Colorant Application for Hit or Miss Defect Detection in Wood Processing
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Solution Overview
Problem
Current methods for detecting hit or miss defects in wood surfaces during the manufacturing of laminated hardwood floors are inefficient, leading to missed detections or false positives, which result in subpar product quality and increased waste due to manual labor costs and human errors.
Innovation Solution
Applying a colorant, such as red, green, or blue, to the wood surfaces before the sanding or planing process, allowing a color camera in the scanner to easily identify and remove colored areas indicating defects, thereby enhancing defect detection accuracy without increasing labor costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual defect detection and removal is used, then labor flexibility is maintained, but detection accuracy decreases and human errors increase
Solution Approach 1:
The patent applies colorant to the wood surface before scanning. The color changes the optical properties of the wood, making defects detectable by the color camera through color differentiation. This simple visual enhancement enables automated detection without complex sensing systems.
Solution Approach 2:
The colorant acts as an intermediary substance between the wood surface and the detection system. It mediates the interaction by creating a visual contrast that the camera can detect, translating physical surface variations into detectable color signals.
2Productivity
If automated scanning and cutting is implemented, then productivity increases, but initial investment and system complexity increase
Solution Approach 1:
By using colorant and color camera detection, the system achieves reliable automated defect identification. This enables the automated saw to accurately locate and remove defects, increasing productivity while keeping the detection system relatively simple and cost-effective.
3Productivity
If colorant is applied to wood surfaces, then defect detection efficiency increases, but additional processing step and material cost are added
Solution Approach 1:
The colorant is applied in advance before the wood enters the scanning system. This preliminary action prepares the wood surface with enhanced visual properties, allowing the color camera to detect defects efficiently during the scanning process without requiring additional detection equipment.
4Reliability
If conventional scanning without colorant is used, then process simplicity is maintained, but detection reliability decreases leading to missed defects
Solution Approach 1:
The colorant creates distinct color variations on the wood surface that correspond to defects. The color camera detects these color changes, enabling reliable identification of defects that would otherwise be invisible or indistinguishable, thereby reducing missed detections and wood waste.
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 coloration technique significantly increases the detection efficiency of hit or miss defects, reduces waste, and improves the quality of the finished product by accurately identifying and removing defects, while also extending the lifespan of sandpaper or planer knives and ensuring the economic viability of automated systems.
Implementation Method 1
The remaining coloured area will be detected more efficiently by a color camera used in the scanner equipment
Data Source
AI summary
In a wood processing plant, planks are typically split into strips and then passed through an automated cross-cutting saw station to remove defects such as knots, cracks or flash. One defect which also occurs is the hit and miss defect caused by a planer and/or a sander. In order to improve the performance of the cross-cutting saw station, color is applied to the wood prior to being planed and sanded. The cross-cutting saw station is then modified to optically inspect the wood for the presence of color, indicating a hit and miss defect, and to remove the portions of the wood containing color.