Casting simulations are notoriously complex due to the wide range of physical processes present in the casting process. For example, most casting processes include heat transfer, solidification and melting, air entrainment, cavitation, and surface defect generation. There may be numerous geometry components such as dies/molds, cores, cooling channels, shot machines, and pouring ladles. Additionally, the user must create computational meshes, define metal filling locations, and define output data. With all this information on the screen, simulation setup can be challenging. FLOW-3D Cast v4.2 uses the What You See Is What You Need (WYSIWYN) design methodology places the most important information at the top level so that users can quickly see and act on what options need to be set.
Following the design principle of WYSIWYN, FLOW-3D Cast v4.2 introduces the first process-oriented workspace for high pressure die casting. Users are guided through the distinct stages of a high pressure die casting process – thermal die cycling, filling, solidification, and cooling. The user interface recognizes each sub-process simulation and automatically applies both required and best practice settings that save the user time and prevent common mistakes from occurring.
The new die spray cooling model, developed in collaboration with Audi AG, gives FLOW-3D Cast users the ability to model all facets of die preparation, taking into account the influence of the shape of the mold surface and the position and the movement of the spray nozzles. Being able to accurately model this important stage of high pressure die casting improves users’ ability to achieve high quality parts.
HPDC Process-Oriented Workspaces
The high pressure die casting (HPDC) process can typically be defined by four distinct sub-processes – thermal die preparation, filling, solidification in the mold, and cooling in air. Casting simulations of these sub-processes require different numerical settings such as implicit vs. explicit, simulation termination conditions, restart options, and physical model selections. Moving from one sub-process to another can be quite time consuming for users as they must remember what to change. Process workspaces simplify HPDC simulations by automatically applying appropriate settings to a simulation based on the process and sub-process type.
Process environment settings are used with the Process Oriented Workspaces to automatically set simulation parameters that are associated with environmental conditions. For example, the pressure in a gas region is automatically set to the environmental pressure. Environment variables include initial die temperature, ambient pressure and temperature, pour superheat, and gravity direction.
A global button has been added to place high-level information at the top level. The pour metal properties have been moved here and, if the simulation is in a process-oriented workspace, the user can quickly determine what the process and subprocess of the simulation is.
A new switch has been added to easily control thermal depth penetration in a process-oriented workspace by automatically turning thermal penetration depth on or off depending on the subprocess. This flag also makes it easier for the user to activate or deactivate the thermal penetration depth without having to remove the actual thermal penetration values from the simulation.
One of the most challenging aspects of casting simulations is the proper specification of the many required heat transfer coefficients. This new release includes heat transfer databases for cooling channels (including a wide range of flow rates, diameters and coolants), contact heat transfer, liquid-to-solid heat transfer, solid-to-air transfer, and liquid-to-gas heat transfer. Also, a heat transfer database covering all stages of thermal die preparation (open to air, spray cooling, blowing air and closed) is included.
WYSIWYN – What You See Is What You Need
This new release features a streamlined user interface designed with a focus on WYSIWYN – What You See Is What You Need. The FLOW-3D Cast v4.2 interface makes simulation setup more efficient and error free by providing a consistent layout and a flat design that shows users the most important simulation information on the top level. This new design has been applied to meshing, boundary conditions, initial conditions, baffles, metal inputs, and more. Setting up heat transfer is now a breeze with an intelligent, context-sensitive, heat transfer coefficient panel.
Visualizing Non-Inertial Reference Frame Motion
Results from the non-inertial reference frame model can be visualized from a stationary frame of reference. This is a new feature within FlowSight. This new feature allows results from simulation such as tilt pouring and centrifugal casting processes to be visualized as they actually move rather than in a static reference frame.
Die Spray Cooling Model
To further enhance the already unique and powerful thermal die cycling modeling, a sophisticated spray cooling model has been developed that can model individual sprays, their movement, and their heat transfer. In order to accurately predict the temperature distribution in the die during the spray cooling phase, the spatial variation in the spray applied to the die should be modeled. Spray cooling model is developed for this purpose. The Die Spray Cooling model explicitly computes the cooling from each spray, instead of a constant heat transfer coefficient across the entire die cavity. The spray area on the die surface will be computed and updated constantly due to the movement of the spray nozzles. The blocking of the spray cooling due to the spray angle and the shape of the die surface is also considered. It provides more accurate temperature distribution on the die surface, which will help users better design and optimize thermal die preparation to produce higher quality die castings.
Simulation courtesy of Audi AG