Web Unevenness Due to Thermal Deformation in the Roll-to-Roll Manufacturing Process
Round 1
Reviewer 1 Report
Commentary - see appendix.
The topic of the article is interesting and current, and it is good that the authors are dealing with it.
Comments for author File: 
Comments.pdf
Author Response
Reviewer #1: Commentary – see appendix.
- Page 2, line 88-91 : Add some sentences
Response:
Thank you for your comment. We modified the above sentences as follows:
- Finite Element Analysis: Thermal – Structural Coupled Analysis
A thermal-structural coupling analysis was carried out using FEA. Considering the boundary conditions at the inlet of the dryer and external forces applied to the web, an FEM of the web near the inlet of the dryer was designed to understand the deformation of the web due to the convection and conduction heats from the dryer.
2.1. Finite Element Modeling
A polyethylene terephthalate (PET) film (CD-901, KOLON Inc., Korea) was used in this study. Table 1 presents the mechanical and thermal properties of the web, while the boundary conditions defined for the model are shown in Table. 2
- Table. 1 in the main text
Response: Thank you for your comment. We modified the “unit” column to fit format.
- Table. 2 in the main text
Response: Thank you for your comment. We added space between Table. 2 and the text.
- page 2, line 102: "Figures 1b and c" -> "Figures 1b and 1c"
- page 3, line 110: "web.[21]" -> "web. [21]"
- page 3, line 110: "was set from 30°C to 120°C " -> "was set from 30 °C to 120 °C "
- page 3, line 115: "where {} is the total strain " -> "Where {} is the total strain"
- page 4, line 134: "dryer at the 60 °C-drying temperature" -> "dryer at the 60 °C - drying temperature"
Response: Thank you for your comment. We have corrected the typo.
- Figure 2 : there is an overlap of panels after (a) and (b) by two (c)
Response: Thank you for your comment. We have modified panel (c) below panel (b) to panel (d)
- Figure 2 caption : space needed between values and unit
Response: Thank you for your comment. “(a) 30°C, (b) 60°C, (c) 90°C, and (d) 120°C.”-> “(a) 30 °C, (b) 60 °C, (c) 90 °C, and (d) 120 °C.”
- Table. 3 in the main text : space needed between values and unit
Response: Thank you for your comment. We added space between values and unit. Additionally, we added space between Table.3 and text
- Page 6, line 164-167 : Add some sentences
Response:
Thank you for your comment. We modified the above sentences as follows:
- Experiment
The YSZ electrolyte layer (572349-25G, Sigma-Aldrich Inc., USA) was coated by an industrial-scale R2R slot-die coating machine as shown in Figure 5. The YSZ satisfies the requirements of an electrolyte layer of SOFCs and solid oxide electrolyzer cells (SOECs) due to its advantages of high ion-conductivity and chemical stability [22–25].
3.1. Mechanical Properties of YSZ Coating Layer
Figure 5a shows the schematics of R2R slot die coating process and Figure 5b and c shows the enlarged image of the section near the inlet of the dryer.
- page 6, line 169: "coating process and Figure 5(b),(c)" -> "coating process and Figure 5b and c"
Response: Thank you for your comment. We have corrected the typo.
- Table. 4 in the main text
Response: Thank you for your comment. We added space between Table. 4 and the text.
-Figure 6 : unit of x-axis in panel (b) is confusing
Response: Thank you for your comment. Since the unit of strain is dimensionless, mm/mm was deleted to prevent confusion.
- Figure 8 caption : space needed between values and unit
Response: Thank you for your comment. “(a-c) 30°C, (d-f) 60°C, (g-i) 90°C, and (j-l) 120°C.”-> “(a-c) 30 °C, (d-f) 60 °C, (g-i) 90 °C, and (j-l) 120 °C.”
- page 10, line 214: "where ET represents" -> " Where ET represents "
Response: Thank you for your comment. We have corrected the typo.
- page 10, line 214-216 : Format of chemical formula
Response: Thank you for your comment. We have corrected the chemical formula and fitted the line spacing
Reviewer 2 Report
Dear editor, dear authors,
In their manuscript „Web Unevenness Due to Thermal Deformation in Roll-to-Roll Manufacturing Process“ the authors study, theoretically and experimentally, the formation of defects in a layer of yttria-sbailized zirconia (YSZ) which is created by coating process on a plastic (PET) web. The YSZ layer is a central component of solid oxide fuel cells, and proper process control here is essential for successfull fuel cell manufacturing on the large scale. It is argured that the dominating defect formation mechanism is related to the drying process subsequent to coating. Temperature raise in the drying oven gives rise to thermal expansion of the PET, which, in connection with mechanical tension, yields a complex in-plane, but also out-of-plane deformation pattern in the originally planar web.
Deformation patterns are the studied using a FEM simulation. Comparing the result to their experiments the authors show that it is well correlated well with the defect pattern in the layers which were examined using SEM techniques. This yields convincing evidence for correctness of their hypothesis and modeling.
The manuscript is written in a condensed and clear style. Literature citation is adequate. I consider the topic as fairly important, and it could address a broad readership. I found it particularly interesting and remarkable that the complex pattern formation phenomenon of the PET foil and the related layer defect creation has, in effect, a satisfactory explanation by a fairly simple, linear material model.
The manuscript appears fully suited for Applied Sciences, and I can warmly recommend it for publication.
The only point which I would like to suggest concerns the assumptions on the material properties of the PET foil used here. The deformation under stress and temperature change, eq. (1), is assumed to be fully reversible. In practice, however, using slit-extruded PET foils, if not annealed, a permanent deformation can sometimes be observed after a thermal cycle. Perhaps the authors could add a note on that problem, or whether this can be considered as not relevant here.
Author Response
Reviewer #2: The only point which I would like to suggest concerns the assumptions on the material properties of the PET foil used here. The deformation under stress and temperature change, eq. (1), is assumed to be fully reversible. In practice, however, using slit-extruded PET foils, if not annealed, a permanent deformation can sometimes be observed after a thermal cycle. Perhaps the authors could add a note on that problem, or whether this can be considered as not relevant here.
Response: Thank you for your comment. We have checked the assumptions of the eq. (1) and modified the above sentence as follows
Although there is a web where permanent deformation occurs after the thermal cycle, such as slit – extruded PET foils, permanent deformation after the thermal cycle is ignored because this study takes the correlation between thermal deformation inside and outside the dryer and coating performance into account.
