Injection Molding Pressure Curve Matching for Sensorless Parameter Control
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Solution Overview
Problem
Current methods for determining process parameter values in injection molding are costly due to the need for extensive sensor placement within the injection mold, making it expensive to monitor and control the injection molding process across different machines.
Innovation Solution
A method that uses geometry data of the injection mold and form part to simulate a virtual pressure curve, identifying characteristic event patterns which are then matched with real-time measurement data to derive process parameter values without requiring sensors inside the mold cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors and temperature sensors are arranged directly within the cavity of the injection mould to determine machine-independent process parameter values, then measurement precision and reliability of process parameter determination are improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent creates a virtual copy of the injection molding process through simulation. A virtual injection molding process is simulated using the actual mold geometry data, generating a virtual pressure curve that mirrors the real physical process. This virtual model serves as a substitute for physical sensors, allowing process parameter determination without installing expensive sensor equipment within the mold cavity.
Solution Approach 2:
The patent replaces the mechanical/physical sensor-based measurement system with a computational simulation system. Instead of using physical pressure sensors and temperature sensors embedded in the mold, the invention uses computer-based simulation to generate virtual pressure curves from mold geometry data, substituting physical measurement infrastructure with digital modeling.
2Measurement precision
If sensors are placed within the injection mold cavity to monitor the melt front position and determine process parameters, then measurement precision is improved, but manufacturing cost increases due to extensive sensor placement requirements
Solution Approach 1:
The patent creates a virtual copy of the injection molding process through simulation. A virtual injection molding process is simulated using the actual mold geometry data, generating a virtual pressure curve that mirrors the real physical process. This virtual model serves as a substitute for physical sensors, allowing process parameter determination without installing expensive sensor equipment within the mold cavity.
Solution Approach 2:
The patent introduces a virtual pressure curve as an intermediary between the physical mold geometry and the desired process parameters. The simulation uses mold geometry data to generate this virtual pressure curve, which then serves as the basis for determining melt front position and other process parameters, eliminating the need for direct physical measurement within the cavity.
3Device complexity
If a virtual simulation approach is used to determine process parameters without sensors in the mold, then device complexity and manufacturing cost are reduced, but measurement precision may be compromised
Solution Approach 1:
The patent performs preliminary simulation to establish a virtual pressure curve before actual injection molding. The mold geometry data is processed in advance through simulation to create a reference virtual pressure curve that captures the characteristic pressure behavior for that specific mold. This preliminary virtual modeling enables accurate process parameter determination during actual production without requiring complex sensor systems.
Solution Approach 2:
The patent employs feedback by comparing the simulated virtual pressure curve with actual pressure measurements taken during injection molding. The simulation model is validated and refined by comparing its predictions against real-world pressure data, ensuring that the virtual model accurately represents the physical process and maintains measurement precision.
Data Source
AI summary
The invention describes a method of determining a number of process parameter values within an injection mould (1F) during an injection moulding process, which method comprises the steps of determining geometric data of the injection mould (1F) and/or of a form part (1, 1′, 1″) to be manufactured, determining a virtual part-specific pressure curve (pS) of an injection moulding process, determining a part-specific event pattern (MS) on the basis of the virtual part-specific pressure curve (pS), carrying out an injection moulding process using the injection mould (1F) and determining a measured pressure curve (pm) during the injection moulding process and determining a measurement event pattern (Mm) on the basis of the measured pressure curve (pm). Process parameter values are derived on the basis of the virtual event pattern and the measurement event pattern. The invention further describes a corresponding process parameter value determining apparatus and an injection mould arrangement.