is different, what is the reason for this small change? In addition, the density data appear in table 1. What is the reason for repeating them in table 2?
6. Line 76 indicates "An adaptive mesh of 83,405 elements and 137,630 nodes was proposed." What is the reason for that number of elements and nodes?
7. Line 91 indicates an aluminum with an incorrect designation number.
8. Standardize line 94 and line 96 script fonts the designation “7075-O” on one line is italicized and on the other, it is not.
9. Improve the quality of figure 8 indicate if they are 1, 2, or 3 diagrams? Why the separation of the diagram at "A"?
10. In table 4 “Size = XX” you could use a resultant vector notation with direction.
11. Table 5 repeats data from tables 1 and 2, it only indicates 2 new values.
12. Discuss further your results from Tables 6 and 8.
13. In line 140 the safety factor is not clear, citation [13] is for materials for machining.
14. How are figure 12 and figure 4 different?
15. Do not cut figure 7.
16. In Analyzes 6 and 8, why are bolts not considered? does it affect or not?
17. In line 171 it mentions figure 17, which does not exist.
18. In line 174, is the reference 13 or 14? does not match the job brief.
19. Give a more detailed explanation of figure 14, improve the quality of the image, and mention where did you get the images?
20. There is no sequence of figures. There is no sequence of figures. Figure 14 and the next figure is 18, in addition, to figure 20 and the next figure is 23.
21. In section 4.3 a CNC machine is proposed (3 and 4 axes) (line 215), the machining proposed is correct, however, if we use a 5-axis machine, the proposed and optimized parts of tables 6 and 8 can be machined, why was it not thought of?
22. Figure 20 explains why a material clamping zone is not considered, since the analysis is a bit ambiguous?
23. It is recommended to cite more works and to be able to validate and compare with other authors, as far as possible try to change the citations of technical pages or reinforce them.

Author Response

REPLY TO REVIEWER 3

 

Ref. No.: Applsci-1525756

Title: Low-cost manufacturing of an upper limb prosthesis with 7 degrees of freedom

Journal: Applied Sciences

Answer date: February 2^nd, 2022

Corresponding author: Torres San Miguel C.R.

Email: ctorress@ipn.mx

 

We thank the reviewers for their valuable comments.

 

Below are the responses to the reviewers' comments concerning the comments posted.

This work is very interesting, but there are some problems that the authors should solve, listed as follows:

1. In line 41 you mention a structural static analysis, mention why analyze statically? What is the advantage? Since a dynamic analysis could offer more information, with the accelerations and moments of inertia.

 

Authors' reply:

Done; the design and dynamic analysis were carried out and reported in the published articles [7, 8, 22], which is not the scope of this research. Static analyses were carried out to find the links thickness or the elementary geometry to be increased or modified. This research shows the optimization of the weakest elements that could present failures.

 

1. In line 42 you mention a load of 5 N. Why did you select this load?

 

Authors' reply:

Thanks; the average force that an adult can sustain in a position when the arm is extended horizontally.

 

1. Mention why the materials in Table 1 were selected as candidates for comparison. When analyzing table 1, it could be understood that the winner is aluminum, due to what is mentioned in line 61: durability, lightness, and more resistance than ABS, in addition to machinability. where did you get the data in table 1?

 

Authors' reply:

Done; The information was recapitulated from Material Properties, Ed. Mc Graw Hill, 2018.

 

 

1. The mass indicated on line 51 and line 72 do not match and mention the same thing. In addition, to unify the units in one they mention "Kg" and in another "gr".

 

Authors' reply:

Done; units have been homogenized

 

1. In table 1 and table 2 the density of aluminum is different, what is the reason for this small change? In addition, the density data appear in table 1. What is the reason for repeating them in table 2?

 

Authors' reply:

Done; Tables 1 and 2 have been merged

 

1. Line 76 indicates "An adaptive mesh of 83,405 elements and 137,630 nodes was proposed." What is the reason for that number of elements and nodes?

 

Authors' reply:

Done; It is due to the type of element used "Solid 186/187" to generate the prosthesis mesh.

 

1. Line 91 indicates an aluminum with an incorrect designation number.

 

Authors' reply:

Thanks, the designation number has been corrected.

 

1. Standardize line 94 and line 96 script fonts the designation “7075-O” on one line is italicized and on the other, it is not.

