Cross-Direction Fiber Orientation Control via Spatial Frequency Modeling
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Solution Overview
Problem
Existing web manufacturing processes face challenges in controlling cross-direction fiber orientation, leading to quality issues such as paper jams, mis-register in color printing, twist in multi-layer boards, and poor runability of high-speed newsprint due to poor fiber orientation properties.
Innovation Solution
A method and apparatus for modeling and controlling cross-directional fiber orientation processes, involving the generation of models that identify spatial frequency characteristics and dynamic adjustment of parameters using actuator edge padding and model predictive control to regulate fiber orientation angles and minimize twist in multi-layer products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fiber orientation control methods are used, then manufacturing process is simple, but product quality deteriorates due to poor fiber orientation properties causing paper jams, mis-register, twist, and poor runability
Solution Approach 1:
The fiber orientation control problem is segmented into spatial frequency components (low frequency for overall orientation, high frequency for local variations and edge effects). This allows the control system to address different aspects of fiber orientation separately, improving control precision without requiring a completely complex monolithic system.
Solution Approach 2:
The system performs preliminary modeling and identification of spatial frequency characteristics before actual control. By pre-characterizing the process behavior at different spatial frequencies, the control system can anticipate and compensate for fiber orientation issues, improving quality while maintaining manageable complexity.
2Manufacturing precision
If spatial frequency characteristics are identified for accurate fiber orientation control, then manufacturing precision improves, but measurement and detection difficulty increases
Solution Approach 1:
The system uses an intermediary modeling approach where complex spatial frequency measurements are transformed into a simplified mathematical model. This model acts as a mediator between the complex physical measurements and the control system, making the measurement process more manageable while preserving the detailed spatial frequency information needed for precise control.
Solution Approach 2:
The system replaces direct complex physical measurements with a mathematical modeling approach. Instead of directly measuring and reacting to complex spatial frequency variations, the system uses a mathematical model to represent and predict fiber orientation behavior, simplifying the measurement and control process.
3Manufacturing precision
If actuator edge padding is applied to capture severe edge effects, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The system applies local quality by treating edge regions differently from the bulk of the web. Actuator edge padding is specifically applied to capture and control severe edge effects, while the rest of the system operates with standard control parameters. This localized approach improves edge quality without requiring complete system redesign.
Solution Approach 2:
The system applies partial action by using actuator edge padding only where severe edge effects occur, rather than uniformly across the entire web. This targeted approach provides sufficient control for edge regions without the full complexity of a uniformly enhanced control system across all areas.
Data Source
AI summary
A method includes generating a model associated with cross-directional fiber orientation of a web, which includes identifying spatial frequency characteristics of a fiber orientation (FO) process. The method also includes providing the model for control of the FO process. Generating the model could include performing a spatial impulse test of the FO process, and long wavelength responses of the FO process can be identified by performing a spatial long wavelength test of the FO process or by retrieving information from a historical database. Actuator edge padding can be applied to the model in order to generate a controller model. A controller can be used to control the process based on the controller model. At least one parameter of the controller model can be dynamically adjusted during operation of the controller. The controller can change average fiber orientation angle profiles and twist profiles by only adjusting slice lip actuators in a headbox.