Development of Connection Technology between Multi-Point Press and Flexible Mold for Manufacturing Free-Form Concrete Panel
Round 1
Reviewer 1 Report
The manuscript is well written and clear.
But this paper needs to be revised. Here I give the comments.
In the literature review, it's only a few papers that are very recent (2019-22). The rest of them are quite old. Maybe the authors can update this with more up-to-date results?
Lines 39-44: This sentence should be changed. Hard to understand.
Line 108: What aspect of the mold is modified, please elaborate.
Line 153: ‘injection’ to change to ‘pouring’.
Line 162: ‘skills’ to change to ‘technologies’.
Line 298: ‘Curve’ to change to ‘Curved surface’. Similarly hereinafter.
Line 300: Lower the rods of what? Please elaborate.
Lines 329-336: The concrete mix ratio is not introduced in detail. Please elaborate.
For the experimental setup in section 4, is there any standard that has been followed?
Author Response
Ms. Ref. No.: buildings-1694904
The authors would like to first thank the editor who allowed us opportunities to revise and resubmit the paper. We also sincerely appreciate the anonymous reviewer who provided thorough reviews and valuable comments to help us improve the manuscript. We strongly believe that in the revision we have fully addressed all the reviewer’s comments and concerns and carefully revised the manuscript based on the feedback we have received. Please see the followings below responding to reviewer’s comments.
Reviewer comments. The manuscript is well written and clear.
But this paper needs to be revised. Here I give the comments.
In the literature review, it's only a few papers that are very recent (2019-22). The rest of them are quite old. Maybe the authors can update this with more up-to-date results?
Reply. Paper about free form concrete panels have been published recently. Previous literature differs from this study.
Reviewer comments. Lines 39-44: This sentence should be changed. Hard to understand.
Reply. We revised the sentence as below.
Original. [Line 39-44] The recently completed National Museum of Qatar used about 76,000 free-form concrete panels to fabricate the 316 disks that build up the structure
Revised. [Line 39-44] About 76,000 free-form concrete panels was used to fabricate the 316 roof disks of the National Museum of Qatar.
Reviewer comments. Line 108: What aspect of the mold is modified, please elaborate.
Reply. We revised the sentence as below.
Original. [Line 39-44] The recently completed National Museum of Qatar used about 76,000 free-form concrete panels to fabricate the 316 disks that build up the structure
Revised. [Line 39-44] About 76,000 free-form concrete panels was used to fabricate the 316 roof disks of the National Museum of Qatar.
Reviewer comments. Line 153: ‘injection’ to change to ‘pouring’.
Reply. We revised the sentence as below.
Original. [Line 153] The fabrication process of free-form concrete panels was divided into four steps: connection, injection, compression and curing, and removal.
Revised. [Line 153] The fabrication process of free-form concrete panels was divided into four steps: connection, pouring, compression and curing, and removal.
Reviewer comments. Line 162: ‘skills’ to change to ‘technologies’.
Reply. We revised the sentence as below.
Original. [line 162] Creating free-form concrete panels requires highly advanced skills and the quality varies according to the skills of workers and the accuracy of machines.
Revised. [1ine 162] Creating free-form concrete panels requires highly advanced technologies and the quality varies according to the skills of workers and the accuracy of machines.
Reviewer comments. Line 298: ‘Curve’ to change to ‘Curved surface’. Similarly hereinafter.
Reply. We revised the sentence as below.
Original. [line 298] Considering the fixed-type curve as in Fig. 8, Curve 1 showed the greatest error at the edge of shape.
Revised. [line 298] Considering the fixed-type curve as in Fig. 8, Curved surface 1 showed the greatest error at the edge of shape.
Reviewer comments. Line 300: Lower the rods of what? Please elaborate.
Reply. We revised the sentence as below.
Original. [line 300] Due to the difference in the height of rods, the silicon’s elasticity straightened the shape panel and lowered the rods.
Revised. [line 300] Due to the difference in the height of rods, the silicon’s elasticity straightened the shape panel and lowered the rods of CNC.
Reviewer comments. Lines 329-336: The concrete mix ratio is not introduced in detail. Please elaborate.
Reply. We inserted information of the mixing ratio of concrete.
Added. [line 339] The concrete used for panel production is fiber-reinforced concrete with a 1:1 mixture of cement and sand.
Reviewer comments. For the experimental setup in section 4, is there any standard that has been followed?
Reply. We had been looking for a lot of information about the experiment. However, there are no regulations or standards for that experiment.
Reviewer 2 Report
Dear Authors,
I have read your paper with attention and pleasure. In my opinion, the manuscript titled Development of connection technology between multi-point press and flexible mold for manufacturing free-form concrete panel presents original research and could be interesting for readers of the Buildings MDPI Journal.
