The Journal of The Institute of Cast Metals Engineers

Foundryman

TRADE JOURNAL
Volume 189 No. 3722   March 2015

Specialists in the Design & Manufacture ofall types of Moulding & Reclamation Plants
and Material Handling Equipment

FTL FOUNDRY EQUIPMENT LTD
6-11 Riley Street, Willenhall
West Midlands, WV13 1RH, UK
T: +44 (0) 1902 630222
E: sales@ftl-foundry.co.uk
W: www-ftl-foundry.co.uk

MOULD & CORE MAKING

As part of an established international design
service, ASK Chemicals is focusing intensively on
the topic of simulating foundry processes. This
involves using predominantly well-known software
solutions, such as Magma, Flow-3D, Arena-Flow®
and Novacast. The company has thus gained agreat deal of experience over several years, both in
the area of simulating casting and solidificationand in the area of simulating core shooting. The
following article provides an overview of thepotential that core shooting simulation offers.
Not only does global competition demand ever-improving
quality with shorter development and production times atlower costs from companies; the constant upgrade of anincreasingly diverse product range is the rule nowadays andpresents a challenge to the caster that is just as great. In thissituation, computer programs, such as simulation software,
can help lower costs, reduce development times and design
optimised stable processes. This is not a new insight, as thispractice has been mastered in the casting and solidification
area for years.
While the development process from the idea toproduction led in the past from the drawing board via

model construction, test castingand various adjustments to thefinished product, today computeraided design (CAD), simulation,
computer-aided manufacturing(CAM) and prototyping are used. In
brief, we speak of computer-aidedengineering (CAE). With regard
to model construction and also,
specifically, the development anddesign of casting systems, this has
certainly been the case for someyears now. We are all familiar withthe advantages and possibilities thatsimulation methods offer in thiscontext.

CORE PRODUCTION
However, the simulation of coreproduction is still considered tobe relatively new. But do we needthis type of simulation? Surely,
nobody knows more about their corebusiness, i.e. their core production,
than experienced casters themselves.
Nevertheless, we must ask ourselves

if this is true. Do we really knowwhat happens and whether we havedesigned the most optimum set-up?
You could almost say that thissheds light on one of the last darkareas of our casting processes, andthat this helps us to better master our‘core business’.
Two key simulation steps are
distinguished in core shooting
simulation. The first is the simulationof the filling process of the core box,
i.e. the actual shooting of the core.
The second is possible or necessary
gassing, i.e. a through-flow of gas
through a cavity of a core box withany type of filling.
The visualisation of the filling
dynamics (fig.1) allows us to makeprecise predictions of areas withhighly diverse degrees of compaction(fig.2).
Conclusions about areas withincreased tool wear can also bedrawn, or predictions can be madefor areas in which an increased
level of binder application can beexpected. (fig.3).
The simulation software ArenaFlow® is the only software on themarket that can depict the actualinteraction between particles (sandCore Shooting Simulation – to theECONOMIC AND ENVIRONMENTALADVANTAGE of the Foundry

Christof Nowaczyk,
product manager for design
service Europe & Asia,
ASK Chemicals, Germany

Fig.1 Visualisation of the filling dynamics

Fig.2 Areas with highly diverse compaction

Fig.3 Tool wear - Kinetic energy x impact angle

Fig.4 Crankcase water jacket with a poorly compacted area
between cylinders 2 and 344

grains are particles) and the flow
medium (air) in a realistic manner.
It can depict problem areas withinsufficient compaction very clearly(fig.4).
The compaction problem
illustrated here is caused by a venting
situation that is not ideal.
This example also clearly showsthat the filling dynamics or the filling
behaviour depends primarily on
the flow conditions of the air in acore box. This flow behaviour canbe illustrated by flow vectors andshows very clearly where insufficientcompaction or problems with gassing
can be expected.
In fig.5, areas with insufficient
airflow are shown in dark blue. With

FOUNDRY TRADE JOURNAL March 2015

MOULD & CORE MAKING

Enormous
potential
in terms ofdevelopmentand production
regard to gassing a core, thistype of evaluation by meansof simulation provides aninitial insight into whether theprocess is homogeneous. If thelower box area already displays
poor flow conditions, it can beassumed with certainty that
gassing problems will occur.
In this case, this means thatsignificantly longer gassing
times and unnecessarily
high amine consumption
are accepted in practice as a‘series production status’ ofproduction. We must therefore
speak of inefficient use of theamine here.
The example seen in fig.6
shows how systematic use andan appropriate optimisation of
the set-up can help improve thequality of the core significantly
while simultaneously reducing
the cycle time by approx
28 per cent. In this case, only
the venting set-up has been
optimised.
What are known as familycore boxes are often designed togo with existing core shooting
machines. Production is thenfrequently faced with theproblem that the compaction ofcertain cores or areas of cores isinsufficient, which often leads
to increased cleaning effort oreven considerable rework of
the cast parts. In most cases,
this is caused by the interaction
between the geometry of
the shooting head, which isinstalled, accepted as given andnot considered further, and theactual set-up of the core box
and the arrangement of theshooting nozzles.
Fig.7 shows clearly that theexisting geometry prevents theback left area of the core from

Fig.5 Airflow in a core box

Fig.6 Gassing result - before (left) and after (right)
optimisation

Fig.7 Analysis of the interaction between the shooting head
and the core box

Fig.9 Simulation - pressurised oil duct, third generation AUDI
EA888: Simulation of gassing

Fig.8 Simulation - pressurised oil duct, third generation AUDI
EA888: Shooting nozzle dynamics

being filled completely, since the amount of mould material that can flow through the sand magazine in
the given time is not sufficient.
Such a situation inevitably leads to significant additional costs, which could have been avoided by
performing a corresponding simulation beforehand. Adapting the design of the shooting head would
certainly be the less expensive form of remedial action. In the worst case, however, this could jeopardise
existing timelines and the possible adherence to milestones that determine the project.
A further practical example, based on an oil duct core in a design by Audi AG, shows the potentialthat core shooting simulation offers in terms of saving costs and resources (figs.8 and 9).
As part of a customer project, the task was to check an existing set-up and to optimise it if necessary
before constructing new core boxes. This project was supported and promoted by the foundry itself, andby the client, Audi AG. As an OEM that does not itself operate a foundry in which cores are used, Audi
AG consistently relies on simulation as a means of achieving stable processes, both in the foundry and in
the purchasing companies later on.

SUMMARY
As with any other type of simulation, the simulation of core production, which is known as coreshooting simulation, offers enormous potential in terms of development and production - be it in thecontext of tool development, ensuring that this tool will perform in the most optimum way and as
desired prior to expensive tool production, or be it as an aid for detecting error causes and savings
potential.
The simulation helps to plan, implement and operate stable processes. However, it also helps toimprove cycle times and reduce amine consumption by optimising gassing cycles. This enables anincrease in productivity and a reduction of resource consumption to occur.
In the highly competitive international foundry market, this represents a distinct contribution toincreasing or maintaining competitiveness.
Contact: ASK Chemicals GmbH, Reisholzstrasse 16-18, 40721 Hilden, Germany, Tel:+49 211 711030,
email: info@ask-chemicals.com web: www.ask-chemicals.com

FOUNDRY TRADE JOURNAL March 201545