Rotary Foam Surface Shaping for Deep Vertical-Wall Troughs
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Solution Overview
Problem
Existing methods for cutting slabs of cellular polymer materials, such as polyurethane foam, struggle to produce deep cut portions with vertical side walls and flattened bottom surfaces, limiting the depth of cut to about 80% of the foam thickness and making it difficult to achieve such features using continuous cutting methods.
Innovation Solution
A method involving a die roller with raised portions and a pressure roller with complementary recesses, where the foam is compressed and extruded into these patterns, allowing a blade to cut away the extruded portions, resulting in a pad with raised portions separated by depressions having vertical side walls and planar bottom surfaces, with the raised portions being at least 50% of the pad's thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a smooth compression roller and a die roller with raised and recessed portions are used to compress foam, then the foam can be continuously shaped, but it is difficult to produce troughs with flattened bottom surfaces and the depth of cut is limited to the die roller pattern depth
Solution Approach 1:
Instead of using a die roller with raised portions that compress the foam and leaving recesses to be cut away, this patent inverts the approach by using a die roller with recesses that compress the foam while raised portions are extruded and cut away. This inversion allows the compressed foam to form troughs with flattened bottom surfaces corresponding to the die roller recesses, while the extruded raised portions are removed by cutting blades positioned tangentially to the die surface.
Solution Approach 2:
The patent positions cutting blades in a cutting plane that is substantially tangent to the cylindrical die surface, rather than parallel to the roller axes. This dimensional change in blade positioning allows the blades to effectively cut the extruded raised portions while the foam is still in its compressed state, enabling deeper cuts with vertical side walls that would not be achievable with conventional cutting arrangements.
2Shape
If the depth of cut is increased to produce deep cut portions up to 80% of foam thickness, then complex three-dimensional shapes can be formed, but the side walls become difficult to process and maintain verticality
Solution Approach 1:
The patent performs the cutting action while the foam is still in its compressed state within the nip between the die roller and pressure roller. By cutting the extruded raised portions before the foam fully expands, the process achieves deeper cuts with more vertical side walls. The compressed state provides better structural support for the deep cuts, and the tangential blade positioning allows precise removal of material to create vertical side walls that would be difficult to achieve after expansion.
3Shape
If conventional cutting methods are used, then the process is simpler, but the raised portions cannot achieve heights greater than about 50% of the pad thickness
Solution Approach 1:
The patent designs the die roller recesses and pressure roller raised portions to nest within each other at the nip point. The raised portions of the die roller are positioned to extrude through the foam, while the recesses in the pressure roller provide complementary shaping. This nested arrangement allows the foam to be compressed and shaped simultaneously, enabling the formation of raised portions that extend to at least 50% of the pad thickness while maintaining process efficiency.
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 enables the creation of foam parts with deep cut portions up to 80% of the foam thickness, featuring vertical side walls and planar bottom surfaces, improving the processing of foam parts with enhanced support and ventilation characteristics.
Implementation Method 1
Some portions of the cellular polymer material are compressed against said raised die portions to a reduced thickness and other portions of the cellular polymer material are extruded into said die depressions
Implementation Method 2
The compressed foam portions return to an uncompressed state after passing through the rollers
Data Source
AI summary
Apparatus and methods for cutting compressible cellular polymers such as polyurethane foam, are characterized by a first die roller and a pressure roller, wherein both rollers define raised portions separated by recesses or depressions, and the raised portions on the first die roller register with the recesses of the pressure roller at a nip formed between the rollers. Portions of the polymer material extruded into the spaces between the raised portions of the first die roller are cut away, such that the cut product conforms substantially to the surface geometry of the first die roller, and the depth of cut is greater than with prior rotary cutting methods.