The article concerns the problem of free-form concrete building technology, which is very important for innovation. The use of this technology can be very expensive and lead to large-scale exceedances of the estimated construction costs, examples of which were presented by the authors in the introduction.
The article presents the results of analyzes concerning the application of the connection technology of detachable shape part. The authors presented the results of the analysis of the effectiveness of the proposed technology, discussing the results of the curvature test and free-form concrete panel fabrication test.
The motivation is clear. The object of study, as well as the results, are comprehensively described providing valuable conclusions.
The paper is organised in a logical manner. The state of art covers the main results in the field. The contributions of the paper are clearly stated in the Introduction chapter.
I have no objections to recommend publishing this paper. However, due to the listed below drawbacks, my recommendation is "Accept after minor revision". In my opinion, several aspects require clarification. Please revise and add some comments and improvements according to the following:
- there are no predefined units of Shape error of fixed type (Fig. 8) and Shape error of detachable type (Fig. 9) as well as in Fig. 11 and Fig. 13; please add the unit in the legend or in the figures caption
- in my opinion, the error should be defined as an absolute value with the determination whether it is above or below the standard shape, the use of negative error values is misleading
- how does the thickness of the panel affect the errors obtained, what is the maximum size of the panels that can be achieved using the proposed connection technology of detachable shape part? please comment on this - does the connection technology of detachable shape part presented in the article limit the thickness of the panels? is it possible to determine the optimal thickness of the panels from the point of view of the minimum shape error?
Author Response
Reviewer 2.
Ms. Ref. No.: buildings- 1694904
The authors would like to first thank the editor who allowed us opportunities to revise and resubmit the paper. We also sincerely appreciate the anonymous reviewer who provided thorough reviews and valuable comments to help us improve the manuscript. We strongly believe that in the revision we have fully addressed all the reviewer’s comments and concerns and carefully revised the manuscript based on the feedback we have received. Please see the followings below responding to reviewer’s comments.
Reviewer comments.
I have read your paper with attention and pleasure.
In my opinion, the manuscript titled Development of connection technology between multi-point press and flexible mold for manufacturing free-form concrete panel presents original research and could be interesting for readers of the Buildings MDPI Journal.
The article concerns the problem of free-form concrete building technology, which is very important for innovation. The use of this technology can be very expensive and lead to large-scale exceedances of the estimated construction costs, examples of which were presented by the authors in the introduction.
The article presents the results of analyzes concerning the application of the connection technology of detachable shape part. The authors presented the results of the analysis of the effectiveness of the proposed technology, discussing the results of the curvature test and free-form concrete panel fabrication test.
The motivation is clear. The object of study, as well as the results, are comprehensively described providing valuable conclusions.
The paper is organised in a logical manner. The state of art covers the main results in the field. The contributions of the paper are clearly stated in the Introduction chapter.
I have no objections to recommend publishing this paper. However, due to the listed below drawbacks, my recommendation is "Accept after minor revision". In my opinion, several aspects require clarification. Please revise and add some comments and improvements according to the following:
Reviewer comments. there are no predefined units of Shape error of fixed type (Fig. 8) and Shape error of detachable type (Fig. 9) as well as in Fig. 11 and Fig. 13; please add the unit in the legend or in the figures caption in my opinion, the error should be defined as an absolute value with the determination whether it is above or below the standard shape, the use of negative error values is misleading
Reply. We added units in the caption of the figure.
Original. [Figure 8] Shape error of fixed type
Revised. [Figure 8] Shape error of fixed type (unit: mm)
Original. [Figure 9] Shape error of detachable type
Revised. [Figure 9] Shape error of detachable type (unit: mm)
Original. [Figure 11] Shape error of mold curve according to the position of silicon cap
Revised. [Figure 11] Shape error of mold curve according to the position of silicon cap (unit: mm)
Original. [Figure 13] Shape error of free-form concrete panel in repeated fabrication
Revised. [Figure 13] Shape error of free-form concrete panel in repeated fabrication (unit: mm)
Reviewer comments. how does the thickness of the panel affect the errors obtained, what is the maximum size of the panels that can be achieved using the proposed connection technology of detachable shape part? please comment on this - does the connection technology of detachable shape part presented in the article limit the thickness of the panels?
Reply. Thank you for the good question. As the thickness of the panel increases, the occurrence of errors is expected to increase. However, since the panel is not a structural material, I think that a thickness of 20mm will be sufficient. Insulation will be installed inside the concrete panel.
Reviewer comments. is it possible to determine the optimal thickness of the panels from the point of view of the minimum shape error?
Reply. We conducted the experiment after setting the appropriate thickness of the panel to 20mm. The reviewer's questions will help us in our next research. We will do various experiments on the optimal thickness of the panel.
