3D Nonwoven Fiber Deposition With Suction-Stabilized Base Layer
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Solution Overview
Problem
Existing production methods for three-dimensional non-woven fiber mats with variable thickness and surface mass are complex, require delicate handling, and result in products with poor stress resistance and non-homogeneous structures.
Innovation Solution
A production installation that deposits a mixture of unbonded fibers on a perforated conveyor belt, using suction to maintain the base layer and additional fiber nozzles to form a preformed 3D layer, which is then consolidated in an oven, with controlled conveyor and nozzle movements to achieve a final 3D sheet with variable thickness and surface mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple nozzles covering the entire width are used to deposit fibers onto a conveyor belt, then large parts can be produced, but the parts do not exhibit good resistance to stress
Solution Approach 1:
The fiber deposition process is segmented into multiple passes, with a single nozzle depositing fibers sequentially rather than attempting to cover the entire width in one pass. This segmentation allows for better fiber interlocking and structural integrity across the large surface area.
Solution Approach 2:
A base layer of fibers is deposited first and partially consolidated before additional fiber layers are added. This preliminary action creates a stable foundation that improves overall stress resistance of the large part.
2Strength
If layers of fibers with binding fibers or particles are molded and heated in an oven, then the fibers are consolidated with sufficient cohesion, but the molding systems are complex to build and operate
Solution Approach 1:
The complex molding system is replaced by extracting only the essential consolidation function - heating the fiber layers in an oven. The binding fibers are activated through thermal treatment alone, eliminating the need for complicated molding mechanisms.
Solution Approach 2:
Mechanical molding systems are replaced with a thermal consolidation process. The oven-based heating system substitutes for complex mechanical pressing and molding equipment, simplifying the overall system while achieving sufficient fiber cohesion.
3Ease of manufacture
If rotary mold systems are used for production, then molding can be performed, but the systems are poorly suited to the production of large parts
Solution Approach 1:
The production approach transitions from three-dimensional rotary mold systems to a two-dimensional conveyor belt system with overhead fiber deposition. This dimensional change enables the production of large-area parts that cannot be accommodated by rotary molds.
Solution Approach 2:
Instead of using a rotary mold to form the part from the inside out, the invention inverts the approach by depositing fibers onto a flat conveyor belt and consolidating them in place. This reversed methodology is better suited for large part production.
4Shape
If unconsolidated fibers are demolded and handled, then the molded shape can be achieved, but the handling is delicate until consolidation occurs
Solution Approach 1:
The fiber layers are deposited and partially consolidated on the conveyor belt before handling is required. This preliminary consolidation action strengthens the fiber structure, making subsequent handling easier while maintaining the desired shape.
Solution Approach 2:
The conveyor belt serves as an intermediary support that maintains the fiber layer shape during the transition from deposition to final consolidation. This intermediary support eliminates the need for delicate demolding operations.
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 method simplifies production, ensures homogeneous and stable 3D products with improved stress resistance by maintaining fiber shape and structure integrity during consolidation.
Implementation Method 1
suction means are provided, arranged so as to draw the air contained in the base layer to maintain it on the conveyor belt at the level of the supply zone
Implementation Method 2
at least one nozzle supplies the additional fibers by projection or injection by an air stream
Implementation Method 3
The preformed 3D layer is then conveyed into a consolidation element to consolidate the preformed 3D layer into the final 3D sheet
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a facility for producing a 3D fabric of nonwoven fibres, in particular made of felt, comprising a device (8) for depositing a mixture of fibres that are substantially not bonded together, in the form of a base layer (5), on an air-permeable, in particular perforated, conveyor belt. The base layer is conveyed to a zone (2), referred to as the supply zone, that is arranged facing at least one nozzle (3) for supplying additional fibres. The at least one fibre supply nozzle deposits additional fibres on the base layer in order to form, in at least one region of the base layer, at least one additional layer (6) in order thereby to obtain a three-dimensional or 3D preformed layer having a thickness and/or a mass per unit area that can be spatially varied. The 3D preformed layer is subsequently conveyed into a consolidation element (7) to consolidate the 3D preformed layer into the finished 3D fabric having a thickness and/or mass per unit area that can be spatially varied. The facility is characterised in that suction means are provided and are arranged so as to suck the air contained in the base layer in order to hold said base layer on the conveyor belt in the supply zone, and the at least one nozzle (3) is an injection nozzle that supplies the additional fibres by spraying or injection via a stream of air.