Computer Aided Engineering for

Metal Die Casting Process

Dr. Laith Abdullah Mohammed / Production Engineering28.April.2009

Die Casting part Examples

This project dealing with die casting process because of:

1-It can widely used for manufacturing complex shaped metallic components (sculptured surface).2-Low manufacturing costs.3-Production of near net-shape.4-Mass productivity and process automation.

Die Casting Basics

Die is closed. Metalis drawn in to tool

(plunger).

Tool injects metal into cavity.

Cavity continues to fill. (fractions

of a second)

Metal solidifies under pressure.

Die is opened.Casting removed.

Machine recovers to initial orientation(cycle starts over)

•Simulation of machining.•Die set components milling Roughening, Finishing on CNC machine.

•3D solid modeling of cast and die.•Check die model.•Draft analysis.•Deviation analysis.•Interference detection.•Undercut detection.•Parting line.•Machine & Die characteristics.

Design Data

Process &

simulation Data

Data features for Die Casting

Process

CNC Cutting Machine

Mathematical Model and

Optimization

Drafting Process

Static analysis: Thermal analysis:

•Design check based on stress criteria. •Thermal distribution based on studying temperature.

•Displacement plot. •dependent of specific heat, thermal conductivity, enthalpy.

•Static strain plot.•Hydrostatic pressure.

•Thermal distribution based on studying surface heat flux.

Machining Data

CAD modeApplied software:

AutoCAD, SolidWorks, MatlabGemoetric data exchange format:

DWG, DXF, SAT

Analysis modeApplied software: ABAQUS, Ansys

Geometric data exchange format: SAT, STL

CAM modeApplied software:

MasterCAM X, ShopMillGeometric data exchange format:

DWG, SAT

Inspection and Measuring Machine

Die Casting Machine

Expert System

Future Work Current Work

CNC Cutting Machine

Drafting Process

The Program (Process Parameters Design – using Matlab envirnoment)

Database for Casting Alloys

http://www.matweb.com

Qtotal: Total heat added to the die by casting (J).Qspray: Total heat removed by spray in each cycle (J).

These result assume cast metal is Aluminum A380 alloy.Thickness of die: 0.088 mVolume of cast : 0.0000506 m3

Working Steps:

1- Create 3D solid modeling of part.2- Forming 3D modeling of die casting using CAD/CAM software. Database required (machining allowance, shrinkage, taper, accuracy and surface rating of the parts, type of alloy).3- Expert system: Process parameters of die casting (Injection pressure, Plunger speed, Gate velocity, filling time, type of alloy, wall thickness, structure of casting).4- Design of gating system, overflows and cooling channels calculated projected area of the cavity and thermal balance of dies.5- Put normalized component parts of dies thickness of inlays distance from the cavity to outer surface of die cover and ejector moulds, cores, gating system, overflows and cooling channels.6- all these modeling data are translated into data files.7- Define the most common defects occurring in casting like air holes and porosity.8- Using simulation software to predict metal flow and solidification in dies and made correction on the design like correct gating system.9- 3D solid modeling of the cavities are machined (machining attributes: cutters, tool path, NC cutter procedures).10- Evaluation of product based on computer measuring machine (CMM).

Features of CAD/CAM system for Mould Casting:1- Define mould geometry.2- validate aspects of mould designs before releasing them for production.3- identify undercuts, complete side cores, verify draft angles, define parting lines, create parting surfaces, assess proper fill characteristics and ensure mould durability.4- access to a complete set of mold bases and standard components.5- Evaluate the mold ability of a part.6- Integration with CNC machining applications.7- integrated product data management: check mold assembly and generate a bill of materials and determine costs.8- Mold design: the first step in designing the cavity and core for a mold is to apply a shrinkage factor to the part based on its material. And suggest the optimal parting line based on the direction of draft within the part. Identify all areas on the part that have insufficient draft.9- create the parting surfaces that define the separation between the core and cavity.10- build the core and cavity of the mold around the surfaces that defined in the tooling split. Then use these solid bodies to create an assembly that is associated to the original multi body part design.11- provide libraries of complete mold bases and components, such as guide pins, guide bushings, ejector plates, ejector housings, and sprue bushings, fasteners, bearings, retaining rings, and Gears, bolts, nuts, and washers.12- determine the stress, strain, deformed shape, and displacement of components during operation to avoid field failures & identify the weaknesses in initial design.

■Take any product from industry (like machine component from automotive factory), and study the complete process plan for this product (from design to finished product) and build complete CAD/CAM system for this product.

■ Study all elements of Die casting machine in the factory, and make a functional enhancement in this machine to be more automatic and production and shorten production cycle time.