 

Authors' reply:

Done; fonts have been homogenized

 

1. Improve the quality of figure 8 indicate if they are 1, 2, or 3 diagrams? Why the separation of the diagram at "A"?

 

Authors' reply:

Done; the figure has been changed, and right now is only 1 figure.

 

1. In table 4 “Size = XX” you could use a resultant vector notation with direction.

 

Authors' reply:

Done; has been added a vector notation in all the figures on table 4

 

1. Table 5 repeats data from tables 1 and 2, it only indicates 2 new values.

 

Authors' reply:

Done; Table 1 and Table 2 were merged. Table 5 has important values to carry out the numerical analysis of the prosthesis.

 

1. Discuss further your results from Tables 6 and 8.

 

Authors' reply:

Done; a discussion section has been added to discuss some relevant findings

“According to the finite element calculation results shown in Figures 5, 6, and 7, it is evident that the pieces that contemplate the shoulder area exhibit more significant stress concerning the rest of the pieces. This makes sense if it is considered that the prosthetic shoulder should support the whole structure of the prosthesis through the spherical manipulator that would emulate the articular loads that the human shoulder area receives. Therefore, topological optimization was performed to increase the performance of the transhumeral prosthesis mechanism from the elbow to the shoulder. ANSYS Workbench® program was used to corroborate the non-optimized and optimized pieces' stress, as shown in tables 6 and 8.”

“Topological optimization seeks to obtain the maximum or minimum stiffness, that is, to minimize or maximize the deformation energy with a volume restriction. In other words, it is the reduction of the final weight of the structural, mechanical element, preserving its stiffness and functionality. This formulation finds the relative density distribution of material within a domain on a grid of finite elements called design isotropic solid microstructures whose dimensionless value must be between zero and one, where zero indicates that material is removed and one indicates that material is required. For example, in the central column of tables 6 and 8, the topological optimization performed on the links located in different parts of the prosthetic device shows a reduction of material, which leads to a reduction of machining process hours.”

 

1. In line 140 the safety factor is not clear, citation [13] is for materials for machining.

 

Authors' reply:

Done; the reference has been updated. Right now, the reference is the correct

 

1. How are figure 12 and figure 4 different?

 

Authors' reply:

Done; Figure 12 has been eliminated.

 

1. Do not cut figure 7.

 

Authors' reply:

Done; The figure has a zoom-in to appreciate the specific area that presents the Maximum unit deformation of the material, this why the figure is cut.

 

1. In Analyzes 6 and 8, why are bolts not considered? does it affect or not?

 

Authors' reply:

Done; The parametrization of the model was performed by simulating the load conditions produced by applying a force in hand. The mechanical contact between the links and the bolts was defined as "bonded" because the tightening action of the bolds restricts the relative movement between their surfaces and simulates the boundary conditions produced by the bolt.

 

1. In line 171 it mentions figure 17, which does not exist.

 

Authors' reply:

Done; figures 13 to 17 have been renumbered.

 

1. In line 174, is the reference 13 or 14? does not match the job brief.

 

Authors' reply:

Done; the reference has been updated. Right now, the reference is the correct

 

1. Give a more detailed explanation of figure 14, improve the quality of the image, and mention where did you get the images?

 

Authors' reply:

Done; the figure has been changed, and the images have been taken from the following reference. “Sandvik Coromant, E-Learning de Conocimientos de Mecanizado, Sandvik Coromant, 2019”. The author had done the image.

https://www.sandvik.coromant.com/es-es/services/education/pages/e-learning.aspx

 

1. There is no sequence of figures. There is no sequence of figures. Figure 14 and the next figure is 18, in addition, to figure 20 and the next figure is 23.

 

Authors' reply:

Done; figures 13 to 17 have been renumbered.

 

1. In section 4.3 a CNC machine is proposed (3 and 4 axes) (line 215), the machining proposed is correct, however, if we use a 5-axis machine, the proposed and optimized parts of tables 6 and 8 can be machined, why was it not thought of?

 

Authors' reply:

Done; The criterion to decide if the part requires the fourth axis is established by means of the Z axis, that is, if the part requires a rotation to perform a machining operation that is not possible to achieve by entering the cutting tool perpendicular to the surface of the block of material, it is necessary the implementation of a fourth axis that allows the rotation of the part, the axis can be with respect to X, Y or Z. To understand this phenomenon, in the square type part (Figure 1) one can observe on the left (Figure 1a) a part that has a box in the xy plane which can be processed with a cutting tool perpendicular to that plane, i.e. one that has feed movements in the Z axis; however, when trying to make the holes that are in the zx plane it is impossible since the cutting tool cannot rotate to that plane; however, with the implementation of a fourth axis the part can be rotated 90° on the x axis (Figure 1b) to continue with the corresponding operations.

