Rolling Mill Coil Stitch Positioning for Strip Thickness Stability
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Solution Overview
Problem
Existing rolling systems for metal band material face challenges in maintaining consistency due to band train disorders, particularly the 'bundfall' issue, which affects the thickness and quality of the rolled material.
Innovation Solution
The procedure involves defining specific tape locations on the metal band material at precise angle positions relative to a reference point, ensuring that these locations are distributed optimally over the coil to minimize bundling and maintain consistent thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strip material is wound onto a mandrel during rolling, then the metal strip undergoes thickness reduction and is processed, but coiling occurs causing irregular coil shape and cyclical tension disturbances that degrade strip quality
Solution Approach 1:
The invention applies preliminary action by defining a specific strip point at a predetermined distance from the strip head before winding begins. This strip point is positioned at an angular distance of 90° to 180° from the reference position on the mandrel, so that when the strip is wound, this point creates a local diameter reduction that compensates for the coil's out-of-roundness. The strip point is tracked during passage through the rolling mill, and rolling parameters are adjusted in advance to ensure the strip point passes through the rolling stand at the optimal moment, thereby preventing tension disturbances before they occur.
2Reliability
If coil beat compensation is applied using acceleration additives on the reel and positioning position adjustments, then tensile disturbances are counteracted, but the process becomes complex and requires extensive optimization
Solution Approach 1:
The invention applies parameter changes by fundamentally altering the approach from active compensation to passive prevention. Instead of using complex acceleration additives and positioning adjustments, the method changes the spatial parameter of where the strip point is located relative to the strip head, and changes the temporal parameter of when rolling actions are applied. By defining the strip point at a specific angular distance and tracking its position, the system uses simple parameter monitoring and adjustment rather than complex multi-variable control, thereby maintaining tension stability while reducing system complexity.
Data Source
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AI summary
The invention relates to a method for operating a rolling mill with at least one rolling stand for rolling strip material and a corresponding rolling mill. According to the method according to the invention, the rolled strip is first threaded into the rolling stand F1 with its strip head leading, subsequently reduced in thickness according to a pass plan, and then wound with its strip head leading into a coil 220 using a reeling device 110.To reduce coil roll, the inventive method provides that, prior to performing the stitching operation, a strip point K is defined at a distance from a reference position on the strip material 200 such that, when the strip material is wound onto the mandrel, strip point K lies at an angular position with a predetermined angular distance β to the angular position of the reference position R, where β is: β > -1° or β < -10° if the coil 220 is wound from above, or β > 10° or β ≤ 1° if the coil 220 is wound from below. The strip material is then tracked as it passes through the rolling mill so that the stitching operation can be performed at the first strip point K on the rolled strip.