Variable Heat Transfer Coefficient Injection Molding Simulation
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Solution Overview
Problem
Existing injection molding simulations using a constant interface heat flux overestimate heat transfer, leading to underestimation of resin temperature and viscosity, resulting in inaccurate pressure estimates and potential defects in molded products.
Innovation Solution
A computer-implemented simulation method that calculates variable heat transfer coefficients based on temperature distributions between the resin and mold parts, accurately simulating the injection molding process by considering actual heat transfer phenomena and thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a constant interface heat flux is used in injection molding simulation, then the simulation can be performed with simple assumptions, but the heat transfer is overestimated leading to inaccurate temperature and pressure estimates
Solution Approach 1:
The patent changes the heat flux parameter from a constant value to a variable that depends on resin temperature. The heat flux at the mold-resin interface is calculated as a function of the resin temperature at the interface, allowing the simulation to adapt to actual thermal conditions during injection molding. This resolves the contradiction by maintaining simulation simplicity while improving temperature estimation accuracy through parameter variability.
Solution Approach 2:
The patent implements a feedback mechanism where the heat flux is continuously adjusted based on the calculated resin temperature at the interface. The simulation uses the temperature distribution to determine the appropriate heat flux, creating a closed-loop system that reflects actual physical behavior. This feedback approach eliminates the need for complex boundary conditions while achieving accurate temperature and pressure predictions.
2Ease of manufacture
If a constant interface heat flux is used in injection molding simulation, then the simulation setup is simplified, but the pressure estimates become inaccurate due to incorrect viscosity calculations
Solution Approach 1:
The patent changes the heat flux parameter from constant to temperature-dependent, which directly impacts the temperature field calculation. Since resin viscosity is strongly temperature-dependent, this parameter change propagates through the simulation to improve pressure estimates. The simplified setup maintains ease of use while the temperature-coupled heat flux provides accurate viscosity and pressure predictions.
3Reliability
If trial molding operations are performed to set molding conditions, then the molding conditions can be optimized based on actual results, but the setting time becomes very long
Solution Approach 1:
The patent creates a virtual copy of the injection molding process through computer simulation. The simulation model replicates the physical molding process, including heat transfer, flow, and pressure dynamics. By performing experiments in the virtual model, users can optimize molding conditions without time-consuming physical trials. The temperature-coupled heat flux enhancement makes this virtual copy more accurate, reducing the need for physical verification iterations.
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 provides more accurate temperature and pressure estimates, closely matching measured data, thereby improving the simulation of injection molding processes and reducing defects in molded products.
Implementation Method 1
calculating at least one heat transfer coefficient between the resin part and the mold part taking into consideration the plurality of temperature distributions at different times
Data Source
AI summary
A molding method includes the steps of specifying a simulating domain having a resin part and a mold part, wherein the simulating domain corresponds to a genuine domain on a molding machine; setting an initial resin temperature of the resin part and an initial mold temperature of the mold part; performing a transient state analysis to calculate a plurality of temperature distributions at different times between the resin part and the mold part; calculating at least one heat transfer coefficient between the resin part and the mold part taking into consideration the plurality of temperature distributions at different times; simulating the molding process of a molding resin that is injected into the simulating domain by using the at least one heat transfer coefficient to generate a plurality of molding conditions; and performing the molding process by using the plurality of molding conditions to the genuine domain on the molding machine.