Two-Stage Pressing Fibrous Preforms Cycle Time
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Solution Overview
Problem
Existing methods for producing products from fibrous materials face challenges in achieving complex geometries, reducing cycle time, and improving barrier properties, while also being limited by the need for moving form surfaces and high manufacturing costs.
Innovation Solution
A two-stage pressing method is employed, where a preform with a high moisture content is first pressed in a first pressing device with simultaneous heat input, followed by a second pressing in a second device with different temperature and pressure conditions, allowing for reduced cycle time and improved product geometry and barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single hot pressing step is used to reduce moisture content from 60% to 1-10%, then the moisture removal is achieved, but the cycle time becomes long and complex geometries cannot be produced
Solution Approach 1:
The hot pressing process is divided into two separate pressing devices: a first pressing device that performs initial pressing at a first temperature to remove excess moisture, and a second pressing device that performs final pressing at a second temperature to achieve the target moisture content of 1-10% and form complex geometries. This segmentation allows each device to be optimized for its specific function, reducing overall cycle time while enabling complex geometry production.
2Adaptability or versatility
If moving form surfaces are used in hot press tools to produce complex geometries, then geometry flexibility is improved, but device complexity and cost increase
Solution Approach 1:
The forming process is segmented between two pressing devices with different temperature settings. The first pressing device handles initial shaping, and the second pressing device handles final geometry formation. This allows complex geometries to be achieved through process segmentation rather than requiring complex moving form surfaces in a single device.
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
The two-stage pressing method significantly reduces cycle time, enables the production of products with complex geometries, and enhances barrier properties by controlling water discharge and fiber bonding, thus overcoming the limitations of prior art.
Implementation Method 1
first pressing of the preform with simultaneous heat input in a first pressing device
Implementation Method 2
The steam produced during hot pressing is suctioned off during the hot pressing via openings in the cavities and channels in the hot press tool
Implementation Method 3
at least a second pressing of the preform previously pre-pressed in the first pressing device with simultaneous heat input in a second pressing device
Implementation Method 4
the temperature introduced during the first pressing in the first pressing device and the temperature introduced during the at least one second pressing in the second pressing device are different
Implementation Method 5
The steam produced during hot pressing is suctioned off during the hot pressing via openings in the cavities and channels in the hot press tool
Data Source
AI summary
A method for forming products from fibrous material and a forming device for forming products from a fibrous material are described, where a multi-stage pressing of preforms made of fibrous material is carried out in order to improve the properties of products manufactured therefrom and to have a significant influence on the production time.