Lost Core Neue Perspektiven Im Druckguss Dario Pierri Buhler Ag

8/13/2019 Lost Core Neue Perspektiven Im Druckguss Dario Pierri Buhler Ag

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Lost Core - neuePerspektiven imDruckguss

Dario Pierri,

Bhler AG

FHNW Giessereitag 2013


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Introduction to Lost Core Technology.

Basic Idea of Lost Core Technology.

Using lost cores in the HPDC process to create undercuts orfluid ducts.

Integrating additional functions inHPDC parts.

Reducing machining, sealing and assembling.

INNOVATIVE TECHNICAL SOLUTIONS WITH LOST CORE TECHNOLOGY.



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Overview of Different Lost Core Technologies.

Lost Core Technologies

OtherTechnologies

Melt

OutGas

InjectionTubes

Sand Cores

Inorganic Organic Croning

Salt Core Technologies

Solid Phase

PressedShotBlast

Liquid Phase

Semi-solid

100%Liquid

Coatings

Sintered or notSintered



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Properties of Salt Core Technology.

ADVANTAGES

No use of chemicalbinders. No use of coating. No use of toxic salts.

CHALLENGES

Ceramic behavior (brittle). Needs to be demolded for

HPDC process. Limited in volume

dimensions.

PROPERTIES

Smooth surface quality. High resistance to heat. Water soluble. Thermal insulator.

Volkswagen AG BOCAR3D-Freiformflchen Projekt

EXAMPLES

3D-Free-form Surfaces Project Volkswagen AG Bhler AG



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Salt Core Simulation.

Material properties of salt mixture.

salt core specimen

Material property Solid Liquid

Solidustemperature - ca. 640C

Liquidustemperature - ca. 690C

Density 2.3 2.5 kg/dm3 1.7 1.9 kg/dm3

Specific heat 1.0 1.4 kJ/kg*K 1.6 1.9 kJ/kg*K

Thermal conductivity 2 - 4 W/m*K 1 - 2 W/m*K

Latent heat of fusion - ~ 400 kJ/kg

Thermal expansion 4e-05 6e-05 K-1 -

Viscosity - 1 - 2 mPas

Youngs Modulus > 10000 N/mm2 -

Poisson ratio 0.18 0.24 -

Avg. bending strength > 18 MPa -



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Possibilities of simulation.

Simulation with materials salt and aluminum.

Aluminum Casting

Design of gating andventing system Check of flow circulationaround salt core

FSI Simulation

Fluid-Structure-Interaction:Calculation of forces affectingthe salt core during fillingprocess

Salt Core Production

Design of gating andventing system (salt die) Pre-check of shot profile Check of solidification



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Aluminum Simulation.

Results of FSI Simulation.

Prediction of stresses on coresurface by using Fluid Structure

Interaction Simulation.

Comparison of impact due todifferent ingate velocities.

Finite Elements Method - Mesh (FEM)

Velocity 1~ 40 m/s

Velocity 2~ 80 m/s

Velocity 3~ 120 m/s



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Part and Die Design for Lost Core Technology.

Salt core

Research of Shrinkage behavior.

Part design of salt core.

Die design for salt core production

Gating system design for salt core.

Thermo balance of the salt core die.

Salt core positioning before aluminum casting

New design ideas for HPDC partsHPDC die; Symposium sample



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Process steps.

Overview of production chain.

Insert Salt

Core

DosingMixing

Melting

Stock / Quality

Salt stockSalt Casting

Salt Core

removal /

recyclingQualitycheck

AluminiumCasting



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Salt Casting

DosingMixing

MeltingSalt stock

Salt Core

removal /


Insert Salt

Core

AluminiumCasting

Stock / Quality

Process steps.

Salt core casting out of liquid phase



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Process steps.

Salt core casting out of liquid phase - Movie

Movie



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Salt Core

inlay

Stock / Quality

Salt Casting

Salt Core

removal /


AluminumCasting

DosingMixing

MeltingSalt stock

Process steps.

