Appendix B

Process- Engineering

LTC Casting

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LTC (Low Temperature Die Casting)

Benefit - Reduction of cycle time due to shorter solidification time

- Reduction of cycle time due to less spray time

- Increasing utilization ratio, due to less flash in the die and core slides

- Increasing the die life, due to less erosion and reduced thermal

shock in the cavitiy and shot sleeve

- Monitoring of reduced energy and storing in the “trend data”

- At least same or better part quality

Project Increasing the economical efficiency of standard die casting, working

with an LTC Process using the standard alloy 226 (380)

LTC Process Low Temperature Die Casting: casting with reduced melt temperature,

whereby the temperature is set / adjusted between dosing furnace and

shot sleeve.

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go / no go

Stand Alone

- Bühler Dataspeed M/c

- Older Bühler M/c

- Competitor machines

Integrated

Dat@net

LTC Casting

Controller concept

Product: Production- Optimization

1. Milestone

Identify current situation

2. Milestone

Production analysis

3. Milestone

Licence for the equipment,

Soft- and hardware setup,

1 week production optimization, on site

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Energy balance

! Energy balance between casting temperatures 650°C and ejected part with expected 400°C temperature

! Energy equation between standard production and LTC production

Actual production

LTC Casting

Expected

ejected temperatures

reduced energy

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Product

! Installation of hardware between dosing furnace and casting machine

! Die filling with reduced melt energy content

- The launder is modified into a cooling slope

- Energy removal by using cooling water

- Visualization and storing of the reduced energy

! process optimization

Controlled energy

removal from the

aluminum

Data logging

! Delta T cooling water

! Flow rate cooling water

Prerequisites

! Cooling water min. 20l/min

! Cooling water pressure min. 4bar

Additional

! 2 cooling circles

! (additional +3 cooling circles for

additional data logging (plunger, …)

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LTC - equipment

! LTC Data logging as with Buhltemp

- Collect data from water temperature T1 und temperature T2

- Collect data of flow rate

- Calculating of removed energy content

LTC

! Integrated controller ! Stand Alone ! Software

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Why not just reducing the furnace temperature ?

Disadvantages of a too low furnace temperature

" formation of segregation

" sedimentation

" solidification at critical regions

*

* Giesserei 62

development of LTC

furn

ace

ho

ldin

g t

em

pe

ratu

re

segregation factor SF = (Fe) + 2 (Mn ) + 3 (Cr)

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Case Story

Part

! Production of an oil pan with standard alloy 226 (380), shot weight 8kg

! Volume / surface area ratio V/O = 0.32 (part including runner system)

! Requirement of part quality: High pressure section up to 6.2 bar after machining and

assembling

! Scrap rate between 6 and 10%

Services

! Implementing of LTC Casting

! Additional Optimization at the die design

! Optimization of Spray process at the hot spot section

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Case Story

! Temperature reduction at the die surface (10 to 20°C)

! Increasing die life

! Less Flash

31.0°C

240.0°C

50

100

150

200

SP01

31.0°C

240.0°C

50

100

150

200

SP01

Label Value

IR : max 223.2°C

SP01 223.1°C

Label Value

IR : max 210.6°C

SP01 209.7°C

Standard production LTC production

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Case Story: Results

Benefits Values Description

! Cycle time reduction: before 72s # LTC

new 70s (2.9%) Reduction of solidification time

! Operational availability: up to 8% # LTC

less flash in the die

lower surface temperature

! Die lifetime not determined # LTC

reduce surface temperature

! Production efficiency : before 218‘000 parts # Cycle time reduction & availability

new 250‘600 parts Improvements for the annual production

Production Efficiency

Standard Production

LTC Production

0 50000 100000 150000 200000 250000 300000parts

14.8% Earning

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LTC – Casting

„Welcome to PRODUCTIVITY.“

LTC…..your opinion ?