Calender Stack Axial Offset Adjustment for Film Thickness
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Solution Overview
Problem
Calender stacks face challenges in maintaining uniform film thickness due to roller deflections, leading to complex control systems and thickness profile deviations across the film width.
Innovation Solution
The calender stack incorporates an advanced adjusting system with dual bearings and a rack-and-pinion mechanism, allowing for precise axial offset adjustments between rollers to compensate for deflections, ensuring a constant gap and uniform thickness, utilizing a servomotor and planetary gear for precise control and minimal play.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single adjusting system is used for the advancing roller, then the structure is simple, but roller deflections cause non-uniform film thickness across the width
Solution Approach 1:
The adjusting system is divided into two independent subsystems: a first adjusting system for nip adjustment and a second adjusting system for axial offset adjustment. This segmentation allows each subsystem to address specific aspects of thickness control, with the second system compensating for deflection-induced thickness variations by laterally shifting the advancing roller relative to the stationary roller.
Solution Approach 2:
The solution moves from one-dimensional nip adjustment to two-dimensional control by introducing axial offset adjustment in a direction perpendicular to the nip adjustment direction. This additional dimensional degree of freedom enables compensation for roller deflections that cause thickness variations across the film width.
2Manufacturing precision
If complex control systems are used to measure and compensate thickness profile deviations, then film thickness uniformity improves, but control complexity increases
Solution Approach 1:
The second adjusting system performs preliminary compensation for expected roller deflections by pre-positioning the advancing roller with an appropriate axial offset. This preventive adjustment reduces the need for complex real-time measurement and control systems, as the majority of thickness profile deviations are compensated in advance.
Solution Approach 2:
The invention changes the geometric parameter of the roller arrangement by introducing an axial offset between the advancing and stationary rollers. This parameter change alters the gap profile across the roller width, enabling compensation for deflection-induced thickness variations without requiring complex control algorithms or measurement systems.
3Manufacturing precision
If the advancing roller is offset axially relative to the stationary roller, then roller deflection compensation improves, but the adjusting system complexity increases
Solution Approach 1:
The adjusting system is divided into two independent subsystems: a first adjusting system for nip adjustment and a second adjusting system for axial offset adjustment. This segmentation allows each subsystem to address specific aspects of thickness control, with the second system compensating for deflection-induced thickness variations by laterally shifting the advancing roller relative to the stationary roller.
Solution Approach 2:
The second adjusting system, while adding a new function, is designed with a structure similar to the first adjusting system (rack and pinion mechanism), allowing for standardized components and simplified manufacturing. The modular design reduces the overall complexity increase despite the additional 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 solution enables precise adjustment and compensation for roller deflections, resulting in a uniform film thickness profile, reducing raw material waste and setup times, and improving product quality by minimizing thickness deviations and operational complexity.
Implementation Method 1
the first and/or second adjusting system has a rack and a pinion, which engages with the teeth of the rack and can be driven in rotary fashion by a motor
Implementation Method 2
utilizing a servomotor and planetary gear for precise control and minimal play
Data Source
AI summary
A calender stack including at least two rollers between which a nip can be formed. The ends of the rollers are supported in rotary fashion in bearings and one of the rollers is stationary and at least one other roller is embodied as an advancing roller and has a first adjusting system by which it is possible to move the bearings of the advancing roller, thus changing the nip. The advancing roller has a respective adjusting system on each of its two bearings and associated with each first adjusting system, a second adjusting system is provided, by which it is possible to adjust an axial offset of the advancing roller relative to the stationary roller.