Three-Roller Mill Pass Measurement for Accurate Major Semi-Axis
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Solution Overview
Problem
The existing three-roller reducing mill lacks a method to accurately measure the major semi-axis after processing, leading to errors in pass size, resulting in defects like black threads and internal ellipse defects in steel pipes, affecting the surface quality and accuracy of the outer diameter.
Innovation Solution
A method for rapidly measuring the major semi-axis of the three-roller reducing mill using a numerical control lathe, elliptical arcs, and geometric calculations to determine the correct processing size, ensuring the accuracy of the major semi-axis measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pass template is made to measure the pass size (major and minor semi-axis), then the measurement capability is improved, but the cost increases significantly
Solution Approach 1:
The patent uses a three-point internal micrometer to measure the minor semi-axis and calculates the major semi-axis through geometric relationships rather than creating a physical pass template. This copying approach measures the actual pass dimensions and uses mathematical models to derive the major semi-axis, avoiding the high cost of manufacturing custom templates while maintaining measurement accuracy
Solution Approach 2:
The patent replaces the mechanical pass template system with a combination of mechanical measurement (three-point internal micrometer) and mathematical calculation. By using the elliptical arc geometry and focal point relationships, the system substitutes physical templates with computational geometry, reducing manufacturing costs while enabling major semi-axis measurement
2Device complexity
If the major semi-axis cannot be measured, then the device complexity is reduced, but the manufacturing precision of the roller pass deteriorates
Solution Approach 1:
The patent introduces the three-point internal micrometer as an intermediary measurement tool that can access the roller pass geometry. By measuring the minor semi-axis and using the known elliptical arc parameters (focal point position, 120° included angle), the system indirectly determines the major semi-axis through geometric calculation, maintaining manufacturing precision without requiring direct major semi-axis measurement devices
Solution Approach 2:
The patent changes the measurement approach from directly measuring the major semi-axis to measuring the minor semi-axis and calculating the major semi-axis through parameter relationships. By utilizing the elliptical arc equation and the fixed geometric parameters (focal point on axial symmetry axis, 120° included angle), the system transforms an intractable measurement problem into a solvable calculation problem
3Productivity
If the pass size is incorrect due to measurement errors, then the productivity is maintained, but the quality of steel pipe deteriorates with defects like black threads and internal ellipse defects
Solution Approach 1:
The patent establishes a feedback mechanism where the three-point internal micrometer measures the actual pass dimensions, and these measurements feed into geometric calculations to determine the major semi-axis. This feedback loop ensures that the roller pass processing size is continuously verified and adjusted, preventing quality defects while maintaining production continuity by identifying issues before they cause defects in steel pipes
Data Source
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AI summary
A method for rapidly measuring roller pass major semi-axis of three-roller reducing mill, the method comprising the following steps: selecting a corresponding value of the average diameter of an elliptical pass, a value of a first major semi-axis and a value of a minor semi-axis from a three-roller pass data table according to a rack station number of a special numerical control lathe; calculating a value of a first line segment according to an elliptic equation, the obtained value of the first major semi-axis, and the obtained value of the minor semi-axis; calculating a value of a second major semi-axis according to the right-angle triangle theorem and the value of the first line segment; measuring a first size value by attaching three claws of a three-claw internal micrometer to three roller gaps; or attaching one end of inner calipers to any roller gap, and attaching the other end to the bottom of a roller arc opposite the roller gap to obtain a second size value. The roller pass major semi-axis of the three-roller reducing mill is measured, and the outer diameter precision and the surface quality of a steel pipe are improved.