Nonwoven Sheet Manufacturing Pressing Force Sequence
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Solution Overview
Problem
Nonwoven fabric manufacturing apparatuses that heat the web before pressing result in insufficient density and strength due to resin melting between fibers that are not sufficiently compressed, leading to a web form that cannot be broken and lacks sufficient density or strength.
Innovation Solution
A sheet manufacturing apparatus and method where a web is formed by depositing fibers and resin, then pressed without heating, followed by heating and pressing downstream, with a pressing force greater than the heating and pressing force to shorten fiber distances and prevent springback, ensuring high density and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the web is heated before pressing, then resin is melted and bound between fibers, but the fibers are not sufficiently compressed resulting in insufficient density and strength
Solution Approach 1:
The pressing operation is performed before heating to compress the fibers and reduce air gaps. This preliminary mechanical compression creates a dense structure that will later retain its form when heat is applied, solving the contradiction by establishing density before resin bonding occurs.
Solution Approach 2:
The manufacturing process is divided into two distinct stages: a pressing stage without heating to achieve fiber compression and density, followed by a heating stage to melt resin and bond fibers. This segmentation allows each process to optimize for its specific function without interfering with the other.
2Reliability
If the web is heated before pressing, then resin bonding occurs, but the web form is established in a state of insufficient density and cannot be broken
Solution Approach 1:
The web is pressed to achieve sufficient density and establish a breakable form before heating. This preliminary compression ensures that when resin is later melted and bonded, the web has already achieved the desired density and structural integrity, resolving the contradiction between form stability and density.
3Manufacturing precision
If pressing force is applied after heating, then resin is already bonded, but insufficient compression was achieved before bonding
Solution Approach 1:
Maximum pressing force is applied before heating to achieve the desired density and compression. This preliminary mechanical action ensures that fibers are sufficiently compressed and air gaps are reduced before resin bonding occurs, allowing subsequent heating to simply bond the fibers without compromising density or strength.
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 approach allows for the formation of sheets with high density and strength by pressing the web before heating, ensuring resin melts and fibers bond in a compressed state, thereby enhancing the web's structural integrity and reducing springback.
Implementation Method 1
a pressing unit that presses the web without heating the web... A distance between the fibers configuring the web is shortened by pressing
Implementation Method 2
a heating and pressing unit that heats and presses the web... resin is melted and the fibers are bonded
Implementation Method 3
a web forming unit that forms a web in which at least fiber and resin are deposited in the air
Data Source
AI summary
A sheet manufacturing apparatus includes a web forming unit that forms a web in which at least fiber and resin are deposited in the air; a pressing unit that presses the web; and a heating and pressing unit that heats and presses the web on a further downstream side than the pressing unit in a transport direction of the web, in which a pressing force of the pressing unit is greater than a pressing force of the heating and pressing unit.