Strip Flatness Measurement Using Lateral Projection
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Solution Overview
Problem
Existing methods for determining the flatness of moving strip material are limited by high strip tensions and are prone to measurement inaccuracies due to ambient lighting, making them unsuitable for industrial processes like rolling mills.
Innovation Solution
A method and device that project a projection pattern onto the strip material at a lateral angle between 1° and 45°, allowing for high-accuracy flatness determination even under high tensile forces, using projection-generating optics and a camera to capture the pattern, which reduces the influence of reflections and enables quick detection of deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light projection is performed at a small angle to the strip surface, then measurement accuracy is improved, but the influence of ambient lighting and reflections increases
Solution Approach 1:
The patent applies asymmetry by positioning the projection device at a lateral offset from the strip median plane, creating an asymmetric projection angle between 5° and 45° relative to the strip surface. This asymmetric configuration optimizes the balance between measurement sensitivity (improved by smaller angles) and reflection/ambient light interference (reduced by larger angles), resolving the technical contradiction between measurement precision and harmful environmental factors.
2Adaptability or versatility
If measurement is performed under high strip tension, then industrial applicability is improved, but measurement accuracy deteriorates due to strip deformation
Solution Approach 1:
The patent implements dynamics by enabling real-time flatness measurement during high-tension strip transport at industrial speeds. The measurement system dynamically adapts to the moving, tensioned strip material, capturing flatness data in situ without requiring the strip to be stationary or low-tension, thus maintaining both industrial applicability and measurement accuracy through dynamic measurement capability.
3Object-affected harmful factors
If lateral projection angle is increased, then reflection influence is reduced, but measurement sensitivity decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the projection angle parameter within the specific range of 5° to 45° relative to the strip surface. This parameter optimization balances two opposing requirements: smaller angles provide higher measurement sensitivity while larger angles reduce reflection interference. The selected angular range represents the optimal compromise point where both measurement sensitivity and reflection reduction are adequately achieved.
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 achieves high determination accuracy for strip material flatness in high-tension processes, allowing for timely correction of imperfections and improved processing results, suitable for industrial plants like rolling mills with tensile forces up to 100 N/mm2.
Implementation Method 1
a first source (401, 402, 403, 404) projects a first interference pattern (501, 502, 503, 504) onto the first surface (6) and a second source (401, 402, 403, 404) projects a second interference pattern (501, 502, 503, 504) onto the second surface (6)
Implementation Method 2
The at least one projection pattern is projected onto the surface of the strip material in the form of a projection grating
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a method and a device for ascertaining the flatness of transported strip material, having the steps of: moving the strip material (3) through a strip machining device, wherein a tensile force (Fx) of at least 10 N/mm2 is applied to the strip material (3); generating at least one projection pattern (5, 5') in the shape of a projection grid on the surface (6) of the strip material (3) by means of a projection-producing optical system (4, 4'), said projection pattern (5, 5') being projected onto the surface (6) of the strip material (3) from a position (P) which is laterally offset to the central plane (M) of the strip material (3), such that a projection angle (a) formed between the surface (6) of the strip material (3) and a projection beam (9) equals between 1° and 45°; and detecting the projection pattern (5, 5') by means of a camera (7), said camera (7) being arranged on a transverse plane (E) above the strip material (3) when viewed in the movement direction (X).