International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
Design and Validation of a Casting Die
Priyanka Vispute#1, Digambarchaudhari*2, Reeti Mukherjee#3
#
Department of Mechanical Engineering, Gokhale Education Society’s, R H Sapat C.O.E.M&R,
Nashik,422005,India
*
Asst. Prof. at Department of Mechanical Engineering, Gokhale Education Society’s, R H Sapat C.O.E.M&R,
Nashik,422005,India
#
Asst. Prof. at Department of Mechanical Engineering, VignanaBharathi Institute Of Technology, Hyderabad,
501301, India
Abstract—The function of casting die is to hold the
molten metal in the shape of desired casting so that the
molten metal get solidify and finally removed out of
die as a solidified casting. The design of the die is
vital in determining the quality of the part produced.
This paper mainly focus on the design phase for the
die for an automobile component made of aluminium
alloy (AIDC12). The design phase for the casting die
involves discrete selection of design parameters
namely, type of gate, location of the gate, Type of
runner and its geometry, position for overflows and so
on. Work involves designing the Casting die while
securing crucial inputs from the `flow simulation’ for
the calculation of number of air vents. The same is
validated using the radiography tests. The Results
shall be documented for offering as a quick generic
reference for all the other part akin in form and
features.
Keywords—Analysis, Design, Die Casting, Flow
Simulation
I.INTRODUCTION
Die casting has increasing application in
automobile aerospace, household appliances industries
due to high strength and good performance.Four basic
functions of the casting die-(1) hold the molten metal
in the shape of desired casting (2) provide a means for
the molten metal to get into the space where it is to be
held in the desired shape(3) remove heat from the
molten metal to solidify the metal and (4) provide for
the removal of the solidified casting. Hence quality of
casting component is determined by the die with
which the component is formed. [6]
The Design phase for the Die Casting Die
involves discrete selection of Design parameters
namely, type of Gate, location of the Gate, Type of
runner and its geometry, number of air vents and
position for overflows. Overflow locations are placed
appropriately based on flow simulations. Die casting
enterprises need to produce high quality die castings
in shorter period with lower cost. The production
period of casting can be significantly reduced by
introducing CAE system with computerized casting
analysis that will reduce the cost and time required.
Due to the complex shape of casting components large
scale Different employed methods for casting
simulation are - Finite Difference Method (Solid Cast),
Finite volume Method (MagamaSoft), Finite Element
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Method (ProCast), and Vector Element Method (Auto
Cast). Out of these our focus is on Magma Soft
In the current study a casting die is designed
andinvestigated for best solution. Numerical
simulations have been found to be very useful in
finding the best solution amongst calculated designs
and also for defect proofing of die from various
possible defects like gas porosity, cold shut, shrinkage
cavity, air bubbles etc. Validation of work is
performed by radiographic experimentation of
component manufactured through die.
II. LITERATURE STUDIES
- Alexandre (2012) studied the rate of metal flow in
the channel is much higher than the solid-liquid
interface velocity. The flow in the thin cavity is
treated as two-dimensional after integrating the
momentum and continuity equations over the
thickness of the channel, while the heat transfer is
modeled as a one-dimensional phenomenon in the
thickness direction.
- Bodhayanaet al. (2014) investigated that die casting
was a versatile manufacturing technique in which
molten metal is poured into die. The die consists of
core and cavity, an impression is formed when these
core and cavity are closed together. This impression
forms the shape and size of the component. The main
challenge in die casting is design and manufacturing
of die. Integration of design and analysis yields to
better results.
- Swamyet al. (2012)investigated on conventional
gating design casting defects such as shrinkage and
gas porosities were found in front axle housing a
critical automotive component. This component is
generally made out of spheroid graphite iron. A
flawed gating system was found to be the reason for
improper fluid flow and melt solidification which in
turn produced casting defects
- Sung et al. (2008) carried out computer simulations
to analyze the flow of molten metal and analyze
effective mould design. Optimal conditions are
calculated through simple equations examined using
experimental outputs.
