Rolling Mill Rod Length Control via Laser Integration

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Solution Overview

Problem

Current methods for determining the length of rolled rods in rolling mills are complex and inaccurate, leading to oversize sections that reduce productivity and efficiency.

Innovation Solution

A method utilizing a rear laser measurement device to detect the head end and speed of the rod, integrating the speed to determine the instantaneous length and providing cutting commands for precise sectioning, while accounting for thermal shrinkage and using laser measurement devices upstream and downstream of the oven to calculate the expected thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the predetermined length is determined to ensure minimum length requirements are met, then the reliability of section length is improved, but the productivity decreases due to increased oversize sections

Engineering Contradiction:
Improvesection length complianceVSAvoidrolling mill output
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces mechanical measurement methods with optical laser measurement technology. The laser measurement device non-contactly measures the actual length of the rod in real-time, providing precise data for cutting commands without the delays and inaccuracies of mechanical measurement systems, thus reducing oversize sections while maintaining length compliance

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback control system where the laser measurement device continuously monitors the actual rod length, and the control device uses this real-time information to adjust cutting commands. This closed-loop feedback enables dynamic optimization of section length, minimizing oversize portions while ensuring minimum length requirements are met, thereby improving both reliability and productivity

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If complex measurement and control methods are used to improve measurement precision, then the manufacturing precision is improved, but the device complexity increases

Engineering Contradiction:
Improverod length accuracyVSAvoidmeasurement and control system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from complex mechanical measurement systems and implements it through a dedicated laser measurement device. This separation allows the use of simple, direct laser measurement technology for length detection, avoiding the complexity of integrated mechanical measurement and control systems while achieving high manufacturing precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The laser measurement device serves multiple functions: it measures the actual length of the rod, detects the position of the head end, and provides data for both process control and quality verification. This multi-functionality reduces the need for separate measurement and control devices, simplifying the overall system while maintaining high precision

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

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 allows for highly accurate determination of rod length, reducing oversize sections and improving productivity by enabling precise cutting commands and adaptive length adjustments.

Implementation Method 1

detecting by means of a rear laser measurement device arranged downstream of the rolling mill the head end and the speed of the rod

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

a thermal shrinkage of the sections of the rod due to the difference between a finishing temperature and a normal temperature

Methodology Applied
Scientific EffectThermal shrinkage: Thermal Contraction

Implementation Method 3

a coefficient of thermal expansion is determined, and said coefficient of thermal expansion is taken into account when determining the expected thermal shrinkage of the sections of the rod

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3268142B1Method of operation of a rolling mill
Publication Date: 2019.11.20 PRIMETALS TECH GERMANY GMBH
  • EP3268142B1 patent drawingFigure 1
  • EP3268142B1 patent drawingFigure 2~4

AI summary

A billet (2) is rolled in the rolling mill to a rod (3), said rod (3) exiting the rolling mill with a finishing temperature (TE1). By means of a rear laser measurement device (8) arranged downstream of the rolling mill, the head end and the speed (v) of the rod (3) are detected. The detected speed (v) of the rod (3) is integrated. Thereby an instantaneous length (L) of the rod (3) is determined. In dependency on the determined instantaneous length (L) of the rod (3) cutting commands (S) to a rear shears (5) arranged downstream of the rolling mill are provided for cutting the rod (3) in sections (6) of predetermined length (L0). Said sections (6) of the rod (3) are cooled down in a cooling bed (7).