Warp Prediction Algorithm for Wood Products Using Differential Characteristics

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Solution Overview

Problem

Current methods for evaluating the warp stability of wood products are inadequate, as they cannot accurately predict dimensional changes and warp properties in real-time production environments, leading to dissatisfaction among customers due to unpredictable shrinkage and moisture content variations.

Innovation Solution

Developing methods to measure and predict the warp profile of wood products using differential characteristics such as curvature, by converting measured warp profiles into differential characteristic profiles and creating prediction algorithms based on sensor data, allowing for real-time monitoring and classification of wood products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional visual grading methods are used to assess lumber quality, then grading is simple and fast, but dimensional stability and warp properties cannot be accurately predicted

Engineering Contradiction:
Improvewarp prediction accuracyVSAvoidgrading system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The lumber board is divided into multiple measurement sections along its length. Sensors measure different properties (moisture content, acoustic velocity, capacitance) at each section independently. These segmented measurements are then integrated to create a comprehensive warp prediction model, allowing accurate assessment without requiring complex single-point measurement systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Differential characteristics (first and second derivatives of warp profile) serve as intermediary parameters that link measurable properties (acoustic velocity, capacitance, moisture content) to the final warp prediction. These differential characteristics act as mediators that translate sensor data into meaningful dimensional stability assessments.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple sensor types are used to measure wood properties, then measurement accuracy improves, but system complexity and cost increase

Engineering Contradiction:
Improveproperty detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs multiple sensor types (acoustic velocity sensors, capacitance sensors, moisture content sensors) that each serve multiple functions. For example, acoustic velocity measurements provide both density information and structural integrity data. This multi-functionality reduces the need for separate specialized sensors, maintaining measurement precision while controlling system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system measures different physical parameters (acoustic velocity, capacitance, moisture content) that all correlate with wood properties affecting warp. By changing measurement parameters rather than using a single complex sensor, the system achieves comprehensive assessment through multiple simpler measurement modalities.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If comprehensive warp assessment is performed, then customer satisfaction improves, but processing time and complexity increase

Engineering Contradiction:
Improvewarp stability reliabilityVSAvoidgrading throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary measurements of multiple properties (moisture content, acoustic velocity, capacitance) and calculates differential characteristics during the grading process itself, rather than requiring separate subsequent testing. This preliminary action ensures comprehensive warp assessment is integrated into the production flow, maintaining reliability without significant productivity loss.

Inventive Principle:
Principle #10Preliminary action

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 accurate prediction and classification of warp stability, improving the estimation of dimensional stability and reducing customer dissatisfaction by providing precise quantification of wood product properties, even in varying moisture conditions.

Implementation Method 1

MOE can be estimated from the propagation of sound through wood

Methodology Applied
Scientific EffectAcoustic velocity propagation: Sound

Implementation Method 2

specific gravity can be estimated from the capacitance of wood

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentUS7630847B2Methods for predicting dimensional stability of a wood product based on differential characteristics
Publication Date: 2009.12.08 WEYERHAEUSER NR CO
  • US7630847B2 patent drawing
  • US7630847B2 patent drawing
  • US7630847B2 patent drawing

AI summary

Methods are provided for predicting warp of a wood product given its differential characteristics, such as, for example, curvature. The methods may involve measuring at least one original warp profile for each of one or more first wood products; measuring one or more inputs on the one or more first wood products; converting the warp profile, for each of the one or more first wood products, into a differential characteristic profile; developing a prediction algorithm based on the one or more inputs and the differential characteristic profile; measuring one or more inputs of the given wood product; inputting the one or more inputs of the given wood product into the prediction algorithm; and determining a differential characteristic profile for the given wood product based on the prediction algorithm.