Cyclic Tension Control for Packaging Machine Tube Formation
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Solution Overview
Problem
Existing packaging machines for producing sealed packages of pourable products face challenges in maintaining precise and reliable tension control of the packaging material, leading to variations in package formation and quality.
Innovation Solution
The packaging machine incorporates a tensioning device with a main drive roller and auxiliary drive roller, controlled by a cyclic speed profile synchronized with the package forming cycle, along with a control unit that adjusts the angular speed and acceleration of the main drive roller to maintain consistent tension, and includes a free loop mechanism to manage tension variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tensioning device with constant rotation speed is used to control tube tension, then the average advancement speed is maintained, but the tension varies uncontrolled during cyclic package formation operations
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant speed control system to a dynamic speed control system. The drive motor's rotation speed is continuously adjusted according to a pre-defined cyclic speed profile that matches the package forming cycle, allowing the tensioning device to adapt to varying operational demands and maintain precise tension control throughout the cyclic process.
Solution Approach 2:
The patent implements periodic action by using a pre-defined cyclic speed profile that repeats with each package forming cycle. The drive motor's rotation speed follows this periodic pattern, synchronizing the tensioning device's operation with the cyclic nature of package formation, thereby maintaining consistent tension control across multiple cycles.
2Use of energy by moving object
If the drive motor maintains constant rotation speed, then energy consumption is reduced, but the tension control precision deteriorates during cyclic operations
Solution Approach 1:
The patent uses periodic action with a pre-defined cyclic speed profile that optimizes energy consumption. The drive motor's rotation speed follows this periodic pattern, increasing speed only when necessary during the package forming cycle and reducing speed during less demanding phases, thereby balancing energy efficiency with tension control precision.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the drive motor's rotation speed parameter according to the cyclic speed profile. This allows optimization of both energy consumption and tension control precision by varying the speed parameter in response to different phases of the package forming cycle rather than maintaining a constant high speed.
3Device complexity
If a simple tensioning device is used, then device complexity is reduced, but the ability to compensate for cyclic speed variations is insufficient
Solution Approach 1:
The patent implements feedback by using a pre-defined cyclic speed profile that is synchronized with the package forming cycle. The drive motor's rotation speed is continuously adjusted based on this feedback mechanism, allowing the tensioning device to compensate for cyclic speed variations and maintain reliable tension control without requiring complex real-time sensing and control systems.
Data Source
AI summary
A packaging machine comprises a conveying device for advancing a web along a web advancement path at least to a tube forming station where the web is formed into a tube and for advancing the tube along a tube advancement path, a tube forming and sealing device configured to form and to longitudinally seal the tube, a tensioning device upstream of the tube forming station and configured to control the tension of the tube and a control unit configured to control packaging machine operation. The tensioning device comprises a main drive roller rotatable around a main rotation axis and a main drive motor configured to actuate rotation of the main drive roller around the main rotation axis. The control unit is configured to control the main drive motor such that angular speed and/or angular acceleration of the main drive roller is cyclically varied to control the tension of the tube.