X

Y

Z

a)

X

Y

Z

X

Y

Z

b)

90° Rotation on axis X

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1.- Squared part to be manufactured with fourth axis on the X axis. a) Normal position. b) Position with rotation of the part on the X axis at 90°.

 

In this case for the machining of allthe links of the prothesis design, is required only 4 axis.

 

1. Figure 20 explains why a material clamping zone is not considered, since the analysis is a bit ambiguous?

 

Authors' reply:

Done; The wizard was used to assemble the part, align the Z-axis perpendicular to a favorable horizontal surface and proceed to align the X-axis by means of two points of a straight edge, then select the type of shape of the material to be machined such as a cylindrical block, rectangular or user-defined by the featureCAM® software. In this case, the part can be generated from a rectangular prism. Next, the program is asked to calculate the block's dimensions with the possibility of adding an over-material to the part (Figure 2) as marked in the green rectangle in the image. Hence, the program is responsible for setting the dimensions in millimeters for the block as shown in the blue rectangle, then proceeds to declare a reference origin point (setup) highlighted in yellow in the image. Usually, the center point of the part is used. However, since a fourth axis is not required, the software must specify this condition to conclude the part import process.

 

Y

Z

X

Y

Z

X

Figure 2.- Starting material block configuration

 

1. It is recommended to cite more works and to be able to validate and compare with other authors, as far as possible try to change the citations of technical pages or reinforce them.

Authors' reply:

Done; new information related to this research has been added.

 

Exist many prostheses to restore the normal functions of the missing body part. It is essential to design and fabricate them as per the patient's specifications. 3D printing technology provides a platform to fabricate any complex shaped polymeric parts economically based on a mechanism to deliver motion and action of upper limb and hands for children [9]. Also, it provides exciting new opportunities for upper-limb prosthetics, and validation is required before the many potential benefits can be realized in clinical practice. Thus far, there is limited evidence of using 3D Printing into upper-limb prostheses [10]. The finite element method obtained mechanical analysis of a practical and low-cost prosthetic hand. During the study, particular emphasis was set on the design process, including functional and technical requirements, correct material selection, and numerical techniques to reproduce the intended D.O.F. [11]. The prosthetic hand was assembled on a 3D printer using clear resin. This prosthetic hand provided the amputee's cosmetic, appearance and control sensitivity that did not attract much attention in society and positively affected the person [12]. Additive manufacturing for prosthetics sockets using clinical settings reduces costs [13]. The 3D model orthoses are commonly used to complement therapy and for various purposes, not only for the upper limb but also for almost all body parts [14]. 3D-printed is a low-cost method of producing sockets using clinical expertise to create well-fitting prosthetics [15]. An extensive range of prostheses has been 3D-printed, of which the majority are upper limb prostheses, the majority designed for children [16]. 3D Printing and Rapid Prototyping can contribute significantly to the manufacturing process of assistive technologies, mainly prostheses, streamlining development processes, and reducing product costs. In addition, 3D Printing has contributed to the execution of tailor-made and user-tailored parts, which is much faster and more accurate than the conventional manual prosthetic process [17]. An affordable and functional upper-limb prosthesis for transradial amputees was tested and validated. Also, its modular, intrinsic, and versatile design allows for its adaptation to the user's needs, such as providing alternate ways of gathering the user intent[18]. Analysis of print times and materials cost indicate that injection modeling is advantageous to 3D Printing due to lower cost and faster manufacture times [19]. The manufacturing process to assembly orthoses and prostheses have been analyzed in this field of the subject's morphology and accuracy of the final device, leading to a better rehabilitation process. Future development lines in this field will be based on the design of new structures and materials to improve comfort, which will grant the success of the new prosthetic aids.[20] A functional prototype of a cosmetic prosthesis was obtained. The dual extrusion process caused certain defects, which will be prevented in future manufacturing iterations of this type of product using slightly different manufacturing parameters [21].

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The author took into account most of the previously mentioned comments, but the title of the article still does not correspond to its content. I propose to change the title or refer to the title in the summary. It should be shown how the total costs are and whether they are really low compared to other solutions for the production of prostheses.

