Injection Molding Machine Pressure Control for Resin Flow Rate
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Solution Overview
Problem
Existing injection molding machines struggle to accurately control the flow rate of resin discharge due to variations in resin grade, temperature, and nozzle size, leading to inconsistent molding results.
Innovation Solution
An injection molding machine and additive manufacturing apparatus that calculate a target pressure based on resin grade, temperature, and nozzle size, using processors to control the pressure and flow rate by adjusting the movement speed of a piston, incorporating a pressure control unit and pseudo-plastic viscosity calculations to ensure precise flow rate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressure control is executed without considering resin grade, temperature, and nozzle size, then the control system is simple, but the discharged flow rate varies and molding precision deteriorates
Solution Approach 1:
The system changes control parameters (target pressure values) based on resin grade, temperature, and nozzle size. The storage unit stores multiple target pressure values corresponding to different combinations of these parameters, and the control unit selects the appropriate target pressure based on current conditions, thereby achieving precise flow rate control without complex real-time calculations
Solution Approach 2:
The system performs preliminary preparation by pre-calculating and storing target pressure values for various resin grades, temperatures, and nozzle sizes before actual molding operations. This allows the control system to simply retrieve and use pre-determined values during operation, avoiding complex real-time computations while maintaining high precision
2Manufacturing precision
If target pressure is calculated without considering temperature and pseudo-plastic viscosity, then calculation is simpler, but discharged flow rate control accuracy deteriorates
Solution Approach 1:
The system incorporates temperature and pseudo-plastic viscosity as key parameters in determining target pressure. The storage unit contains target pressure values that already account for the complex relationships between temperature, viscosity, and flow rate, allowing accurate control without performing complex real-time viscosity calculations
Solution Approach 2:
The system replaces complex real-time physical calculations with pre-computed lookup tables. Instead of calculating pseudo-plastic viscosity and its effect on flow rate in real-time, the system substitutes this with pre-stored target pressure values that encapsulate these complex relationships, simplifying the control mechanism while maintaining accuracy
Data Source
AI summary
An injection molding machine includes a cylinder that accommodates a molten resin, a discharging nozzle, a piston that discharges the molten resin from the discharging nozzle, and one or more processors configured to execute the following functions. The functions include calculating a target pressure at which a flow rate of the molten resin discharged from the discharging nozzle becomes an indicated flow rate, controlling a pressure of the molten resin in the cylinder such that the pressure becomes the target pressure, acquiring a temperature of the molten resin in the cylinder, and acquiring a pseudo-plastic viscosity corresponding to the temperature of the molten resin. The target pressure is calculated based on the indicated flow rate, the temperature of the molten resin, the pseudo-plastic viscosity, and the size of the discharging nozzle.