Gas Dissolution Detection in Plastic Melt Injection Moulding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In injection moulding, undissolved gas in plastic melts leads to defects like bubble flaws, distortion, and unusable components due to incomplete gas dissolution, resulting in significant wastage and geometry deviations.
Innovation Solution
A method and computer program product that determine the dissolution state of gas in plastic melts by calculating compression parameters, such as the modulus of compression, to assess complete gas dissolution or solubility limits, allowing for real-time adjustment of pressure to ensure gas is fully dissolved during the moulding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gas is added to the plastic melt during plasticisation, then the plastic component can be foamed or expanded, but undissolved gas causes bubble flaws, gas cushions, streaks, and severe distortion leading to unusable components
Solution Approach 1:
The patent applies preliminary action by performing compression tests on the plastic melt before the actual injection moulding process to determine the dissolution state of gas. This advance measurement allows operators to adjust gas injection parameters beforehand, ensuring complete gas dissolution during the subsequent production process and preventing defects like bubble flaws and distortion.
Solution Approach 2:
The patent implements feedback by using compression test results to determine whether gas is completely dissolved in the plastic melt. This information feeds back into the process control, allowing adjustment of gas injection parameters based on actual dissolution state, thereby preventing undissolved gas from causing component defects.
2Reliability
If compression tests are performed on the plastic melt to determine gas dissolution state, then complete gas dissolution can be ensured, but the testing process may disturb the plastic shaping process
Solution Approach 1:
The patent extracts the measurement function from a separate external device and integrates it directly into the injection moulding machine's control system. The compression tests are performed using the machine's own components (injection unit, cylinder, temperature control), separating the measurement function while using existing hardware, thus minimizing disruption to the production process.
Solution Approach 2:
The injection moulding machine performs self-measurement by using its own injection unit and temperature control system to conduct compression tests on the plastic melt. This self-service approach eliminates the need for external testing equipment and operators, allowing the machine to autonomously determine gas dissolution state without significantly disturbing the production process.
3Measurement precision
If separate external devices are used to measure gas dissolution state, then accurate measurements can be obtained, but transmission of measurement results and coordination with the shaping machine adds complexity
Solution Approach 1:
The patent merges the measurement system with the injection moulding machine by integrating the compression test functionality directly into the machine's control unit. The evaluation device is combined with the injection unit and temperature control system, eliminating separate external measurement devices and simplifying the overall system architecture while maintaining measurement accuracy.
Solution Approach 2:
The injection moulding machine's control system is designed to perform multiple functions: it controls the injection process, maintains temperature, and conducts compression tests to measure gas dissolution state. This multi-functionality eliminates the need for separate dedicated measurement equipment, reducing system complexity while preserving measurement precision.
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 reduces wastage and defects by ensuring complete gas dissolution, maintaining component geometry integrity, and simplifying the process by integrating measurements directly within the shaping machine, minimizing disruptions to the moulding process.
Implementation Method 1
outputting at least one second actuation signal to the shaping machine for altering—in particular reducing—a volume of the chamber, whereby a pressure of the plastic melt together with the gas is altered, in particular increased, from a first pressure value to a second pressure value
Implementation Method 2
it is important that the gas added to the plastic melt is substantially completely dissolved
Data Source
AI summary
A method of determining a solution state of a gas in a plastic melt used in a plastic shaping method includes:(vi) providing the plastic melt together with the gas in a chamber,(vii) altering—in particular reducing—a volume of the chamber to alter a pressure of the plastic melt together with the gas—in particular increased from a first pressure value to a second pressure value,(viii) introducing the plastic melt into a shaping cavity,(ix) computing at least one compression parameter characteristic of the compression behaviour of the plastic melt, in particular a modulus of compression, from the first pressure value and the second pressure value, and(x) determining from the at least one compression parameter whether the gas is substantially completely dissolved in the plastic melt and/or a solubility limit of the gas in the plastic melt is determined from the at least one compression parameter.