Sheet Manufacturing Apparatus Deformation Control
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Solution Overview
Problem
Existing sheet manufacturing apparatuses face challenges 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 from fibers and a forming unit with a first roller for heating, a second roller for nipping, a winding roller, and pressing rollers to control the sheet's moisture content and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the sheet is dried downstream of the heating and pressing rollers, then the moisture content is reduced, but the sheet contracts and deforms (wrinkles occur)
Solution Approach 1:
The sheet is wound around the heating roller before drying completes, and pressing rollers apply pressure in advance to prevent deformation. This preliminary pressing action occurs while the sheet is still warm and pliable, allowing the sheet to maintain its shape even as moisture is removed downstream
Solution Approach 2:
The pressing rollers apply a counteracting force to the natural contraction that occurs during drying. By pressing the sheet against the heating roller from the opposite side of the drying force, the system prevents wrinkles and deformation before they can fully develop
2Productivity
If the sheet is heated and pressed continuously, then productivity is improved, but sheet deformation increases due to contraction
Solution Approach 1:
The continuous heating and pressing process is segmented into discrete zones: a heating/pressing section with the first and second rollers, followed by a winding section with the winding roller and pressing rollers. This segmentation allows different sections to perform specialized functions - continuous processing in the first section and deformation prevention in the second section
Solution Approach 2:
The sheet is transitioned from a flat transportation state to a wound configuration around the heating roller. This dimensional change allows the pressing rollers to apply force effectively across the sheet surface and maintains the sheet in a controlled state during the drying process, preventing deformation while maintaining continuous production
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 allows for the production of sheets with reduced deformation and improved transportation stability by ensuring the sheet reaches an equilibrium moisture content, thereby minimizing wrinkles and transportation failures.
Implementation Method 1
a first roller configured to heat the web and the sheet
Implementation Method 2
a forming unit configured to press and heat the web to form the web into a sheet
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A sheet manufacturing apparatus includes: a deposition unit configured to deposit a material containing fibers to form a web; a humidification unit configured to moisten the web; a first roller configured to heat and dry the moistened web; a winding roller configured to wind a sheet around the first roller; and a pressing roller configured to press the sheet against the first roller.