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1. Friction isolated rotary system for high-precision roll-to-roll manufacturing

   https://doi.org/10.1016/j.precisioneng.2020.12.018  

   Kang, Dongwoo ; Dong, Xin ; Kim, Hyunchang ; Park, Pyungwon ; Okwudire, Chinedum E. ( March 2021 , Precision Engineering)

   null (Ed.)
2. Spatial-Terminal Iterative Learning Control for Registration Error Elimination in High-Precision Roll-to-Roll Printing Systems

   https://doi.org/10.1115/MSEC2023-106259  

   Wang, Zifeng ; Jin, Xiaoning ( June 2023 , American Society of Mechanical Engineers)

   Roll-to-roll (R2R) printing techniques are promising for high-volume continuous production of substrate-based electronic products, as opposed to the sheet-to-sheet approach suited for low-volume work. However, one of the major challenges in R2R flexible electronics printing is achieving tight alignment tolerances, as specified by the device resolution (usually at micrometer level), for multi-layer printed electronics. The alignment of the printed patterns in different layers, known as registration, is critical to product quality. Registration errors are essentially accumulated positional or dimensional deviations caused by un-desired variations in web tensions and web speeds. Conventional registration control methods rely on model-based feedback controllers, such as PID control, to regulate the web tension and the web speed. However, those methods can not guarantee that the registration error always converges to zero due to lagging problems. In this paper, we propose a Spatial-Terminal Iterative Learning Control (STILC) method combined with PID control to enable the registration error to converge to zero iteratively, which achieves unprecedented control in the creation, integration and manipulation of multi-layer microstructures in R2R processes. We simulate the registration error generation and accumulation caused by axis mismatch between roller and motor that commonly exists in R2R systems. We show that the STILC-PID hybrid control method can eliminate the registration error completely after a reasonable number of iterations. We also compare the performances of STILC with a constant-value basis and a cosine-form basis. The results show that the control model with a cosine-form basis provides a faster convergence speed for R2R registration error elimination.

    

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3. Development of high-performance roll-to-roll-coated gas-diffusion-electrode-based fuel cells

   https://doi.org/10.1016/j.jpowsour.2021.230039  

   Mauger, Scott A. ; Wang, Min ; Cetinbas, Firat C. ; Dzara, Michael J. ; Park, Jaehyung ; Myers, Deborah J. ; Ahluwalia, Rajesh K. ; Pylypenko, Svitlana ; Hu, Leiming ; Litster, Shawn ; et al ( September 2021 , Journal of Power Sources)

   null (Ed.)
4. Spatial-Terminal Iterative Learning Control for Registration Error Elimination in High-Precision Roll-to-Roll Printing Systems

   Zifeng Wang, Xiaoning Jin ( September 2023 , Proceedings of the ASME 2023 18th International Manufacturing Science and Engineering Conference)

   Roll-to-roll (R2R) printing techniques are promising for high-volume continuous production of substrate-based electronic products, as opposed to the sheet-to-sheet approach suited for low-volume work. However, one of the major challenges in R2R flexible electronics printing is achieving tight alignment tolerances, as specified by the device resolution (usually at micrometer level), for multi-layer printed electronics. The alignment of the printed patterns in different layers, known as registration, is critical to product quality. Registration errors are essentially accumulated positional or dimensional deviations caused by un-desired variations in web tensions and web speeds. Conventional registration control methods rely on model-based feedback controllers, such as PID control, to regulate the web tension and the web speed. However, those methods can not guarantee that the registration error always converges to zero due to lagging problems. In this paper, we propose a Spatial-Terminal Iterative Learning Control (STILC) method combined with PID control to enable the registration error to converge to zero iteratively, which achieves unprecedented control in the creation, integration and manipulation of multi-layer microstructures in R2R processes. We simulate the registration error generation and accumulation caused by axis mismatch between roller and motor that commonly exists in R2R systems. We show that the STILC-PID hybrid control method can eliminate the registration error completely after a reasonable number of iterations. We also compare the performances of STILC with a constant-value basis and a cosine-form basis. The results show that the control model with a cosine-form basis provides a faster convergence speed for R2R registration error elimination. 

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5. Roll-to-roll continuous carbon nanotube sheets with high electrical conductivity

   https://doi.org/10.1039/C8RA01212A  

   Zhang, Songlin ; Leonhardt, Branden E. ; Nguyen, Nam ; Oluwalowo, Abiodun ; Jolowsky, Claire ; Hao, Ayou ; Liang, Richard ; Park, Jin Gyu ( January 2018 , RSC Advances)

   Highly electrically conductive, roll-to-roll continuous buckypaper (CBP) with stable performance was achieved by chemical doping and polymer coating (PEDOT:PSS).

    

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