Casting Process
Modeling Using
SOLIDCast®
What is SOLIDCast®?
SOLIDCast® is the world’s best-selling casting
process modeling software from Finite
Solutions, Inc. This package, formerly sold as
AFSolid 2000, is now in use in more than 400
companies and schools in over 40 countries
around the world.
SOLIDCast® is a PC-based software tool that
simulates the pouring of hot metal of virtually
any casting alloy into sand, shell, investment or
permanent molds, and the subsequent
solidification and cooling process.
What makes SOLIDCast® Work?
SOLIDCast® uses the Finite Difference
Method(FDM) of heat transfer calculation,
combined with a unique tracking of volumetric
changes in the metal, to predict the temperature
and volume changes in a casting as it is poured,
solidified and cooled.
This combined thermal-volumetric approach has
proven to be an extremely accurate method of
predicting various casting problems, including
micro- and macro-porosity, hot spots and other
defects.
What is Casting Process Modeling?
Casting Process Modeling is a mathematical way to
let the computer predict(simulate) what will
happen when a casting is poured on the shop
floor.
Virtually anything that can be modified in the
foundry can be simulated using Casting Process
Modeling. Simulation allows you to fine tune
your casting process in much less time, and
without the waste of expensive materials, than
shop floor trials.
What are the benefits?
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Shorten Lead Times
Help Solve Problems
Optimize Existing Jobs
Train Employees
Improve Customer Relations
Attract More Jobs Through Improved Market
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So, how does Casting Process
Modeling work?
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Select Materials and Properties
Build Casting/Mold Model
Mesh Model/Run Simulation
Evaluate Results
Modify and Re-simulate
Select Materials and Properties
The first step in modeling is to select the materials
that will be used in the simulation. This includes
the casting alloy, as well as all mold materials.
SOLIDCast® contains databases with over 230
casting alloys in all the major groups, plus data
on all common mold materials.
You can also use chills, insulation, exothermics
and cooling/heating channels in permanent mold
dies.
Select Materials and Properties
• Properties That Control Heat Flow in a Mold
Material
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Thermal Conductivity
Specific Heat
Density
Initial Temperature(s)
This screen capture of the Mold Tab shows typical
properties for a cast iron chill. All common molding
sands are included, plus insulating and exothermic
materials. You can add, modify or remove materials at
any time.
Select Materials and Properties
• Casting Alloys Also Require
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Solidification Temperature
Freezing Range
Latent Heat of Fusion
Solidification Curve
Volumetric Change(Shrinkage) Curve
The Casting Tab
has additional data,
since the casting
alloy will change
from a liquid to a
solid during the
simulation.
The Solidification and Shrinkage
curves define the freezing behavior for
each casting alloy. These can be
modified by the user, and cast iron
curves can be developed based on
chemistry and molding method.
Select Materials and Properties
• Heat Transfer Coefficients Control Heat Flow
Between Materials
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Mold Coatings
Air Gaps
Cooling Channels
Convection/Radiation
Heat Transfer Coefficients(HTCs) are used to
define how heat flows across surfaces. They are
most often used in permanent mold casting, to show
coating effects, and in investment casting, to show
radiation effects from the hot shell.
The top pictures show 2 investment casting models…
…The bottom pictures show the radiation ‘view factors’
Build Casting/Mold Model
Once you’ve created a “Materials List”, which tells
the system what materials will be used in your
simulation, you need to build the casting/mold
geometry.
This step is the most user-intensive part of the
process, but, as you will see, there are many
time saving ways of building models.
Model Building Techniques
• Direct import of 3D CAD data
• Import of 2D CAD data > 3D
• Blueprints
– Digitizing
– Shapes, Drawing, 2D CAD
3D STL File Import
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Most CAD systems have it
Triangles cover the part surface
One file for each material(casting, chills, cores)
Binary smaller than ASCII
This model of a cylinder head was created using 4 STL files,
one for the casting, two for core assemblies and one for the
sleeves.
2D DXF File Import
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Every CAD system has it
Auto-trace utility can extract cross-sections
Extrude, rotate or blend sections to create 3D
Exact data as created by CAD operator
Drawings may have problems, but can be
corrected
The 2D DXF file shown above
became the 3D solid shown at the
right. Sections from the CAD file
were extruded, rotated and
blended to create 3D geometry.
Working With Blueprints - Digitizing
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Fast input
Multiple scales are ok
Hardware is inexpensive
CAD looks better, but simulation results are the
same
With a digitizing tablet and a
blueprint, you can trace 2D sections
that will be rotated, extruded or
blended into 3D models, such as the
investment cast valve bodies shown at
the right.
Working With Blueprints
Shapes, Drawing, 2D CAD
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Requires greatest time and operator effort
Good for gating/risering systems
Doesn’t require other software
Works best when all dimensions are listed
This aluminum
permanent mold
casting took over a day
to build, using only a
blueprint and 2D CAD.
However, the
improvements made
due to simulation
saved the foundry over
$700,000 per year on
this part alone!
(Note that the die
pieces have been
removed for clarity.)
Run Simulation
Once you have the “Materials List” and the casting
geometry, you can put the two together in a
process called Meshing. The meshed model is a
series of cubes, called nodes. Each node has
different material properties, as defined in your
materials list.
The meshed model is like a big series of Lego
bricks, all of which are shaped like cubes. A
meshed model may have millions of cubes, and
the heat transfer equations are applied to each
cube, over and over.
This pictures shows
a meshed model
of casting plus
risers, including
insulating and
exothermic sleeves
and chills.
