Laser Scanner Shadow Edge Method for Online Roundness Measurement
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Solution Overview
Problem
Existing methods for determining the shape parameters of long products, particularly roundness, in rolling mills are limited by inaccuracies in measuring non-round profiles and the inability to perform online measurements, leading to flawed calculations and incomplete representation of the product's profile.
Innovation Solution
A method using at least two laser scanners with light-sensitive sensors to generate shadow edges, calculate tangents, and define a reference circle, allowing for the determination of shape parameters through contour simulation and sector alignment, enabling precise online measurement of long products, including round and irregular profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical roundness measuring devices are used to determine shape parameters of long products, then measurement precision can be achieved, but the measurement process must be carried out offline and cannot be performed on the production line
Solution Approach 1:
The patent replaces mechanical contact-based roundness measuring devices with a non-contact optical measurement system using laser scanners. The laser scanners project laser beams to create shadow edges on the long product, which are then processed to generate tangents and determine the reference circle and shape parameters. This substitution eliminates the need for mechanical contact and offline measurement, enabling continuous online measurement on the production line while maintaining measurement precision.
2Productivity
If multiple tangents are measured simultaneously to determine the profile of a local cross-section, then online measurement is possible, but mechanical measurement cannot capture the complete circumferential profile with unlimited points
Solution Approach 1:
The patent transitions from mechanical point-by-point measurement to optical field-based measurement by introducing laser scanners that project laser beams across the entire circumferential profile simultaneously. This creates shadow edges that contain information about all circumferential points at once, allowing the system to determine the complete profile in a single measurement instance rather than requiring sequential mechanical scanning.
Solution Approach 2:
The laser scanners create optical copies (shadow edges) of the long product's cross-sectional profile. These shadow edges are projected onto detection surfaces and processed to reconstruct the complete circumferential profile. The copying process allows simultaneous capture of all profile points without mechanical contact, enabling both online measurement capability and complete profile determination.
3Manufacturing precision
If calipers with support prisms are used to determine equal thickness errors, then different support angles can be recommended based on waviness, but the measurement does not reflect the true profile character of non-round products
Solution Approach 1:
The patent explicitly handles asymmetric and non-uniform profiles by generating multiple tangents at different angular positions around the long product's cross-section. The system calculates a reference circle and determines shape parameters based on deviations from this reference, capturing the true asymmetric profile character rather than forcing symmetric measurements that mask the actual profile variations.
Solution Approach 2:
The patent uses laser illumination to create visible shadow edges that represent the profile shape. The optical measurement system detects variations in the shadow edge positions and intensities, which correspond to different profile heights and curvatures. This optical approach provides visual and measurable information about the true profile character, including asymmetric features, without the limitations of mechanical contact measurement.
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 method provides accurate and comprehensive shape parameter determination, including out-of-roundness, by minimizing errors and capturing the true profile character of long products, even in production-line settings, and can be applied to various rolling processes.
Implementation Method 1
using a measuring device with at least two laser scanners, each of which has a light-sensitive sensor and a laser
Implementation Method 2
at least three shadow edges which are adjacent to the longitudinal product to be measured and surround the longitudinal product
Data Source
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AI summary
A method is provided for determining shape parameters of elongated products that are moved along the longitudinal direction thereof in rolling lines, in particular for determining the roundness of round profiles, wherein at least three shadow angles are generated and measured in a known method per se using a measurement device comprising at least two laser scanners, each of which comprises a light-sensitive sensor and a laser, said angles sitting against the elongated product to be measured and surrounding the elongated product, said shadow angles forming a polygon, wherein the corresponding tangents are calculated from said shadow angles. A contour is determined from the polygon. Contour segments are established on said contour. The desired shape parameters can be calculated from this data.