The practical application of casting simulation in mold design

The practical application of casting simulation in mold design
Simulation can detect 70% -85% of the shrinkage position in advance, but it cannot replace the trial mold. It can only reduce the trial mold cycle from four rounds to two rounds.
What can simulation solve
The air entrainment, cold insulation, and insufficient pouring during the filling process result in a high degree of agreement between simulation results and actual measurements, usually above 80%.
The accuracy of predicting the location of shrinkage during the solidification process is about 70% -85%. The position of the hot spot is basically accurate, but the quantitative deviation of the shrinkage volume is relatively large.
Simulation can also calculate the temperature field of the mold, which can be used for waterway layout. The value of this aspect in mold design is often higher than defect prediction.
What simulation cannot solve
It is difficult to accurately model the factors of sand core disintegration, coating detachment, and aluminum liquid gas content through simulation.
The mechanical deformation, ejection synchronization, and sealing failure of the mold are structural issues that require finite element analysis rather than casting simulation.
The surface roughness and mold sticking tendency of castings rely on experience and process testing, and the reference values provided by simulation are limited.
The setting of boundary conditions determines the credibility
The interface heat transfer coefficient is the most sensitive parameter. The value deviation is 20%, and the solidification time may deviate by more than 30%.
Suggest using the measured temperature curve to calculate the heat transfer coefficient. Simulations without calibration can only show trends, not absolute values.
The setting of pouring temperature should be consistent with the site. The simulation uses 700 ℃ while the on-site use uses 680 ℃, and the conclusion cannot be matched.
The position of simulation in the development process
The correct sequence is: structural review, simulation, mold design, T0 trial mold. Simulation can only be modified before mold design.
After the mold drawings are produced and simulated, if any problems are found, only minor repairs can be made. Major changes such as gate positioning come at a high cost.
Xinfeng Mold uses simulation as part of the design input for wheel hub and structural component mold projects, rather than as a post validation tool.
How to read simulation results
Look at trends rather than numbers. The position of the shrinkage area is more instructive than the shrinkage rate.
Comparing schemes is more useful than looking at results alone. The difference in filling time and hot spot position between the two gating schemes can directly support decision-making.
The simulation report should include boundary conditions, material parameters, and grid size. Without these three items, the results cannot be reproduced.
Grid and computational costs
The grid size is often taken as 1/3-1/2 of the wall thickness. The mesh is too coarse, and the flow details at the thin walls are lost.
The filling and solidification calculation of a set of wheel hub molds usually takes 4-12 hours. Complex structural components may exceed 24 hours.
When computing resources are insufficient, filling analysis can be performed first, followed by local solidification analysis. Step by step calculation can shorten the cycle.
Configuration of simulation team
Simulation is not something that can be used just by buying a set of software. Parameter calibration requires people who understand both the process and simulation, and such people are even rarer than software.
Small factories can choose to outsource simulation. The simulation cost of a set of wheel hub molds is often between 5000-15000 yuan, which is more cost-effective than maintaining a dedicated team.
Frequently Asked Questions
Question: What is the simulation accuracy?
Answer: Shrinkage position is 70% -85%, and air entrapment is over 80%.
Q: Can simulation replace trial molding?
Answer: No, we can only reduce the trial rounds.
Q: What is the most sensitive parameter?
Answer: The interface heat transfer coefficient is greatly affected by a deviation of 20%.
Question: At which stage should simulation be placed?
Answer: The plan can only be changed before the mold design.
Question: What is the size of the grid?
Answer: Usually take 1/3-1/2 of the wall thickness.
Question: How long does it take to calculate once?
Answer: Wheel hub parts take 4-12 hours, and complex parts take even longer.
Recommended search keywords
Casting simulation, mold design simulation, filling analysis, solidification simulation, shrinkage prediction, wheel hub mold manufacturer, casting CAE, aluminum alloy casting simulation, mold design process, casting process optimization