Analytical, Numerical and Experimental Analysis of a Positive Displacement Cam Mechanism—A Case Study

Round 1

Reviewer 1 Report

Dear Authors!

Sincere congratulations for this wery highly significant paper.

My analysis  regarding the paper and somje suggestions are comprised in the attachment.

Comments for author File: Comments.pdf

I am not qualified to comment the quality of English language used, till I'm not Licenciated in this domain. I understand very well the sense of the phrases. In som places I made some recommendations.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is current, and published results are interesting. In the Introduction, paper dealing with similar issues is analyzed in detail. The authors of the paper can be criticized for using a rigid linearization of the model in the Materials and Methods section. The results presented then show a significant difference with reality. It would be more appropriate to use a non-linear dynamic model or equivalent substitution.

I request the following addition from the authors:

 1. In the Materials and Methods section, excuse the reasons for linearization in more detail.

2. The line 277 "DOF (degrees of freedom)" and line 324 "DOF (degree of mobility), " must be uniform.

3. For the validation of the experimental section, it is necessary to add a photo of the measuring stand, devices and cam.

4. Fig.11a) and c) used units (V) but the measured quantity is aE. – it is necessary to repair.

5. I suggest adding a table or a graph that shows a comparison of the results by expressing the error between the implemented models and the experiment.

6. The Fig. 12, 13, 14 are incomprehensible. Quantities are wrong labelled and wrong define, graph descriptions are incomprehensible. w1= ct, w1=var - what is? if the quantity w2 or e2?

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper is inadequately structured and very poorly written. 

The title is not proper:  "Geometrical Parameters and Technological Conditions as Influence Factors on Dynamic Behavior of Cam Mechanisms" There is a promise of generality "... of cam mechanisms" while the paper deals with a certain type of positive displacement cam used in a textile equipment.  "Technological Conditions" were never defined in the main text!  I would recommend instead the title "Analytical, numerical and experimental analysis a positive-displacement cam mechanism - a case study"

The Abstract and Introduction are poorly written. The literature review is only marginally relevant - please review instead representative titles from:  

https://scholar.google.com/scholar?hl=en&as_sdt=7%2C44&q=follower+jump&btnG=

https://scholar.google.com/scholar?hl=en&as_sdt=7%2C44&q=%22face+cam%22+OR+%22groove+cam%22&btnG=

https://scholar.google.com/scholar?hl=en&as_sdt=7%2C44&q=cam+dynamics&btnG=

>> Further criticisms: 

Photographs of the actual mechanism and of the experimental setup are expected. 

The plots in figures 7, 8, 9, 12, 13 and 14 do not show Y-axis units. 

The FEA model is of the cam and roller only.  On the real mechanism, contact surfaces are hardened. The authors may want to explain why a structural steel material (which is typically soft) was adequate.  

I see no correlation between the experiment and the analytical and numerical models (Figures 12, 13, 14). 

I would recommend the authors to study carefully works by native English speakers, and adopt the proper terminology.  Examples: "calculation" NOT "calculus"; "diagram" NOT "scheme"; "jerk" NOT "pulse"; "higher kinematic pair" NOT "superior coupling"; "differential equation of motion" NOT "motion differential equation"; "the desired initial position" NOT "the wanted starting position" etc. etc.  

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors made changes to improve the quality of the paper. It is necessary to more attention to the following:

1.Figures 11, 12, 13, 14 are still incomprehensible. Quantities are incorrectly marked and incorrectly defined, graph descriptions are incomprehensible. For example (in Fig. 11. x-axis time (s) 0.1 ... 0.5), but Fig. 12 time (s) 2.00E-2) - must be uniform and correct.
For example fig.11a), c)  x-axis - mising units, unreadable values, etc.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

"Analytical, Numerical and Experimental Analysis OF a Positive- Displacement Cam Mechanism - a Case Study"  note the missing "OF" 

Technological force is a term used in Marketing - just Google it.  Use "load force" instead.  

"Technological conditions" appear to have been the cam-follower backlash j.  In some models it was taken zero. When not zero, what was the actual value of j ?

VERY IMPORTANT:  Provide a picture of the experimental setup WITH EXPLANATIONS OF EACH COMPONENT, and of the entire mechanism as it occurs on the actual textile machine. 

In the experiment it appears that the cam is slowing fast (figure 13). This is likely because of the inertia differences between the experiment and the simulation.  In the FEA model you did not include inertia of the follower linkage at all.  

I am not in favor for this paper to be accepted for publication.  Missing details about the experiment, and overall the investigation lacks purpose.  

English should be improved for clarity.  

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

The paper can be presented in a modified form.

Author Response

Please see the attachment

Author Response File: Author Response.pdf