Aluminum casting with salt core inlay.



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The correct support of the salt core in the die is relevant know-how.

FSISimulation optimises the second phase (filling phase).

Shot is real-time controlled. This is very important in order to avoid

the breaking of the inserted salt core and to guarantee ahigh

reproducibiltiy of the shot.

Process steps.

Aluminum casting with salt core inlay.



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DosingMixing

MeltingSalt stock

Salt Core

inlay

AluminiumCasting

Salt Core

removal /


Salt Casting

Stock / Quality

Process steps.

Removing of salt core



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100% removing of salt.

No damage of the aluminum part.

Low cycle time.

Energy and resource saving.

Requirements for a core-removing unit:

Cut through the aluminium part after removing the salt core

Process steps.




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Different geometries of salt cores

are removable with water-jet:

blind hole.

curved channels.

Examples for removed cores.

Process steps.


Process values:

Removal time 90 sec

Water consumption 30 - 40 l

Water pressure max. 600 bar

Water temperature 20C

Values for 3-cylinder engine block:



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Salt water

Only a little percentage of salt is

dissolved during the removingprocess. Salt content in waterafter removing


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Melting&DosingMixing Salt Core Casting Aluminium Casting Core Removing

Ladleror

dosing furnace

Summary.

Process chain and necessary machines for Lost Core production.



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Thank you.



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Backup



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Why is Bhler developping Lost Core technology?

Existing processes (e.g. Mercury Marine, Yamaha)

were developed only for their own needs.

At the moment there isnt an equipment

manufacturer that is able to provide a

complete solution for industrial process

with high efficiency.

Bhlers focus is to provide the necessary

equipment for the Lost Core technology that

is suitable forindustrial process with high efficiency.



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Patents

With our patents we protect the process and the mixture in order to

guarantee the freedom to operate of our customers.

Patent on process for salt core production

Patent on salt mixture

Patent on removal process



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Aluminum Simulation.

Results of FSI Simulation.

Ingate velocity has an influence on core viability.

Intensification pressure may not be applied before the cavity is filled completely.

0

20

40

60

80

100

120

140

0.00E+00

5.00E+06

1.00E+07

1.50E+07

2.00E+07

2.50E+07

3.00E+07

3.50E+07

4.00E+07

4.50E+07

5.00E+07

2.170 2.180 2.190 2.200 2.210 2.220

IngateVelocity[m/s]

MeanIsoStress[Pa]

Filling Time t [s]

Mean Iso Stress @ 0.7 m/s



Ingate Velocity @ 0.7 m/s





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Calculation for cost effectiveness.

Example for cost calculation

Formkosten pro Salzkern 0.41 EUR

Giesskosten pro Salzkern 1.20 EUR

Material- und Schmelzkosten pro Salzkern 0.49 EURKosten pro Salzkern 2.10 EUR

1. Casting of salt cores

2. Overcasting with aluminium

Cost calculation done by the customer. Comparable to standard DC with inserts.

3. Core removing

Werkzeugkosten pro Salzkern 0.18 EUR

Entkernungskosten pro Salzkern 0.71 EURWasserverbrauchkosten pro Kern 0.11 EUR

Sondermll Entsorgungskosten pro Kern (0.7kg) 0.22 EUR

Kosten pro Entkernung 1.22 EUR



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Calculation for cost effectiveness.

To ensure market penetration the salt core technology has to have

lower process costs than alternative process (e.g. gravity casting with

sand cores).

We calculated the process costs of different parts. The cost

effectiveness is promising.

Water outlet in gravity casting with sand core Water outlet in HPDC with salt core



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Technology substitut ions or fully new parts.

permanent mold.

sand casting.

Process substitutionApplication on

existing technologiesNew parts

Lost Core

low pressuredie casting.

permanent mold.

injection molding.

Vision.


Lost Core Neue Perspektiven Im Druckguss Dario Pierri Buhler Ag

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