Veneer Compression Gap and Felt Assembly for Quality Control
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Solution Overview
Problem
The high compression forces and long treatment times required in assembling wood veneer sheets for panel structures result in reduced panel thickness and variations in veneer roughness and thickness, leading to inefficiencies and quality issues in plywood production.
Innovation Solution
A method and apparatus using an adjustable compression gap with press elements and an endless felt assembly to improve veneer quality, reducing surface roughness and moisture uniformity, allowing for lower compression pressures and reduced thickness deviation, and enabling densification and efficient drying processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high compression force is applied during panel structure gluing process, then veneer sheets can be assembled together, but the final thickness of the panel structure is reduced by about 8%
Solution Approach 1:
The invention applies preliminary compression treatment to the veneer sheets before the actual gluing process. By pre-compressing the veneers to a controlled degree (reducing thickness by 2-5% rather than 8%), the sheets are prepared to require lower compression forces during assembly, thereby preserving more of the original thickness in the final panel while still achieving proper bonding.
Solution Approach 2:
The invention changes the compression pressure parameter during different stages of processing. Instead of applying maximum compression throughout, the system uses moderate compression (2-5% thickness reduction) during preliminary treatment and then lower compression during the gluing process, optimizing both thickness preservation and assembly strength.
2Strength
If high compression force is applied during gluing process, then veneer sheets can be bonded together, but the treatment time becomes quite long (15 to 45 minutes)
Solution Approach 1:
By pre-compressing the veneer sheets to a controlled degree before gluing, the invention prepares the surfaces to require lower compression forces during the actual bonding process. This preliminary preparation reduces the time needed for the gluing operation itself, as the pre-compressed veneers bond more quickly and efficiently under reduced pressure conditions.
Solution Approach 2:
The invention changes the compression pressure parameter from high initial values to lower sustained values. By using moderate compression (2-5% thickness reduction) during preliminary treatment and then switching to lower compression during gluing, the system achieves proper bonding in shorter time (reducing from 15-45 minutes to a more efficient duration).
3Quantity of substance
If veneers are dried by traditional hot air drying, then moisture content is reduced, but thickness deviation occurs and surface roughness varies
Solution Approach 1:
The invention replaces traditional hot air drying with a mechanical compression-drying system. By applying controlled compression forces through rollers while the veneer passes through a drying chamber, the system mechanically removes moisture from the veneer surfaces and internal structure, achieving more uniform moisture distribution and reduced thickness deviation compared to conventional thermal drying.
Solution Approach 2:
The invention changes the drying mechanism from thermal (hot air) to mechanical-combined (compression + controlled drying). By controlling the compression pressure and drying conditions simultaneously, the system achieves superior moisture uniformity and thickness consistency while reducing surface roughness variations that occur with traditional hot air drying.
4Shape
If veneers are subjected to compression treatment, then surface roughness is improved, but the compression pressure must be optimized to avoid excessive compression
Solution Approach 1:
The invention optimizes the compression pressure parameter to a specific range (2-5% thickness reduction) that is sufficient to improve surface quality and reduce roughness without causing excessive compression. By controlling the pressure within this optimal range, the system achieves smooth veneer surfaces suitable for gluing and finishing while avoiding the damage and thickness loss associated with higher compression forces.
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 enhances veneer quality by reducing adhesive requirements, minimizing sanding needs, and optimizing drying processes, resulting in energy savings and improved product consistency, enabling the use of previously difficult-to-process wood species and reducing moisture and thickness deviations.
Implementation Method 1
veneers are conveyed through a compression gap made up by two press elements, the gauge of said gap being adjustable... both faces of the veneer are brought to a compression contact with the felt
Implementation Method 2
the applied pressure must be optimized individually in each case for optimal dewatering, yet without compressing the veneer too much... The regulation of compression can be used for influencing the degree of densification
Data Source
AI summary
A method and apparatus for improving of wood veneer quality is provided. In the method, veneers are conveyed through a compression gap made up by two press elements, the gauge of said gap being adjustable. The method comprises the use of an endless felt assembly, which is adapted to circle around at least one of the press elements and which passes through the compression gap in such a way that at least one face of the veneer is brought against the felt assembly in said compression gap.