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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
III. PROBLEM DEFINITION
For current work, the die cast component
named Case Gear Meter is considered for research
over the most suitable design for Die. The design for
the components has focused on aesthetics and
function. The design and development phase is aimed
to be short and effective. The Design for the Die holds
a key in effecting a good quality product in a lesser
turnaround period of development. The problem here
was to identify the design parameters for the die
casting die while manipulating the inputs for desirable
responses i.e. output parameters. The same have been
deployed through analytical tool for simulation of the
die casting process with the result for key variation
made for the best outcome for product quality i.e.
minimization of defects through suitable Design. The
design parameters namely, the type and location of the
Gate, the Runner system and the overflow have been
studied for concluding the design phase for the die.
IV.SOLUTION METHODOLOGIES
The flow simulation represents the analytical
solution for the problem. Suitable CAE software
would be deployed for modeling the problem and
applying the constraints with the input parameters.
The working conditions were defined over the
interface along with application of the properties for
the melt. The simulation have determined the nature of
flow; fill time for the die, occurrence of any defect in
the form of blow holes or deflection upon cooling.
The nature and the magnitude or prominence of the
defect would be evident while realizing the solution
using this Analytical tool.
This approach of problem solving have
deployed CAD and CAE practices for arriving at the
most suitable solution to the design problem at hand.
The geometry would be modelled using CATIA for
the dimensions of the product. This imported in the
interface of the pre-processor for discretising the
geometry. Further, flow simulation carried out using
Magma Soft. Then deployed for evaluating the nature
of flow with respect to time taken during filling as
well as identifying potential threats to quality in terms
of defects like blow holes, shrinkage, porosity,
unfilled cavity. The characteristics of this component
in terms of the aspects of quality is evaluated for
determining the success of the design phase.
V.DESIGN
Product information
Fig.1-3D diagram of Component to be manufacture
( made up of material- Aluminium alloy AIDC 12)
Design of Case Gear Meter Casting Die System
Die Material: Hot Die Steel H-13 .Principal Design
Feature of this alloy is one of the Hot Work,
Chromium type tool steel. It also contains
molybdenum and vanadium as strengthening agents.
The chromimum content assists this alloy to resist
softening if used at higher temperature .[8]
Table No. I: Chemical Composition of H-13[7]
content
Wt.(%)
carbon
0.32-0.45
chromium
4.75-5.5
molybdenum
0.2-0.5
Phosphrous
1.1-1.75
Sillicon
0.03 max
Sulpher
0.8-1.2
Vanadium
0.03 max
Table No. II : Physical properties of H-13[7]
Density(lb/cu.in.)
0.283
Specific Gravity
7.8
Melting point(0F)
2600
Modulus of Elasticity
29
Model calculation:
1) Part Projected Area: 2428.00mm2
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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
2) Overflow Projected Area:364.00mm2
3) Slide Projected Area= ( *6*6*2*tan 10)[5]
=19.93mm2
4) Total Part Projected Area=(Part Projected
area)+(Overflow
Projected
Area)+(Slide
ProjectedArea)[5]=
(2428)+(364)+(19.93)
=
2
5623.86mm
5) Runner
Projected
Area=(Part
Projected
Area)+(3040% More) [5]=3797.00mm2
6) Total Projected Area=(Total Part Projected
area)+(Runner Projected Area)[5] = 9420.86 mm2
7) Tonnage of Machine = (Total Projected
Area)+(Casting
Pressure)+(Die
Locking
Force)[5]=210 Tonnes
VI. MODELLING AND MESHING
Fig.3- Layout of casting die
8) Shot Weight = (Weight Per Cavity) +
(Runner+Biscuits)[5]= 313.00gm
9) Filling Ratio=
[5]
= 3.73
10) Cavity Fill Time (t) =K*T*
=
.
[6]
0.034
Where,
K-Emperical constant=0.034 sec/mm.
T-Casting thickness =4 mm
Ti-Temperature of molted metal as it enters the die
=6800c.