Author Response

REPLY TO REVIEWER 1

 

Ref. No.: Applsci-1525756

Title: Low-cost manufacturing of an upper limb prosthesis with 7 degrees of freedom

Journal: Applied Sciences

Answer date: February 11^Th, 2022

Corresponding author: Torres San Miguel C.R.

Email: ctorress@ipn.mx

 

We thank the reviewers for their valuable comments.

 

Below are the responses to the reviewers' comments concerning the comments posted.

 

1. The author took into account most of the previously mentioned comments, but the title of the article still does not correspond to its content. I propose to change the title or refer to the title in the summary. It should be shown how the total costs are and whether they are really low compared to other solutions for the production of prostheses

Authors' reply:

 

Done. The article's title has been changed and was used the proposed by reviewer 1 in the previous review. Now the new title is “Modeling and simulation process of an upper limb prosthesis aimed for production through incremental methods”

Likewise, in the discussion section is was added the following paragraph the cost of the prosthesis: “The prototype was made with ABS, and the cost was around 1500 dollars of 3D materials. The machine used to print the entire  7-DOF prosthesis was a Dimension SST 1200. The cost was reduced by around 67% with this research. Therefore, the prototype is estimated to be around 300 dollars using PLA for the 3D printed parts and 200 dollars for the spherical robot links used in the wrist and shoulder with aluminum”

 

Author Response File: Author Response.pdf

Reviewer 2 Report

1) Also, there are many English usage/syntax problems ("The following flow chart (Figure 15) is (Figure 14)...") - too many to list here.  To make sure that the paper and its results are accessible to the majority of readers, the paper should be revised to conform to standard English grammar.

2) The 6-bars mechanisms has two critical position, specify why the second extreme position was not analyzed?

3) I recommend for bibliografy the manuscris "Concept, Design, Initial Tests and Prototype of Customized Upper limb Prosthesis" from Jurnal Aplied Science.

4) Specify in conclusions aspects related to ABS / PLA cost to justify the low manufacturing

The manuscript fall within the journal’s aims and scope as well as does fit within the declared topic " 3D Printing in Bio-Medical Applications". The paper in my opinion is interest to the audience of Applied Science. That is why I recommend it for publication in Applied Science.

Author Response

REPLY TO REVIEWER 2

 

Ref. No.: Applsci-1525756

Title: Low-cost manufacturing of an upper limb prosthesis with 7 degrees of freedom

Journal: Applied Sciences

Answer date: February 2^nd, 2022

Corresponding author: Torres-SanMiguel C.R.

Email: ctorress@ipn.mx

 

We thank the reviewers for their valuable comments.

 

Below are the responses to the reviewers' comments concerning the comments posted.

• Also, there are many English usage/syntax problems ("The following flow chart (Figure 15) is (Figure 14)...") - too many to list here. To make sure that the paper and its results are accessible to the majority of readers, the paper should be revised to conform to standard English grammar.

 

Authors' reply:

All figures, tables, and references have been checked and highlighted to avoid errors and ensure they are mentioned in the text. Likewise, the writing has been revised, and typos have been eliminated.

 

• The 6-bars mechanisms has two critical position, specify why the second extreme position was not analyzed?

 

Authors' reply:

It was observed during the experimental tests that the position analyzed in this research work is the one that presented a failure during its movements. In a static position, the configuration presents a more significant moment, and it is estimated that the most significant magnitude that can be presented during the prosthesis use is generated according to the 5 N mass raised in the palm. So only that position was contemplated. Thanks to their observation, future analyzes will be carried out with different working positions of the prosthesis.

 

• I recommend for bibliografy the manuscris "Concept, Design, Initial Tests and Prototype of Customized Upper limb Prosthesis" from Jurnal Aplied Science.

 

Authors' reply:

 

The reference has been added and discussed to improve the work.

 

4) Specify in conclusions aspects related to ABS / PLA cost to justify the low manufacturing

 

Authors' reply:

 

The next paragraph has been added int the conclusions

 

“The prototype was made with ABS, and the cost was around 1500 dollars of 3D materials. The machine used to print the entire  7-DOF prosthesis was a Dimension SST 1200. The cost was reduced by around 67% with this research. Therefore, the prototype is estimated to be around 300 dollars using PLA for the 3D printed parts and 200 dollars for the spherical robot links used in the wrist and shoulder with aluminum”

Author Response File: Author Response.pdf