2buhler lost core

1 | © Bühler |

Lost Core

New Perspectives in Die Casting

Dario Pierri, Bühler AG

Lost Core | 2012

2 | © Bühler |

Content

� Short company’s presentation

� Potential of die casting with lost

core technology

� Die casting with lost core as

compared with permanent mold

and sand casting

� Advantages of die casting with

lost core

� Process steps for producing parts

with lost core technology

Lost Core | 2012

3 | © Bühler |

Bühler - A 150-year success storyGlobal leader with strong local roots

� Technology partner for machines,

systems and services for processing

basic foods and for producing

high-quality materials.

� Present in over 140 countries.

� Over 70 sales & service companies, more than

20 manufacturing sites and 24 service stations

around the world.

� Annual sales 2011: € 1,760 million.

� Number of employees: 8,800.

� High innovation rate.

� 100 % family owned.

Lost Core | 2012

4 | © Bühler |

OEM’s requirements for engine block

� Resistant to high pressure and high

temperature due to high charged

engines (downsizing)

� Cost efficiency & low cycle time

� Lightweight

� Design’s freedom for cooling channels

and for necessary reinforcing ribs

Lost Core | 2012

5 | © Bühler |

Lost Core TechnologyNew design opportunities and expanded parts spectrum

Advantages of die casting

with Lost Core

� Complex internal shaping - undercuts

� Integral design: New combinations of

functions and components

� New part design opportunities for die

cast parts (e.g. „Closed-deck“ motors)

Lost Core | 2011

Turbo charger (cold side)

3D-Freiformkanäle-Projekt

6 | © Bühler |

Water outlet

Source: Bocar

Lost Core TechnologyTransferring parts from other casting technologies to die casting

Die casting with Lost Core as compared

with permanent mold and sand casting

� Savings of material due to

thin-walled parts

� Higher degree of productivity due to

shorter cycle times for die casting

� Less machining after casting

Higher cost effectivness by using

Lost Core technology

Lost Core | 2012

7 | © Bühler |

*Source: Bocar Mexico

compared to permanent mold casting

up to 15% cost

advantage*

reduction ofmaterial

(lightweighting)

higherproductivity

less machining

Lost Core TechnologyCustomer’s benefit

Lost Core | 2012

8 | © Bühler |

Process stepsOverview

Salt core produced

out of liquid phase

Aluminium is casted

around the salt cores

Remove

salt cores

Lost Core | 2012

9 | © Bühler |

Process stepsFirst step: salt core produced out of liquid phase

Salt cores production

� Salt cores production process is

similar to standard die casting

process

� Process is full automated

� Salt mixture is optimised for:

- increasing the strength

- minimising the costs

� Thermal optimization of the process

for high quality salt cores

Lost Core | 2012

Casted salt core

10 | © Bühler |

Process stepsSecond step: aluminium is casted around the salt core

� Shot is real-time controlled. This is

very important in order to avoid the

breaking of the inserted salt cores.

� The correct core support is relevant

know-how.

� FSI–Simulation (Fluid Structure

Interaction) optimises the position

between salt core and the casted

aluminium in order to minimize the

impact forces on the salt core.

Lost Core | 2012

Aluminium part with salt core inside

11 | © Bühler |

Process stepsSecond step: aluminium is casted around the salt core

Lost_core_full_aut

omatic_cycle

Lost Core | 2012

12 | © Bühler |

Process stepsThird step: remove salt cores

� Efficient removal process

tremoval < tproduction_salt_core

� Low water consumption

� Low economic impact on process costs

� High recycling rate of salt material

� Only a low percentage of salt is

dissolved in water. Uncritical for

environment as long as pH-value is

below 8

� Process is full automated

Lost Core | 2012

Aluminium part after removing the

salt core

13 | © Bühler |


Seperator water-salt

robot

arm

nozzles

Lost Core | 2012

15 | © Bühler |

Salt Core Simulation.Results of filling simulation.

� Prediction of potential air porosity.

Simulation result shows potential areas for air porosity.

Lost Core | 2012

16 | © Bühler |

Salt Core Simulation.Solidification.

� Prediction of potential shrinkage

porosity.

� Simulation successfully validated by

casting examples.

Lost Core | 2012

17 | © Bühler |

Lost Cores technology meets requirements for engine block

Bühler supports you with:

� the optimal die casting machine

� optimized peripherals

� the necessary process know-how

� Cost efficiency & low cycle time

� Lightweight

� Resistant to high pressure and high temperature due to high charged

engines (downsizing)

� Design’s freedom for cooling channels and for necessary reinforcing

ribs

Lost Core | 2012

19 | © Bühler |

Compare: open/closed deck

Source: VW

Lost Core TechnologyNew design opportunities and expanded parts spectrum

Advantages of die casting

with Lost Core

� Complex internal shaping - undercuts

� Integral design: New combinations of

functions and components

� New part design opportunities for die

cast parts (e.g. „Closed-deck“ motors)

Innovative approaches for die casting

Lost Core | 2012

20 | © Bühler |

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

Ing

ate

Velo

cit

y[m

/s]

Mean

Iso

Str

ess [

Pa]

Filling Time t [s]

Mean Iso Stress @ 0.7 m/s



Ingate Velocity @ 0.7 m/s



critical stress

Lost Core | 2012

2buhler lost core

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