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SOLIDCast UNIT 3: Setting System Parameters

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When you first install SOLIDCast it is a good idea to check out and properly set your System Parameters. A moment spent now making sure things are correct can head off many problems before they get a chance to start. From the main SOLIDCast menu click on Tools…System Parameters.

There are 5 tabs; Alloy Curves, Model Colors, Model & Sim, Directories and FLOWCast.

The Alloy Curves tab, as shown below, lets you set up default values for new materials in your casting alloy database. These will also be applied if you ever reset material properties to defaults in the Materials List.


The Default Critical Fraction Solid %(CFS) is the value assumed to be the end of feeding, or metal movement, for a casting alloy. As freezing begins, the metal becomes thicker and pastier, until, at the CFS, it stops moving altogether. If feed metal hasn’t been available to counteract any shrinkage that has been occurring, it will not be able to get to that point after it has reached the CFS. This value varies by alloy type and section size, but good starting points would be:

Plain Carbon Steels:                 50% for large sand castings to 35% for small investment castings

Alloy Steels:                               45% for large sand castings to 30% for small investment castings

Aluminum:                               20% – 30%

Copper Base:                           25% – 35%

Cast Irons:                            Adjusted by the software

 

The Default Niyama Point % is the percent solid at which the Niyama value is calculated. The Niyama Criterion is made up of the Temperature Gradient at a point, divided by the square root of the Cooling Rate at the same point. This value is an indicator of the degree of directional solidification and the likelihood of shrinkage formation. The lower the value, the greater the potential for shrinkage formation. This is normally calculated at a point just after the CFS. A good starting point is 5% after the CFS point.

The Default Solidification Shrinkage % is the amount of expansion or contraction that a metal undergoes during the cooling and solidification process. A negative value indicates overall shrinkage, or contraction, while a positive value indicates expansion. Most materials will shrink on cooling, so the value should be negative in most cases. A typical value would be 7% for shrinking alloys. Cast irons are a notable exception, and the shrinkage curves for gray and ductile cast irons are modified by the software.

The Model Colors tab, shown below, gives you full control of how the colors of a casting/mold model are displayed. There are special colors for Casting, Riser and Fill materials. Mold materials have 8 different colors. If more than 8 mold materials are used in a single model, the 8 colors will be reused in order.


There is also a color selection for the currently selected shape, which is used to highlight a model piece during editing.

 

You can change these values to any of a set of standards, or create your own color in a customized palette.

The Model & Sim tab, shown below, contains the defaults for measurement system, snap and the time step interval for Volumetric Calculations. It also has entries for the maximum number of facets displayed in an iso-surface plot, a toggle for displaying data graphically during simulation, and the redraw interval for the graphic display.

 

The system default for measurements is English units, that is, inches. If you check the Use Metric Measurements box, units will convert to millimeters. Temperatures will be in degrees C, rather than degrees F, and all other units will convert as well.

Snap to Grid allows you to set a snap value for the Model Builder, so that you can draw to a specific interval. For example, you could set the snap increment to every 1/8 (0.125) inch, or to every 2 millimeters.

The Volumetric Calculation Interval defaults to every 10 time steps, which means that 1 volumetric feeding calculation will be done for every 10 sets of temperature calculations. Volumetric calculations are more involved and take longer to do than temperature calculations. For longer simulations, this number can be increased. It is recommended, however, that this number be at least at a 1% increment during solidification. For example, if a simulation will take 5000 time steps, a 1% increment would be every 50 time steps. Of course, you don’t know the number of total time steps BEFORE a simulation runs, so this value will be based on experience with similar simulations.

The Iso-Surface Maximum Facets value tells your system when to automatically change the detail value when plotting iso-surfaces. By limiting the maximum value, you can keep plotting times down. If this number gets too high, complicated models can take quite some time to plot. A good starting point for this is 1,000,000, and since graphics cards are getting more and more powerful, the time factor is constantly reducing.

Display Temperature Data Graphic During Simulation and Graphic Display Interval control the picture shown during a simulation. If the Display checkbox is cleared, only a summary text screen will be displayed. If checked, a color picture of the filling and solidification is shown. The Graphic Display Interval tells the system to redraw the temperature distribution after the listed number of time steps. The larger the interval, the fewer times the screen will be redrawn and the faster the simulation will run. For the fastest possible simulations, turn off the Graphic Display.

 

The Directories tab, shown below, lets you set up default locations for Projects and Import Files. Click on the Browse… button to navigate to a new directory. When you see the open folder in the Select a Path window, you know that is the current directory.




It is a good idea to set up the Projects path to an existing directory, such C:\Projects. Then, when you create new projects, the system will create new directories underneath this one.

The Import Files path is usually set to where you keep your STL CAD files, if you will be bringing them into SOLIDCast. This is also where the system will store movie files created by the movie functions in SOLIDCast.

The FLOWCast Tab, shown below, sets default values for the FLOWCast fluid flow simulation, if started by SOLIDCast.

Save Time Step interval This tells the system how often a full save of data will be done. A full save allows you to restart a fluid flow simulation at any saved increment. It also determines how many frames, or pictures, can be put into a filling movie. If the save interval is smaller, then more data is saved and more pictures can be created for a movie. At the same time, the overall file size will be larger.

Warmup Mesh interval This is the point at which data is saved for a warmup mesh in a permanent mold simulation. In general, we do not need data during the warmup phase of a permanent mold simulation, and are mainly concerned with only the temperature distribution in the die. The default value of 99 means that only one time step is saved during fill of the warmup mesh.

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