Injection Molding Booster Valve Timing Control
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Solution Overview
Problem
Existing injection apparatuses face challenges in achieving suitable boosting characteristics, leading to issues such as burrs and sinks due to inadequate timing of the boosting process, which is difficult to optimize with existing control methods.
Innovation Solution
The apparatus includes a control device that manages the transition from injection speed control to pressure control by adjusting the opening degree of the servo valve after initiating the booster valve, allowing for improved pressure control and reduced delays in boosting, thereby enhancing the boosting characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the threshold value of the plunger speed is set relatively high to avoid delay in boosting start, then the response time is improved, but burrs are formed due to excessive plunger speed. If the threshold value is set low to prevent burrs, then manufacturing precision is improved, but delay time increases causing sinks or mold cavities
Solution Approach 1:
The control device opens the booster valve in advance before the plunger speed actually reaches the threshold value. By predicting when boosting should start based on predetermined conditions (injection amount, injection speed, threshold value), the system prepares the boosting mechanism proactively, eliminating delays while controlling plunger speed to prevent burrs
Solution Approach 2:
The system dynamically adjusts the opening degree of the injection control valve during the transition from injection to boosting. The control device gradually changes the valve opening based on real-time plunger speed feedback, enabling smooth transition that prevents both burrs and delays by continuously optimizing the control parameters
2Productivity
If the threshold value is set high to reduce delay time, then productivity is improved, but burrs are formed. If the threshold value is set low to prevent burrs, then manufacturing precision is improved, but productivity decreases due to delay time
Solution Approach 1:
The control device continuously monitors plunger speed and uses this feedback to dynamically control the injection control valve opening degree. By comparing actual plunger speed with target values and adjusting the valve in real-time, the system achieves both high productivity and high quality without the need for conservative threshold settings
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 improves the boosting characteristic by reducing the likelihood of burrs and sinks, ensuring more consistent and efficient molding processes.
Implementation Method 1
a booster piston capable of pressurizing a hydraulic fluid (for example oil) behind the injection piston
Implementation Method 2
by supply of hydraulic fluid from an accumulator or other hydraulic pressure source to the back of the injection piston, the plunger moves forward
Data Source
AI summary
A control device of an injection apparatus outputs a control command to a hydraulic pressure device to perform injection by supplying hydraulic fluid to the back of an injection piston 15 from an accumulator 25 and, at this time, to execute speed control for controlling the speed of the plunger by an opening degree of an injection control valve. Further, the control device outputs a control command to the hydraulic pressure device to perform boosting by opening a booster valve to supply hydraulic fluid to the back of the booster piston and pressurizing the hydraulic fluid behind the injection piston by the booster piston and, at this time, to execute pressure control for controlling the pressure of the molding material by an opening degree of the injection control valve. Further, the control device can start outputting a control command for pressure control after start of outputting a control command for opening the booster valve in transition from injection to boosting.