Define the parameters for a gravity sand casting or gravity die casting process.
Location: Gravity is an option on the Basic Setup icon on the Casting ribbon.
Gravity casting is one of the most common casting processes, as it can be used to produce
a variety of parts, from simple gears and pulleys to complex components such as
automobile engines. The process uses both expendable sand molds and permanent molds to
form metal parts called castings, which can be made of nearly any alloy. The metal is
melted in a furnace and then poured into the mold cavity. Once the casting is
solidified, it is removed from the mold. Variations on gravity casting include
investment casting and tilt pour casting.
Gravity sand casting has few limits on size, shape, and weight, with low pattern and
material costs. However, it is generally less accurate than die casting and has a low
production rate due to the destruction of the molds. Gravity sand casting generally uses
ferrous metals such as stainless steel, carbon steel, and cast iron.
Gravity die casting is a type of permanent mold casting generally used for the
production of small, simple metal parts such as gears, pistons, and wheels. It is
similar to gravity sand casting but with a permanent mold, making it a better choice for
high production volumes. Gravity die casting generally uses non-ferrous metals such as
aluminum, magnesium, and copper alloys, although iron and steel parts can also be cast
using graphite die molds.
Investment casting is a casting process in which the mold is created from a wax pattern,
as follows:
The wax pattern is created manually or by injecting wax in a mold.
The ceramic mold (investment) is created by coating the wax pattern by dipping
it into sand.
The shell mold is dewaxed by heating the pattern.
The molten metal is pored into the hollow mold.
The shell mold is knocked out to get the final cast part.
Tilt pour casting is a permanent mold process where the mold is positioned horizontally
and is gradually tilted upright during the filling process so that it is filled in a
controlled manner with low turbulence and a moderate flow rate. This technique
compensates for the effect of free fall at the beginning of the pouring process, and
helps to avoid air inclusions.
Define Gravity Parameters
Click next to the
Basic Setup icon, then select Gravity.
Select Constant Liquid Level on Sprue,
Filling Time, Spoon Height,
Flow Rate, or Tilt
Pouring.
Note: If you select Constant Liquid Level on Sprue:
When you click Select, you can then select
the point on the sprue where the liquid level should remain
constant.
If more than one ingate is present, you can select a liquid level
for each ingate.
You can also change the initial pouring velocity of the material if
necessary.
Note: If you select Tilt Pouring, the Create
Crucible button becomes active and a new dialog opens to
enter details about the rotation.
Optionally, you may select Investment Casting.
The shell mold will be simulated allowing for analysis of mold temperatures
over time. Use the fields to define shell thickness and initial mold
temperature. Use the menu to select the type of material for the shell mold.
Click the Materials Database icon to select the specific material for the shell mold.
Define the parameters.
Gravity Options
Constant Liquid Level on Sprue
Select this option to maintain a constant liquid level on the sprue
during filling. Click Select, then click the
point on the sprue where the liquid level should remain constant. The
flow rate will change during the filling by adjusting the inlet area to
keep the selected level constant.
Velocity
Use this field to specify the initial velocity of the poured material,
or use the default. When the liquid level reaches the specified point,
the velocity will adjust to keep the level constant.
Filling Time (s)
Select this option if you have calculated the exact filling time
required for your process. Inspire Cast
internally converts the filling time to velocity.
Spoon Height (mm)
Select this option when you have totally manual ladle operators. Spoon
height is the distance between the ladle and the mold when the liquid is
being poured. If you don’t know this value, use a value around 10–30 mm.
Inspire Cast internally calculates the
velocity based on the spoon height.
Flow Rate (Kg/s)
The flow rate is the poured metal volume in Kg divided by the filling
time in seconds. This parameter can be calculated when using an
auto-pour ladle, bottom-pour ladle, stop-and-rod ladle, etc.
Note: The size of the gate area affects the velocity, spoon height, and flow rate.
To simulate a more realistic pouring, we recommend that you don't select the
full area of the pouring cup when defining the gate.
Tilt Pouring
Rotation axis
Select X, Y, or Z to define the axis of rotation. The tilting
rotation follows the same order as the XYZ coordinate axis; if
you select Y as the axis of rotation, then Z will rotate over X;
if you select Z, then X will rotate over Y, and so on.
Move
Move the center of rotation. Right-click
to return to the Tilt Pouring parameters.
Rotation table
Enter values in the time vs angle table. To set a positive or
negative angle, check the sense of rotation from the final
position to the original position following the right-hand rule
to determine the sign.
Preview
Click Preview to check that the sense of rotation selected is the correct one.
Investment Casting
Shell thickness
As the mold in investment casting is only a thin shell, Inspire Cast will use a virtual mesh for it
instead. Enter the shell thickness of the investment mold to
simulate its effect on the part.
Initial mold temperature
Enter the shell temperature at the moment of filling the mold.
Mold material
Use the dropdown menu to choose the type of shell mold material, and
use the materials database to select a specific material.
next to the
Basic Setup icon, then select Gravity.
Note: If you select Constant Liquid Level on Sprue:
to select the specific material for the shell mold. 