■ Focuses on manufacturing complicated product using die casting process (which is difficult to producing before using this method).

■ Studying new alloy which is difficult to manufacturing using die casting method.

Das Rad

Molten Aluminum alloy

Punch

Hydraulic Press

Lower Die

UpperDie

Schematic illustration of the die casting system

Physical properties of Die Material (Tool Steel H13)

Reference Designation (ASTM, ANSI) A360

Reference Designation (Germany) GD-AlSi10Mg

Reference Designation (DIN 1725) 233

Applications offers higher corrosion resistance, superior strength at elevated temperatures, and somewhat better ductility, but is more difficult to cast.

Detailed Composition Si 9-10, Fe 1.3, Cu 0.6, Mg 0.4-0.6, Mn 0.35, Ni 0.5, Zn 0.5, Sn 0.15

Ultimate Tensile strength (MPa) 317

Elongation % (51 mm) 3.5

Yield strength (MPa) at 20°C 170

Hardness (BHN) 75

Shear strength (MPa) 180

Impact strength (J) -

Fatigue strength (MPa) 120

Young Modulus (GPa) 71

Density (g/cm3) at 20°C 2.63

Melting range (°C) 557-596

Specific Heat (J/kg °C) 963

Coefficient of thermal Expansion (µm/m°K) 21

Thermal conductivity (W/m °K) at 20°C 113

Poisson’s Ratio 0.33

Latent heat of fusion [kJ/kg] 389

Non-equilibrium solidification range [°C] 595-555

Physical properties of Die Casting Material (A360)

Solidification simulation model using SolidWorks:

The objective: track the temperature distribution in the Aluminum alloy cast and the mold during the solidification process which occurs over a duration of (4) hours.

Thermal Analysis using Ansys:

Initial conditions

Temperature of die (tool steel) 100 °C

Temperature of cast (Aluminum) 800 °C

Convection heat transfer coefficient (film coefficient)

0.02 N/s mm °C

Ambient temperature 27 °C

Convection occurs between the steel mold and the ambient air.

Element type for mesh Thermal solid, Quadratic 4 nodes

Time step size 0.01

Min time step size 0.001

Max time step size 0.25

Boundary conditions and assumptions:

1. Thermal properties for Aluminum alloy:The enthalpy property table captures the latent heat capacity of the metal as it solidifies. Radiation effects are ignored. Smaller time step sizes will be used during the transition from molten metal to solid state.In this work, we consider (Enthalpy, Thermal conductivity, Specific heat) as temperature related properties.

Enthalpy vs. Temp (°C) Thermal conductivity (J/m s °C) vs. Temp (°C)

Specific Heat vs. Temp (°C)

2. Material properties and Thermal properties for H13 steel:In this work, we consider (Thermal conductivity, Specific heat) as temperature related properties.

Specific Heat (J/g °C) vs. Temp (°C) Thermal conductivity (J/m s °C) vs. Temp (°C)

Nodes profile

Element profile

This work model the thermal aspect of the die casting process. The model simplifies the 3D geometry to symmetrical 3D.Figure shows the dimensions of the 3D geometry.Table reviews the material properties of the die:Work plan in COMSOL Multiphysics v3.31. Specify application mode: Heat transfer module2. Model Geometry definition.3. Physics settings:

A. Subdomain settingsB. Boundary settings (Prescribed temperature)

4. Mesh Generation.5. Solving.6. Postprocessing and Visualization.

Thermal Analysis using COMSOL:

Streamline Map (Total Heat Flux (W/m2))

Sectional Map (Temperature (ºK))

Boundary Map (Temperature (°K))

Temp. distribution:Max.: 1117°KMin.: 328°K

Furnace (Melting Aluminum die casting alloy)

Work benchComputer controlled Thermal Sensors

(Thermocouples K-type)

Experimental Setup

Thermal sensors setup in the die

S1 S2 S3

S5

S7 S6

S4

Thermal Sensors positions

NC Programming Procedures: Prepare the workpiece drawing

Define the workpiece zero Draw in coordinate system Calculate any missing coordinates

Define machining sequence Which tools are used when and to machine which type of contour?

In what order are the individual elements of the workpiece machined?

Which individual elements repeat (possibly rotated) and should therefore be included in a subprograms?

Possibility of perform rotation, mirroring or scaling.

Create machining plan

(Define all the machining processes in steps, e.g.:(Rapid traverse motions for positioning, Tool change, Retract to tool change point, Activiate/Decactivate spindle, coolant, Call tool data, Path override, Approach contour)

Translate the work steps into programming language (Gcodes, APT)

Enter each individual step in an NC block or blocks.

