Composite Wood Mat Preheating to Reduce Bowing
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Solution Overview
Problem
Conventional methods for manufacturing composite wood products, such as parallel strand lumber, result in bowing and dimensional instability due to manufacturing stresses, which are not effectively addressed by existing solutions that either require expensive press retrofits or reduce production throughput.
Innovation Solution
A method involving a continuous movement mechanism, side preheat assembly, and press assembly that adjusts temperature across the width of the mat before compression, using energy generators to apply heat to the sides of the mat, thereby reducing bowing without affecting production speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pressing methods are used to manufacture composite wood products, then production throughput is maintained, but bowing and dimensional instability occur due to manufacturing stresses
Solution Approach 1:
The patent applies preliminary heating to the mat before pressing to reduce manufacturing stresses that cause bowing. By pre-heating the mat to a specific temperature range (200-400°F) before compression, the wood elements become more pliable and less prone to stress-induced deformation during and after pressing, thereby reducing bowing without requiring slower production speeds
Solution Approach 2:
The patent changes the temperature parameter of the mat before pressing by applying heat energy through various methods (convection ovens, radiant heaters, microwave energy). This parameter change makes the wood elements more compliant during compression, allowing for reduced bowing while maintaining normal production throughput rates
2Manufacturing precision
If line speed is reduced to mitigate bowing, then bowing effects are reduced to some extent, but significant financial losses occur due to reduced production volume
Solution Approach 1:
Instead of reducing line speed, the patent applies preliminary heating to the mat before pressing. This preliminary action reduces the stiffness of wood elements, making them more compliant during compression and less prone to bowing, while allowing the pressing operation to maintain normal production speeds and volumes
Solution Approach 2:
The patent changes the temperature parameter of the wood elements before pressing, transforming them from a stiff, stress-prone state to a more pliable state that resists bowing. This parameter change allows normal production speeds to be maintained while achieving reduced bowing effects
3Manufacturing precision
If press infeed is reshaped with larger radius to reduce bowing, then bowing effects are mitigated, but retrofitting costs are extremely expensive and not feasible in some facilities
Solution Approach 1:
The patent applies preliminary heating to the mat before pressing, which reduces the stiffness of wood elements and makes them more compliant during compression. This approach reduces bowing without requiring expensive press retrofitting, making it accessible to facilities with space constraints or limited budgets
Solution Approach 2:
The patent replaces the mechanical solution of reshaping the press infeed with a thermal solution. Instead of modifying the mechanical pressing system, heat energy is applied to change the physical state of the wood elements, making them more compliant and less prone to bowing without requiring expensive mechanical modifications
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 effectively reduces bowing in composite wood products by preheating specific areas of the mat before compression, leading to more stable and straight beams with minimal deflection, maintaining stability over time.
Implementation Method 1
the temperature across the width W of the mat is adjusted... using energy generators to apply heat to the sides of the mat
Implementation Method 2
The mat is then compressed into a billet having a final thickness T2
Data Source
AI summary
The present disclosure includes systems and methods for manufacturing a composite wood product. In some embodiments, the method includes the steps of forming a mat from a plurality of wood elements and an adhesive, the mat having a width W measured substantially perpendicular to a longitudinal axis of the mat and an initial thickness T1. The mat is then moved in a machine direction, the machine direction being substantially parallel to the longitudinal axis and the temperature across the width W of the mat is adjusted. The mat is then compressed into a billet having a final thickness T2. In some embodiments, the system includes a continuous movement mechanism, a side preheat assembly, and a press assembly.