Reviewer 3 Report
Comments and Suggestions for Authors
The issues are presented in the article: „Development of connection technology between multi-point press and flexible mold for manufacturing free-form concrete panel” are interesting. This study developed a connection technology of detachable shape part that can be applied to the existing multi-point Computer Numerical Control (CNC) to enhance the accuracy of fabrication. The accuracy of the technology was verified by curva ture test and free-form concrete panel fabrication test.
The article „Development of connection technology between multi-point press and flexible mold for manufacturing free-form concrete panel” presents well planned experimental program.
The paper is relatively in good format. Thus, the reviewer is glad to consider again this manuscript for publication after the authors properly address the below comments.
Comments:
- Please include some significant results in terms of quantitative form in the abstract.
- Please, provide the standard test methods used for the experiments. The methodology of "Free-form concrete panel fabrication and quality test process" is unclear. Preparation of samples for testing and the results are debatable. What standards did the methodology and testing machine meet? There is no statistical analysis. You should comment on that.
- Figure 10. Shape engineering and curve forming, (c) Calculating moving values of rods - there are many unnecessary details and small view.
- The paper can benefit from a minor editorial work up to check up spelling and any grammatical issues.
- My main suggestion is to check thoroughly the text, regarding both the language and the information provided in Section 5. "Conclusion”. The conclusions can be improved by citing in bullet format the key finds and any issues that may have added to improving or affected the outcome of the results. The Conclusions should be completely rewritten to include more specific information.
Author Response
Ms. Ref. No.: buildings- 1694904
The authors would like to first thank the editor who allowed us opportunities to revise and resubmit the paper. We also sincerely appreciate the anonymous reviewer who provided thorough reviews and valuable comments to help us improve the manuscript. We strongly believe that in the revision we have fully addressed all the reviewer’s comments and concerns and carefully revised the manuscript based on the feedback we have received. Please see the followings below responding to reviewer’s comments.
Reviewer comments.
The issues are presented in the article: „Development of connection technology between multi-point press and flexible mold for manufacturing free-form concrete panel” are interesting. This study developed a connection technology of detachable shape part that can be applied to the existing multi-point Computer Numerical Control (CNC) to enhance the accuracy of fabrication. The accuracy of the technology was verified by curvature test and free-form concrete panel fabrication test.
The article „Development of connection technology between multi-point press and flexible mold for manufacturing free-form concrete panel” presents well planned experimental program.
The paper is relatively in good format. Thus, the reviewer is glad to consider again this manuscript for publication after the authors properly address the below comments.
Reviewer comments. Please include some significant results in terms of quantitative form in the abstract.
Reply. We revised the abstract as below. The limitation of shape error is presented clearly in the abstract.
Original. [Abstract] Many studies have been conducted for the accuracy of free-form concrete panel fabrication, but there still are errors in the process of fabrication. This study developed a connection technology of detachable shape part that can be applied to the existing multi-point Computer Numerical Control (CNC) to enhance the accuracy of fabrication. The detachable type can place a silicon plate on top of the rod without additional fixtures. The accuracy of the technology was verified by curvature test and free-form concrete panel fabrication test. Three curves were created to compare the discrepancies between the designed shapes and the fabricated shapes through qual-ity test. As a result, the detachable type decreased the error by up to 2 mm. The error of the mold curve was within 3 mm, which was the allowable error suggested by the current study. Also, a panel was fabricated to analyze the error to verify the rigidity of the developed molds. The error caused by concrete deflection under load or the error caused by repeated fabrication was about 0.5 mm. The shape error was within 3.5 mm. This small error proved greater accuracy compared to the existing technology.
Revised. [abstract] Many studies have been conducted for the accuracy of free-form concrete panel fabrication, but there still are errors in the process of fabrication. This study developed a connection technology of detachable shape part that can be applied to the existing multi-point Computer Numerical Control (CNC) to enhance the accuracy of fabrication. The detachable type can place a silicon plate on top of the rod without additional fixtures. The accuracy of the technology was verified by curvature test and free-form concrete panel fabrication test. Three curves were created to compare the discrepancies between the designed shapes and the fabricated shapes through qual-ity test. As a result, the detachable type decreased the error by up to 2 mm. The error of the mold curve was within 3 mm, which was the allowable error suggested by the current study. The error caused by concrete deflection under load or the error caused by repeated fabrication was about 0.5 mm. The shape error was within 3.5 mm. This small error proved greater accuracy compared to the existing technology.
Reviewer comments. Please, provide the standard test methods used for the experiments. The methodology of "Free-form concrete panel fabrication and quality test process" is unclear. Preparation of samples for testing and the results are debatable. What standards did the methodology and testing machine meet? There is no statistical analysis. You should comment on that.
