Sheet Forming Apparatus Roll Gap Control
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Solution Overview
Problem
Existing sheet forming apparatuses face challenges in automatically adjusting the roll gap and sheet take-off speed, leading to issues such as soft sheets, surface defects, and motor overload due to manual adjustments and delayed changes in roll gap settings during changes in extrusion amounts or forming conditions.
Innovation Solution
A sheet forming apparatus equipped with roll gap adjustment and measurement means, along with pressing load control, allows for automatic adjustment of the roll gap and sheet take-off speed based on measured deviations from target values, enabling constant pressing load or roll gap control modes to maintain optimal forming conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual adjustment of roll gap is used, then operator can observe melt bank size, but adjustment is delayed and causes surface defects or motor overload
Solution Approach 1:
The system uses a sensor to detect melt bank size and feeds this information back to the control unit, which automatically adjusts the roll gap. This closed-loop feedback mechanism eliminates manual observation delays and prevents surface defects or motor overload by maintaining real-time control.
Solution Approach 2:
The patent replaces manual mechanical adjustment with an automatic control system that uses sensors and actuators. The control unit processes sensor signals and automatically positions the rolls, substituting human operation with an automated electromechanical system for faster and more precise adjustments.
2Quantity of substance
If roll gap is widened to accommodate increased extrusion amount, then melt bank size is controlled, but sheet cooling is insufficient and sheet hangs down
Solution Approach 1:
The system dynamically adjusts the roll gap based on real-time extrusion conditions. When extrusion amount increases, the roll gap is automatically widened to prevent melt bank overflow, and when extrusion decreases, the gap is narrowed to maintain proper sheet cooling and prevent hanging, ensuring continuous optimal forming conditions.
Solution Approach 2:
The control system changes the roll gap parameter in response to variations in extrusion amount. By automatically adjusting this critical parameter, the system maintains appropriate sheet cooling and prevents manufacturing defects while accommodating different production rates.
3Temperature
If roll gap is narrowed to improve sheet cooling, then sheet hardening is sufficient, but melt bank grows large causing bank marks
Solution Approach 1:
The sensor continuously monitors melt bank size and provides feedback to the control unit. When the melt bank approaches problematic sizes, the system automatically adjusts the roll gap to prevent bank marks, while maintaining sufficient cooling through optimized roll contact pressure and positioning.
4Speed
If simple proportion operation is used to change screw speed, then extrusion amount is adjusted, but roll gap changes before extrusion amount changes causing sheet hanging or motor overload
Solution Approach 1:
The system uses sensors to monitor actual extrusion amount and roll gap positioning, providing continuous feedback to the control unit. This ensures that roll gap adjustments are synchronized with extrusion changes, preventing sheet hanging or motor overload that occur with simple proportion operation.
Solution Approach 2:
The control system performs preliminary adjustment of the roll gap in anticipation of extrusion changes. When screw speed is changed, the system proactively positions the rolls before the full extrusion change occurs, maintaining stable forming conditions and preventing defects.
Data Source
AI summary
The present invention enables an automatic roll gap adjustment, thereby facilitating operations at a set-up or when changing forming conditions. Specifically, one embodiment of the present invention controls a sheet take-off speed (a roll rotation speed) in accordance with a deviation of a measurement value from a set value of a roll gap under a constant pressing load control.