LPDC charging simulation Moldflow practical operation, prediction of charging flow field, entrainment, and thermal section, simulation and physical deviation co

LPDC charging simulation Moldflow practical operation, prediction of charging flow field, entrainment, and thermal section, simulation and physical deviation correction
Charging simulation is not just about producing renderings, it is a pre DFM tool; Many simulations only focus on temperature and ignore turbulent flow and liquid surface entrainment, resulting in beautiful simulation results. However, in actual production, there are continuous gas pores and slag inclusions, and the core issue is the mismatch between boundary conditions and on-site parameters.
1、 Quantitative setting of simulation boundary conditions (A356 metal type LPDC)
Aluminum liquid pouring temperature: 720 ℃; The initial temperature of the mold is input by zone: 420 ℃ for the sprue, 280 ℃ for the distal thin wall, consistent with the on-site thermocouple setting.
Pressure curve: Directly import the actual pressure rise curve of the equipment, without using the default uniform pressure rise; The pressure rise rate is the most sensitive parameter for the flow field and entrainment.
Heat transfer coefficient: 300-600 W/(m ² · K) at the cavity aluminum mold interface; Reduce the heat transfer coefficient in the gate area and simulate weak cooling; Increase the heat transfer coefficient at the exhaust port.
Grid: Dense grid for hot nodes, thin walls, and sprue areas; Rough grid, distorted flow field, and failed prediction.
Xinfeng mechanical simulation output: filling liquid level timing diagram, coiling position, hot spot position, solidification sequence, synchronously providing exhaust and gate optimization solutions.
2、 Key points of simulation interpretation, sources of deviation between simulation and physical objects
Qualified flow field: The liquid level is steadily pushed forward without splashing, backflow, or vortex; The liquid level front is continuous, and the gas is orderly discharged from the exhaust groove.
High risk signals: liquid level tearing, vortex, aluminum liquid reflux, premature closure of the front edge, corresponding to high incidence areas of pores and slag inclusions.
Deviation source: The simulation uses an ideal release agent coating, but the actual release agent thickness is uneven and the heat transfer coefficient fluctuates; Changes in the proportion of recycled materials and viscosity of aluminum liquid; Thermocouple drift, mode temperature and simulation input are inconsistent.
Simulation verification method: First article X-ray, metallographic, temperature curve comparison, reverse correction of heat transfer coefficient, iterative simulation model.
3、 Differences in simulation control for overseas customers
Southeast Asian customers rarely conduct mold filling simulations and rely on trial mold modifications, resulting in multiple trial molds and long development cycles.
During the PPAP phase for North American customers, simulation reports must be submitted, and simulation files for filling, solidification, and coiling must be used as tooling approval documents.
The European customer simulation model continues to iterate, updating the simulation boundary conditions synchronously with each mold modification and process change.
For large thick walled castings in the Middle East, the focus is on simulating solidification and shrinkage, with priority given to predicting thermal looseness and secondary consideration of gas entrapment.
4、 Simulation misjudgment failure chain
Directly applying the default constant pressure rise curve, which is inconsistent with the on-site pressure curve → flow field simulation distortion, misjudging the absence of air entrainment;
Unified value of heat transfer coefficient, without distinguishing between sprue, thin wall, and hot spot → simulation error in solidification sequence, failure of porosity prediction;
Rough grid, simplified local flow field → missing vortex vortex vortex location;
If the simulation is completed without physical benchmarking, and the model is not updated for a long time, it will lose its reference value.
5、 Long tail traffic layout ideas
Low pressure casting filling simulation, Moldflow LPDC simulation, solidification simulation, and gas prediction for mold and simulation engineers.
keywords LPDC filling simulation Moldflow、low pressure casting solidification simulation；
Problem class: Heat transfer coefficient aluminum mold LPDC simulation;
Comparison category: Simulation prediction vs actual casting defect LPDC.
Suitable for DFM pre development and mold simulation special pages.
6、 Common misconceptions in the industry
Misconception 1: A good simulation result means stable mass production. If the boundary conditions and on-site parameters are inconsistent, the simulation has no reference value.
Misconception 2: Simulation can completely replace trial molding. Simulation can only predict risks and cannot fully simulate the quality fluctuations of release agents and aluminum liquids.
Misconception 3: Only focus on solidification simulation and ignore the filling flow field. Many pores are filled and rolled, not solidified and loose.
FAQ
Q: LPDC simulation aluminum liquid temperature conventional input?
A: 720 ℃.
Q: Aluminum mold interface heat transfer coefficient?
A：300–600 W/(m²·K)。
Q: The most sensitive parameter in simulation?
A: Boosting rate and pressure curve.
Q: Flow field danger signal?
A: Liquid level vortex, reflux, and front closure.
Q: What are the main reasons for the deviation between simulation and physical objects?
A: Mold temperature drift, uneven release agent, and changes in viscosity of aluminum liquid.
Q: Grid encryption location?
A: Gate, hot section, thin-walled filling end.
Q: North American customer simulation purposes?
A: PPAP tooling approval documents.
Q: Can simulation identify looseness?
A: Solidification simulation predicts thermal looseness.