Reply. There is no standard for this test. We calculated the difference between the design and the implemented panel as an error. We have specified this fact in the relevant paragraph.
Added. [line 360] Because there is no standard experimental method for measuring error of free-form concrete panel fabrication, the following method was proposed and the error was measured through this method.
Original. [figure 12] Free-form concrete panel fabrication and quality test process
Revised. [figure 12] Free-form concrete panel fabrication and quality test process of this study
Reviewer comments. Figure 10. Shape engineering and curve forming, (c) Calculating moving values of rods - there are many unnecessary details and small view.
Reply. We revised the figure (c) Calculating moving values of rods in figure 10 simply
Reviewer comments. The paper can benefit from a minor editorial work up to check up spelling and any grammatical issues. My main suggestion is to check thoroughly the text, regarding both the language and the information provided in Section 5. "Conclusion”. The conclusions can be improved by citing in bullet format the key finds and any issues that may have added to improving or affected the outcome of the results. The Conclusions should be completely rewritten to include more specific information.
Reply. We rewritten to rewritten conclusion to include more specific information as below.
Original. [conclusion] The current study developed a connection technology of shape part suitable for multi-point CNC, and it analyzed the limitations of the existing fixed type and developed the detachable type connection technology for improvement. The detachable type places the silicon plate on the rods without any fixtures. A silicon cap was placed at the end of each rod and the rods were elevated as engineered to place the silicon plate on top. Then, the joints revolved freely to create the curve. For verification, the existing fixed type and the new detachable type were applied to create curves and analyze the shape error. The detachable type’s shape error was smaller than that of the existing fixed type and the error reduced by up to 2 mm. This indicated that the shape was more accurate than the existing method. Panel fabrication test was conducted to test the errors that occur when the new technology was applied to fabricate the panels and the rigidity of the mold equipment. The error of the mold curve was within 3 mm, which was the allowable error suggested by the current study. Next, as a result of shape analysis after panel fabrication, the deflection by the load of concrete was about 0.5 mm. This was a minor error, manifesting that the detachable type suggested in the current study has excellent resistance against the load of concrete. The range of shape error caused by repeated fabrication was within 3-3.5 mm. There was about 0.5 mm of error, but it was a minor error, meaning that the rigidity of mold was also suitable for panel fabrication. The current study suggested a new technology to overcome the limitations of the existing technology and fabricated the panels to prove outstanding accuracy. Therefore, the technology would be able to fabricate high-quality panels. However, the shape error of the fabricated panels exceeded the allowable error suggested by the current study although it was very small. Therefore, additional studies would be required for the shape error to satisfy the allowable error in panel fabrication. Also, the current study can only fabricate panels of certain sizes and additional studies would be necessary to fabricate free-form concrete panels for actual structures and test the accuracy in order to apply the new technology to real life.
Revised. [] The current study developed a connection technology of shape part suitable for multi-point CNC, and it analyzed the limitations of the existing fixed type. This study developed the detachable type connection technology. The detachable type places the silicon plate on the rods without any fixtures. A silicon cap was placed at the end of each rod and the rods were elevated as engineered to place the silicon plate on top. Then, the joints revolved freely to create the curve surface. For verification of technology, the existing fixed type and the new detachable type were applied to create curves and analyze the shape error. Because there is no standard experimental method for measuring error of free-form concrete panel fabrication, the following method was proposed and the error was measured through this method. The detachable type’s shape error was smaller than that of the existing fixed type and the error reduced by up to 2 mm. This indicated that the shape was more accurate than the existing method. Panel fabrication test was conducted to test the errors that occur when the new technology was applied to fabricate the panels and the rigidity of the mold equipment. The error of the mold curve was within 3 mm, which was the allowable error suggested by the current study. Next, as a result of shape analysis after panel fabrication, the deflection by the load of concrete was about 0.5 mm. This was a minor error, manifesting that the detachable type suggested in the current study has excellent resistance against the load of concrete. The range of shape error caused by repeated fabrication was within 3-3.5 mm. There was about 0.5 mm of error, but it was a minor error, meaning that the rigidity of mold was also suitable for panel fabrication. The current study suggested a new technology to overcome the limitations of the existing technology and fabricated the panels to prove outstanding accuracy. Therefore, the technology would be able to fabricate high-quality panels. However, the shape error of the fabricated panels exceeded the allowable error suggested by the current study although it was very small. Therefore, additional studies would be required for the shape error to satisfy the allowable error in panel fabrication. Also, the current study can only fabricate panels of certain sizes and additional studies would be necessary to fabricate free-form concrete panels for actual structures and test the accuracy in order to apply the new technology to real life.