Combine all the individual steps in a program

Siemens CNC controls SINUMERIK 810D/840D/840DI

Technology turning / milling / drilling

Extensive standard cycles

Programming

Comfortable contour calculator / contour lines

Tool administration and management

Graphical simulation

Shop Mill

Shop Turn

Manual Turn

CAD Reader

Programming using SINUMERIK 810D

Shop Mill software

Why choosing SinuTrain ?

Main functions

in

ShopMill control panel

Sectional view 3 Plane view

Volumetric view

Online Control

CAD Reader

Data Printing

Data Management (Copy, Cut, Paste, Mark, New….)

Tool Magazine

Flat End Mill (multi blade cutter)

Diameter (mm) 10

Total length (mm) 112

Cutting part length (mm) 70

Teeth Angle (degree) 30

Number of teeth 5

Type GARANT (Normal)

Material DIN 1835-B (HSS Co8)

Tool code No. 191620

Beneficial: especially for working on low-lying. Difficult to access or to mill large paragraphs in a single operation.

Coolant type Water (max)

ae = 1 x D fz (mm) 0.014

End Tool Angle (degree) 90

Drill

Diameter (mm) 12

Length (mm) 102

Cutting part length (mm) 30

Tool code No. 112000

Material HSS/E (High-speed steel with Cobalt or vanadium)

Cutting Tip Angle (degree) 90

Type DIN 1835-B (Normal)

Coolant type Oil or Water (Max)

f (mm/U) 0.07

In sculptured surface machining, divide the machining surface to multiple planes which are consider as tool path

Volumetric Model(3 Plans, Sectional, Volume)

Machining Program

Tool Manager

Surface Rough Flowline

Tool parametersSurface parametersRough flowline parameters

N5 G17N10 G0G90G54 N10 M5 S50 N10 T219N15 M6N20 G0 X-230.5 Y34.249N25 Z-137.2N30 Z-138.2N35 G1 Z-145.2 F4N40 X-229.629 Y34.271N45 X-228.715 Y34.343N50 X-227.761 Y34.471N55 X-226.768 Y34.664N60 X-225.74 Y34.929N65 X-224.681 Y35.276N70 X-223.598 Y35.713......................N1205 T20N1210 M6N1215 G0G90G54 N1215 M5 S50N1220 G0 X-320.91 Y51.159N1225 Z10.N1230 F2 N1230 MCALL CYCLE82 (10. , 0. , 2. ,-155. , , )N1235 X-320.91 Y51.159 ( Z-155. )N1240 MCALLN1245 M5

Tool Path Generation

Machining Simulation

Finished Product

Finished Product

Tool Path Generation

Machining Simulation

N5 G17N10 G0G90G54 N10 M5 S50 N10 T219N15 M6N20 G0 X-475.246 Y9.688N25 Z25.N30 Z-74.2N35 G1 Z-75.2 F4N40 X-475.898 Y10.384N45 X-476.226 Y10.765N50 X-476.831 Y11.499N55 X-477.389 Y12.269N60 X-477.677 Y12.681N65 X-478.18 Y13.478N70 X-478.425 Y13.917...................................N9635 X-417.432 Y47.54N9640 X-417.391 Y47.476N9645 X-417.11 Y47.07N9650 X-417.066 Y47.01N9655 X-416.755 Y46.627N9660 X-416.707 Y46.572N9665 X-416.491 Y46.341N9670 X-416.44 Y46.291N9675 X-416.107 Y45.983N9680 X-416.055 Y45.938N9685 X-415.899 Y45.813N9690 X-415.526 Y45.599N9695 X-415.105 Y45.511N9700 X-414.677 Y45.557N9705 X-414.285 Y45.733N9710 X-413.966 Y46.022N9715 G0 Z-123.8N9720 Z25.N9725 M5

Machining Simulation

Finished Product

Tool Path Generation

N5 G17N10 G0G90G54 N10 M5 S50 N10 T219N15 M6N20 G0 X-235.564 Y200.784N25 Z-120.939N30 G1 Z-126.939 F4N35 X-235.239 Y200.567N40 X-234.857 Y200.491N45 X-7.139 Y200.49N50 X-6.756 Y200.567N55 X-6.432 Y200.783N60 X-6.215 Y201.108N65 X-6.139 Y201.49N70 Y204.207N75 X-6.215 Y204.589N80 X-6.432 Y204.914N85 X-6.756 Y205.13N90 X-7.139 Y205.207...............................N2455 X19. Y175.35 ( Z-266.739 )N2460 Z-246.739N2465 Y230.35 Z-266.739N2470 Z-246.739N2475 X-261. Y175.35 Z-266.739N2480 Z-246.739N2485 Y230.35 Z-266.739N2490 Z-246.739N2495 MCALLN2500 M5

Thank you