The number of
cubes used in a
mesh is limited only
by available
memory.
This picture shows the
mold cavity as it is being
meshed. This can be done
automatically using
SOLIDCast®.
During the mold
Temperatures Duringfilling simulation,
Filling Sequence the relative
temperatures are
shown on the
screen, so you can
see hot and cold
spots develop. Heat
is being lost to the
mold and
surrounding air.
After mold filling
is complete, you
can watch the
progression of
Temperatures Duringsolidification.
Gray areas show
Solidification Sequence
solidified metal,
and temperatures
can be seen in the
cooling metal.
Notice that
volumetric feeding
is calculated at the
same time as
temperature.
Interpreting Results
Once a simulation is complete, you can look at
various pieces of data to decide whether you
have made a good part or a bad one.
Since this decision may be based on different
factors for each casting, SOLIDCast® provides
many types of data for your use.
What Data Can be Plotted?
•Temperature During Fill and Solidification
–Displayed during the simulation, or as a single time
plot
•Time
–Liquidus
–Critical Fraction Solid
–100% Solid
–Local Solidification
•Hot Spots (Isolations)
–Based on CFS
–Based on 100% Solid
What Data Can be Plotted?
•Temperature Gradient
•Cooling Rate
•Material Density
•Criteria Functions
–Niyama
–FCC (Micro-porosity)
–User Defined Functions
How Can Data Be Plotted?
•CastPic Plot
–3D color plot at any orientation
–Cut planes can be active
•Iso-Surface Plot
–Surface at a given value
–Surrounds ‘worse’ values
–Good for time or density plots
•Cut-Plane Plot
–2D slice from the 3D model
–Good detail, plus individual data
•CastScan Movies
–Color plot on a transparent casting
–Progressive or rotating
This CastPic
plot show the
progression of
Critical Fraction
Solid (CFS)
Time on a valve
body casting.
The casting has
been cut in half
so you can see
what is
happening
internally.
Progressive Solidification
Critical Fraction Solid Time Range
(CastPic Plot)
This screen is
an iso-surface
plot of the FCC
Criterion, used
to predict
microporosity
in castings.
Notice that the
tendency
towards
shrinkage
varies
depending on
position in the
mold.
This is a Cut Plane
Plot. You can drag the
cut plane through the
model, and a 2D plot
will be created
instantly.
This plot also shows
CFS Time, which
shows when feeding
ends.
Movies – Animating your plots
Each of the plot types can also be created in a
movie format. You can control the number of
frames, how fast the movie runs, and the range
of data displayed.
These movies are saved in the Windows standard
AVI format, so you can send copies to your
customers and they can run them on any
Windows PC, without any extra hardware or
software.
The next screen shows samples from a movie.
Modify Model and Re-simulate
Simulation is an iterative process. Once you have
evaluated results, most often you will find something
that needs improvement. When you do, you have a
number of options available. Basically, anything that can
be changed on the shop floor can be simulated to a
certain extent using SOLIDCast®. For example, you
can…
• Change Geometry
• Change Process Parameters
• Change Rigging
The Payback - Casting Examples
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Steel Investment Cast Food Processing Part
Aluminum Permanent Mold Automotive Part
Steel Sand Cast Elevator Part
Cast Iron Sand Cast Compressor Body
Investment Casting - Steel
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3 patterns via rapid prototyping
2 failures by conventional methods
13 simulations in 1 1/2 weeks
$500,000 per year new business
saved 26-39 weeks lead time
The figure on
the left is the
initial rigged
geometry. The
iso-surface plot
on the right
shows material
density.
You can see
shrinkage-prone
areas moving
from the gating
system into the
casting.
The final model,
with a top ring riser,
gives acceptable
results.
Note that shrinkage
was not completely
eliminated in this
case, but was
reduced and moved
into an acceptable
area of the casting.
Permanent Mold - Aluminum
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High Volume Brake Component
7% Shrinkage Rejects on Machining
Now <0.4% Rejects
$700,000/Year Savings
With the original gating, the
last place to freeze was in the
casting, not the riser. When
this area was bored out, the
shrinkage was exposed and
the casting was scrapped.
By changing the riser shape
and increasing the contact size,
the last point to freeze was
moved into the riser, and the
casting is now shrink-free.
Sand Casting - Steel
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Behind in delivery of new casting
9 risers but still had shrinkage
12 simulations with feedback
10 working days to complete job
5-6% yield improvement
Better quality at a reduced cost
Without simulation to
show the hot spots, this
casting was over-risered,
yet still had unacceptable
shrinkage.
Simulation pointed out where
the real problems lay, allowing
an intelligent risering scheme
to be applied, resulting in
higher yield AND higher
quality.
Sand Casting - Cast Iron
• Gray iron compressor body
• High yield, but shrinkage in green sand
• Simulations run for green sand and no-bake
molding systems
• No-bake provided good results
This gray iron
compressor body
was cast in the
green sand process,
but had internal
porosity.
By switching to a
no-bake process,
the mold was more
rigid and shrinkage
was eliminated.
Simulated X-ray results.
Green Sand Mold
No-Bake Mold
The world’s best-selling modeling
software
The world’s most cost-effective
simulation package
Where can I find more
information?
Contact Finite Solutions, Inc:
Dave Schmidt
Phone: 847-398-5162
Email: FiniteIL@aol.com
Larry Smiley
Phone: 513-821-5220
Email: LSmiley1@aol.com
Or visit www.finitesolutions.com