Through-roll Profile Unwind Control for Elastomeric Material
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Solution Overview
Problem
Conventional unwind systems fail to compensate for variable machine direction (MD) elastomeric properties in raw materials, leading to increased material consumption, product variability, and downtime in the paper and plastic film industries.
Innovation Solution
A system that passively controls material feed rate and maximum product circumference by using a feed rate equation derived from elastomeric roll sampling and testing, establishing a consistent referenced stretch-to-stop profile to adjust unwind spindle speed, ensuring consistent product sizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional unwind systems are used to maintain constant tension, then web tension control is achieved, but material consumption increases and product size variability occurs due to uncompensated MD elastomeric property changes
Solution Approach 1:
The system performs preliminary sampling and testing of elastomeric rolls to establish a reference stretch-to-stop (rSTS) profile before production. This pre-characterization of material properties enables the control system to compensate for through-roll variations in stretch, basis weight, and thickness, thereby maintaining consistent product size while reducing material consumption.
Solution Approach 2:
The invention changes the control parameter from constant tension to variable feed rate based on the rSTS profile. By using the feed rate equation that incorporates roll diameter and rSTS profile, the system adjusts material feed to account for through-roll elastomeric property changes, achieving consistent product circumference despite material variations.
2Stability of the object's composition
If conventional unwind systems maintain constant tension, then tension stability is achieved, but material consumption increases due to lack of compensation for through-roll stretch variations
Solution Approach 1:
The system transitions from constant tension control to variable feed rate control based on the rSTS profile. The feed rate equation incorporates roll diameter and rSTS profile to dynamically adjust material feed, compensating for through-roll stretch variations and reducing unnecessary material consumption while maintaining product quality.
Solution Approach 2:
The system uses feedback from roll diameter measurement and the established rSTS profile to continuously adjust the feed rate. This closed-loop approach ensures that material feed is optimized based on actual roll characteristics, reducing material waste while maintaining stable production.
3Loss of substance
If feed rate is increased to compensate for high stretch material, then material consumption decreases, but product circumference variability increases
Solution Approach 1:
The system uses the feed rate equation that incorporates both roll diameter and rSTS profile to dynamically adjust feed rate. This ensures that material consumption is optimized while maintaining consistent product circumference, as the feed rate is precisely tailored to the specific roll's stretch characteristics rather than using fixed compensation values.
Data Source
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AI summary
A method of unwinding material in a process system for producing a product (18) includes the steps of loading a roll (12) of material in an unwind system (14) , programming a controller (16) with an unwind equation, the controller in communication with the unwind system, computing a material feed rate based on a predetermined product circumference and an average stretch-to-stop roll profile, and putting a diameter (24) of the roll of material and the material feed rate in the unwind equation of the controller, and unwinding a varying amount of material (26) from the roll of material at a varying unwind speed, the controller being responsive to the unwind equation to vary the unwind speed for forming a plurality of products, each product defining a respective circumference substantially equal to the predetermined product circumference.