Injection Molding Purge Control via Plasticization Index
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Solution Overview
Problem
Existing control devices for injection molding machines require manual setting of purge conditions, which can be cumbersome for operators and may lead to inefficient resin purging, resulting in thermal degradation and increased production costs.
Innovation Solution
A control device that automatically adjusts the purge operation mode by calculating and matching the plasticization amount index of the resin purge operation with that of the molding operation, using a screw forward/backward movement drive unit, screw position detection, and resin purge control unit to optimize the purge process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual setting of purge conditions is performed, then the operator can control the purge operation, but the operator load increases and setting becomes cumbersome
Solution Approach 1:
The control device automatically determines and sets the purge operation mode by comparing the plasticization amount index of the molding operation with predetermined thresholds, enabling the system to self-adjust without operator intervention. The control device serves itself by autonomously selecting between single-shot purge mode and continuous purge mode based on the calculated index values.
Solution Approach 2:
The system changes the operational parameters of the purge operation dynamically based on the plasticization amount index. When the index exceeds a threshold, the system transitions from single-shot purge to continuous purge, adjusting the purge frequency and duration to match the molding operation's plasticization rate.
2Loss of substance
If purge operation interval is large, then resin consumption decreases, but thermal degradation of resin occurs causing yellowing and carbonization
Solution Approach 1:
The system uses feedback from the plasticization amount index to dynamically adjust the purge operation timing and frequency. By continuously monitoring the plasticization rate during molding operations, the system determines the optimal moment to perform purge operations, ensuring resin is purged before thermal degradation occurs while minimizing unnecessary purge operations that would waste resin.
Solution Approach 2:
The purge operation mode transitions from static predetermined settings to dynamic adjustment based on real-time plasticization amount index. The system adapts the purge frequency and duration to match the actual molding operation conditions, performing continuous purge when plasticization rate is high and single-shot purge when rate is low.
3Object-affected harmful factors
If purge operation is performed frequently, then thermal degradation of resin is prevented, but resin consumption increases and production cost increases
Solution Approach 1:
The control device uses feedback from the plasticization amount index to intelligently determine purge timing, preventing both excessive purge operations and insufficient purge operations. The system monitors the actual plasticization rate and adjusts purge frequency accordingly, performing purge operations only when necessary to prevent thermal degradation.
Solution Approach 2:
The system changes purge operation parameters (frequency, duration, mode) dynamically based on the plasticization amount index thresholds. When the index is below the upper threshold, single-shot purge is used; when it exceeds the threshold, continuous purge is activated, optimizing the balance between preventing thermal degradation and minimizing resin consumption.
4Ease of operation
If automatic adjustment of purge operation mode is implemented, then operator load is reduced, but control system complexity increases
Solution Approach 1:
The control device automatically calculates the plasticization amount index, compares it with predetermined thresholds, and self-determines the appropriate purge operation mode without operator intervention. The system performs self-adjustment by selecting between single-shot and continuous purge modes based on the index comparison results.
Solution Approach 2:
The patent replaces manual operator judgment and manual setting of purge conditions with an automated control system that uses calculated plasticization amount index for decision-making. The control device substitutes the operator's mechanical decision-making process with automated computational logic and control algorithms.
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 solution reduces operator load, prevents thermal degradation of resin, shortens the time to produce non-defective molded articles, and enhances production efficiency by ensuring proper resin purging conditions are set automatically.
Implementation Method 1
a screw (30) which conveys the resin supplied into the injection cylinder (11) toward a nozzle (12) while rotating
Implementation Method 2
a screw forward/backward movement drive unit (26) that moves the screw (30) in a forward/backward direction
Data Source
AI summary
In a control device of an injection molding machine, an operation mode of a resin purge operation is adjusted so that a plasticization amount index related to a plasticization amount of resin per unit time in the resin purge operation is approximately accorded with a target plasticization amount index which is set. Accordingly, thermal degradation of resin can be prevented, active time from start of a molding operation to completion of a non-defective molded article can be shortened, and production efficiency can be enhanced. Further, the plasticization amount index is not necessarily set by an operator, so that a load on the operator can be reduced as well.