Sheet Manufacturing Apparatus Pressing Roller Position Control
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Solution Overview
Problem
Existing sheet manufacturing apparatuses face issues with sheet deformation, such as wrinkles, due to contraction of the sheet as it dries downstream of the heating and pressing rollers.
Innovation Solution
The apparatus includes a deposition unit for forming a web, a forming unit with heated rollers and a pressing mechanism to press and heat the web into a sheet, and a control unit that adjusts the position of the pressing rollers based on the temperature, rotation state, and position of the leading end of the sheet to minimize deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sheet is dried downstream of the heating and pressing rollers, then the sheet is deformed with wrinkles, but continuous transportation is maintained
Solution Approach 1:
The pressing roller is positioned to press the sheet against the heating roller before the sheet enters the drying zone downstream. This preliminary pressing action prevents deformation from occurring in the drying zone by maintaining sheet flatness in advance, thereby resolving the contradiction between continuous production and sheet flatness.
Solution Approach 2:
The pressing roller acts as an intermediary mechanism between the heating/pressing zone and the drying zone. By introducing this intermediate pressing action, the sheet is maintained in a controlled state that prevents wrinkle formation during the transition to the drying zone, enabling both continuous production and flatness maintenance.
2Device complexity
If the pressing roller position is fixed, then the structure is simple, but the sheet leading end causes transportation failures
Solution Approach 1:
The pressing roller is made movable along the sheet width direction rather than being fixed. This dynamic positioning capability allows the pressing roller to adapt to the sheet leading end position, preventing transportation failures while maintaining relatively simple device structure through linear motion adjustment.
Solution Approach 2:
The position parameter of the pressing roller is made variable to accommodate changes in sheet leading end position. By changing the pressing roller's position parameter dynamically, the system maintains reliable sheet transportation without requiring complex structural modifications.
3Manufacturing precision
If the pressing roller presses the sheet against the heating roller, then sheet deformation is reduced, but the pressing roller must be precisely positioned
Solution Approach 1:
A detection device monitors the position of the sheet leading end and provides feedback to the control device. The control device uses this feedback information to automatically adjust the pressing roller position, simplifying the positioning control task while maintaining high sheet flatness. The feedback loop eliminates the need for complex manual positioning systems.
Solution Approach 2:
The system uses the sheet's own leading end position information to automatically control the pressing roller positioning. The detection device and control device work together to make the system self-regulating, where the sheet itself provides the reference signal for positioning adjustment, reducing the complexity of external control mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the occurrence of deformation, such as wrinkles, and transportation failures of the sheet, ensuring a smoother and more stable sheet production process.
Implementation Method 1
a first roller configured to heat the web and the sheet
Implementation Method 2
a pressing roller configured to press the sheet wound around the first roller against the first roller
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of manufacturing a sheet, includes: moistening a web formed by depositing fibers; transporting the web downstream with the web pressed against a first roller by a pressing roller; after a transportation roller located downstream of the first roller nips the web, stretching the web with the pressing roller away from the first roller and the web; and drying the moistened web by heating the first roller, to manufacture a sheet.