Stretching Rod Speed Control for Plastic Bottle Wall Thickness
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Solution Overview
Problem
Existing methods for transforming plastic preforms into bottles struggle to adjust wall thickness distribution during the blowing operation efficiently, requiring complex interactions among multiple control variables and resulting in costly, technically complex apparatus.
Innovation Solution
A method that uses a measuring device to monitor wall thickness and adjust the stretching speed of the stretching rod via a closed-loop or open-loop control system, allowing for real-time adjustment of wall thickness distribution using a single control variable, thereby simplifying the production of mechanically stable and cost-effective containers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple control variables (pre-blowing timing, pressure, flow rate, heat settings) are adjusted to control wall thickness distribution, then manufacturing precision of wall thickness is improved, but device complexity and control difficulty increase significantly
Solution Approach 1:
The patent extracts and isolates the stretching speed parameter from the complex system of multiple control variables. By focusing on a single extracted parameter (stretching speed) rather than managing all variables simultaneously, the control system becomes simpler while still achieving wall thickness control objectives.
Solution Approach 2:
The patent changes the control parameter from a combination of multiple variables (timing, pressure, flow rate, temperature) to a single parameter (stretching speed). This parameter change simplifies the control system architecture while maintaining the ability to influence wall thickness distribution through the relationship between stretching speed and material flow during blowing.
2Manufacturing precision
If multiple control variables and complex interactions are used to adjust wall thickness distribution, then manufacturing precision is improved, but ease of operation deteriorates due to susceptibility to faults and operational complexity
Solution Approach 1:
The patent extracts the stretching speed as the sole control variable, removing the need to manage complex interactions between multiple variables. This extraction makes the system easier to operate and less susceptible to control faults while preserving the ability to achieve precise wall thickness distribution.
Solution Approach 2:
Instead of controlling wall thickness by adjusting blowing parameters (pressure, timing, temperature), the patent inverts the approach by controlling wall thickness through stretching speed. This inversion simplifies the control logic and makes the system more robust against operational errors.
3Adaptability or versatility
If individual blowing stations are controlled individually with multiple parameters, then adaptability of wall thickness adjustment is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the control of each blowing station independently, allowing individual adjustment of stretching speed at each station. This segmentation provides adaptability for different bottle requirements while keeping each station's control simple and avoiding the need for complex coordinated control across multiple stations.
Solution Approach 2:
The patent makes the stretching speed parameter universal for controlling wall thickness across all blowing stations. Instead of using different control variables at different stations, the same parameter (stretching speed) serves the multi-functional purpose of wall thickness control throughout the entire system, reducing overall complexity.
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 approach enables easy and individual adjustment of wall thickness distribution during the blowing operation, reducing the need for complex control variables and apparatus, resulting in more stable and economically viable plastic bottles.
Implementation Method 1
the plastic preforms are expanded to form the plastic bottles by being acted upon by a gaseous medium in the blow mould
Implementation Method 2
a wall thickness of the plastic container is measured by means of at least one measuring device, for example during the blowing operation
Implementation Method 3
at least a stretching speed of the stretching rod is varied by the closed-loop and/or open-loop control device at least at times and/or at least in some locations during the blowing operation
Data Source
AI summary
A method for transforming plastic preforms into plastic bottles, in which preforms are introduced into blowing stations, each blowing station having at least one blow mold and a stretching rod for stretching the preform along a longitudinal axis of the preform within the blow mold, and the preforms are expanded to form the plastic bottles by being acted upon by a gaseous medium in the blow mold, wherein a wall thickness of the plastic container is measured by at least one measuring device which outputs the measured values to a closed-loop and/or open-loop control device, wherein at least a stretching speed of the stretching rod is varied by the closed-loop and/or open-loop control device at least at times and/or at least in some locations during the blowing operation, individually for each blowing station, in order to adjust a wall thickness of the plastic bottles.