Straightness Checking Apparatus for Drawn Bars
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Solution Overview
Problem
Existing methods for verifying the straightness of drawn bars are inadequate for in-line control, often resulting in straightness errors due to uneven wear and incorrect positioning of calibrated holes, which can lead to vibration issues during lathe machining.
Innovation Solution
A checking apparatus with a supporting and moving group that vertically moves bars to a measuring station, using discrete sectors on the supporting planes to minimize friction and allow natural curvature, combined with video cameras for precise straightness measurements, ensuring alignment and accuracy without penalizing production throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous supporting surfaces are used to transport bars, then bars are stable during transport, but friction prevents bars from assuming their natural curved configuration, leading to inaccurate straightness measurements
Solution Approach 1:
The continuous supporting surface is divided into discrete, spaced-apart support elements (rollers or pads) arranged along the transport path. This segmentation reduces the contact area between the bar and support, minimizing friction while maintaining adequate support during transport. The discrete supports allow the bar to assume its natural curved configuration between support points, enabling accurate straightness measurements.
2Reliability
If in-line control of all drawn bars is implemented, then straightness errors are detected, but production throughput is reduced due to additional processing time
Solution Approach 1:
The mechanical measurement system is replaced with an optical measurement system using video cameras and image processing. This substitution allows for non-contact, high-speed measurement of bar straightness as bars move through the apparatus, maintaining production throughput while achieving comprehensive quality control coverage of all drawn bars.
Solution Approach 2:
The measurement process is made continuous rather than intermittent, with multiple video cameras capturing bar straightness data continuously as bars move through the apparatus. This continuous measurement approach detects all straightness errors without stopping production, maintaining full productivity while achieving complete quality control coverage.
3Measurement precision
If drawn bars are allowed to assume natural curved configuration on supporting surface, then straightness errors are revealed, but bars cannot be transported efficiently
Solution Approach 1:
The supporting system is designed to be dynamic, with discrete support elements that can independently move or adjust. This allows the bar to assume its natural curved configuration between support points for accurate measurement, while the support elements continue to transport the bar efficiently through the apparatus. The dynamic nature of the supports reconciles the need for both measurement accuracy and transport efficiency.
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 solution provides accurate detection of straightness errors compatible with state-of-the-art methods while enabling in-line control of all drawn bars, maintaining high production throughput by minimizing friction and ensuring precise alignment with video cameras.
Implementation Method 1
a plurality of video cameras arranged above the supporting and moving group in the vertical direction and parallel and spaced apart from each other in the horizontal direction, and respectively configured to focus a plurality of discrete portions of a drawn bar
Data Source
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AI summary
The invention relates to a checking apparatus (100) for verifying the straightness of drawn bars, said checking apparatus (100) comprising a supporting and moving group (200) adapted to receive a plurality of drawn bars (400) from a drawing apparatus along a horizontal direction (H) and measuring group (300) suitable to measure the straightness of said drawn bars (400). The supporting and moving group (200) comprises a plurality of supporting planes (210) every one of which is configured to receive a drawn bar (400) at picking station (P) of the supporting and moving group (200) and to move it to a measuring station (M) of the supporting and moving group (200) proximate to which the measuring group (300) is arranged, said supporting planes (210) being movable in a vertical direction (V), perpendicular to said horizontal direction (H). The supporting planes (210) are formed of a plurality of sectors (210', 210", 210''') mutually parallel and spaced apart in the horizontal direction (H). The contact between the drawn bars (400) and the supporting planes (210) is limited to plurality of portions spaced apart from each other, which minimizes the contact surface and allows a drawn bar (400) to assume the natural curvature deriving from a drawing process without being influenced by the friction forces resulting from the contact with the supporting plane. Thanks to this configuration it is possible to achieve a precision in the detection of straightness errors that corresponds to the precision obtainable by known checking apparatuses and methods, compatibly with the manufacturing throughput of the drawing plant from which the checking apparatus (100) receives the drawn bars (400). The invention also relates to a straightness checking method carried out by the checking apparatus (100).