Tf-Minimum flow temperature =6300c
Td- Temperature of die cavity surface =1200c
S-Allowable percent solid fraction
Its selection depends upon casting thickness, per 4mm
thickness its 20.
z-Units convergion factor =3.8
[5]
11) Gate Area=
= 63.180 mm2
Hence,
Gate length=32 mm
Gate Thickness=2 mm
Above diagram shows the meshing diagram
of Case Gear Meter die. Solver used for meshing is
Magmasoft version 5. Total number of elements are
83328. Solid mesh type mesh is chosen.we have
chosen this type of mesh as per the geometry.t
This is mapped mesh. Element type is tetrahedral.
Element size is 4. Accuracy of mesh quality is
confirmed on basis of following criteria:
Warpages > 5.00
Aspect ratio > 5.00
Skewness > 60.00
Net collaps < 0.5
Jacobian < 0.7 and trial faces: Minimum angle < 20
and Maximum angle > 20
[5]
12) Flow Rate =
3
= 2527233.115 mm /sec
13) Plunger velolcity =
= 2011.10 mm/sec
Plunger velocity = 2.01 m/sec
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Fig.2- Mesh diagram of casting die
VII.RESULT AND DISCUSSION
[5]
After calculating all the design parameters
like gate velocity, Gate area, metal temperatureand
cavity fill time next task was to finalize total numbur
of air vents for die. Total number of air vents are
decided byback pressure analysis in magmasoft.
According to the standard if the value of back pressure
of entrapped air in casting cavity is more than 2 bar
then it will lead to air porosity after machining of
casting.
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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
Table No. III : Calculated nput boundary
conditions for magmasoft analysis
Parameters
Values
HighVelocity (m/sec)
2.0
Switch over point (mm)
339
2
Gate area (mm )
62
Gate Velocity (m/sec)
41
Cavity FillTime (sec)
35
Material temp (oc)
680
o
Die temp ( c)
analysis result with one air vent where air pressure
value observed is upto 4.1 bar. by adding one more air
vent in further analysis along with same boundary
conditions. Fig.7 shows that air pressure valuewithtwo
air vents is reduced to 1.3 max with two air vents.
Hence, two number of air vents are finalized.
VIII.EXPERIMENTAL RESULTS OF
RADIOGRAPHIC TEST
150
Above boundary conditions are given and results of
back air pressure are documented as follows:
Fig.6- radiographic test results
Fig.4- Air pressure analysis result with one air vent
After finalizing all the parameters of the
die.The castingdie has been manufactured. For
validating the manual design calculations and analysis
with magmasof,t rediographic test has been performed
on the first componant manufactured from die. Fig.6
showsthe results of resiographic test. From figure it
can be clearly seen that product is not having any
defects like air bubbles,hot spots, shrinkage cavities,
gas porosity on it’s surface. Hence design paremeters
are validated.
IX.CONCLUSION
[1] From above disscusion Design parameters are
calculated as gate velocity 41 m/sec, metal
temperature 680 deg.Gate area 62 mm2 and cavity fill
time 35 sec.
[2] It have been seen that value of maximum back
pressure should be less than 2 bar to avoid air
entrapped and gas porocity hence maximum back
pressure is reduced upto 1.3 bar with aditional venting.
[3] Total number of air vents finallized from analysis
are two.
[4] From rediographic test result it have been seen that
there are no defects on the surface of componant
hence, design is validated by radiographic test result.
Fig.5- Air pressure analysis result with 2 air vents
REFERENCES
This result shows the back pressure of
entrapped air in casting cavity. As alresdy discussed
if this value is more than 2 bar then gas porosity difect
will occure on the surface of componant after
machining of casting. Fig.5shows the air pressure
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in Thin Cavities Using Lubrication Approximation‖ The University
of Wisconsin-Milwaukee, December 2012, PP. 65-70.
[2] Bodhayana M. R., N. Ramesha ―Tool design for pressure dies
casting of Housing Component‖ International Journal on
Theoretical and Applied Research in Mechanical Engineering
Volume -3, Issue-2, 2014, PP. 30-33.
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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
[3] ManjunathSwamy H. M., J. R. Nataraj, C. S. Prasad ―Design
Optimization of Gating System by Fluid Flow and Solidification
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2012,PP. 83-88.
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[5] E.A.Herman―Die casting dies‖ 2ndEdition ,Society of die casting
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[6] http://www.NADCA.com.
[7] http://www.suppliersonline.com.
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