Contoured Pleated Filter Element Cutting and Edge Sealing
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Solution Overview
Problem
Existing methods for producing pleated filter elements with precise contours face challenges due to dimensional instability and deformation issues, particularly when using rotating cutting knives, which limit the variety of shapes that can be achieved and result in undesired edge distortions.
Innovation Solution
A method and device utilizing a cutting die with a closed ring contour and an axial punching knife for precise cutting, combined with heat treatment to stabilize the edge seam, allowing for the production of non-rotationally symmetrical contours and reducing deformation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rotating cutting knives are used to cut out filter elements from pleated filter medium, then cutting can be performed, but dimensional instability and springback cause changes in shape and deviations in edge contour
Solution Approach 1:
The filter medium is pre-compressed between a counter-holder and a stamp with a surface structure adapted to the fold pattern before cutting. This preliminary compression stabilizes the pleated structure and prevents springback during and after cutting, thereby maintaining edge contour precision while enabling effective cutting operation.
2Productivity
If pleated filter medium is clamped and cut with rotating cutting knives, then filter elements can be produced, but tension builds up in the filter element leading to undesired deformations of the edge contour after removal
Solution Approach 1:
The filter medium is pre-compressed between a counter-holder and a stamp with a surface structure adapted to the fold pattern before cutting. This preliminary compression stabilizes the pleated structure and prevents springback during and after cutting, thereby maintaining edge contour precision while enabling effective cutting operation.
3Ease of manufacture
If rotating cutting knives are used, then cutting can be performed, but only rotationally symmetrical shapes can be produced
Solution Approach 1:
Instead of using a rotating cutting knife that moves around the filter element, the invention uses a stationary or linearly moving punching knife that moves through the compressed filter medium in a single direction. This inverted approach to cutting motion allows for non-rotationally symmetrical shapes and diverse contours while maintaining manufacturing simplicity.
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
Enables the production of filter elements with precise, varied contours without rotating cutting knives, minimizing edge distortions and enhancing the stability of the filter element's edge, thus facilitating more accurate and versatile filter element manufacturing.
Implementation Method 1
a punching knife is used as the cutting die, which is only moved axially to the clamped filter medium for trimming
Implementation Method 2
an edge seam of the cut filter element is melted and solidified under the action of heat while the filter element is clamped between the counter-holder and the stamp
Data Source
Figure 1~3
Figure 4
AI summary
The invention relates a method and device for producing a contoured pleated filter element, wherein a pleated filter medium with a pattern of folds is clamped between a counterholder and a punch precisely to its shape. The counterholder and punch each have a surface structure matched to the pattern of folds and a side edge which corresponds to a contour desired for the filter element to be produced. The clamped filter element is cut out of the filter medium along the side edge to the desired contour. The filter medium is a thermoplastic material. To form an edge, an edge seam of the cut filter element is melted under the influence of heat and hardened while the filter element is clamped between the counterholder and the punch.