ELEMENTYour Guide to Foundries in Pakistan

www.pfa.org.pkSpecial Edition 2017

Industrializing Pakistan

MILLAT TRACTORS LIMITED

ththth INTERNATIONAL FOUNDRYINTERNATIONAL FOUNDRY

CONGRESS & EXHIBITIONCONGRESS & EXHIBITION

INTERNATIONAL FOUNDRY

CONGRESS & EXHIBITIONFEB. 15-16, 2O17, Pearl Continental Hotel, Lahore FEB. 15-16, 2O17, Pearl Continental Hotel, Lahore FEB. 15-16, 2O17, Pearl Continental Hotel, Lahore

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I welcome all the participants to the 6th International Foundry Congress &

Exhibition (IFCE-2017) on 15th-16th February, 2017, at Pearl Continental

Hotel Lahore, Pakistan. It is heartening to note the wide participation of

local and international casting producers, machinery manufacturers,

foundry materials suppliers and service providers, and global foundry

technologist from various countries.

Pakistan Foundry Association is honored by the participation of China

Foundry Association for the first time. We acknowledge the presence of

Chinese machinery suppliers, Indian multi nationals, Turkish Companies,

Magmasoft, leading German foundry Software Company, Chukurova

Kimya-Turkish foundry chemicals producers, TCT- German machinery supplier, VoxelJet AG- 3D Printing

solutions for product development, and Saint Gobain – Furnace refractory producers from France.

We are encouraged with the participation and of leading Pakistani foundries and engineering companies

especially Millat Tractors, Bolan Castings, KSB Pumps Pakistan, Qadri Group of Companies, Chenab

Engineering (Pvt.) Ltd., Excel Group, Karachi Shipyard, Pakistan Ordinance Factory (POF), and all

members of PFA.

This year, subject focused seminars and training workshops by the global foundry technologist from

various countries will be held parallel to the exhibition. New foundry technologies will be introduced and

current technical issues will be addressed.

I foresee the foundry simulation software, 3D printing machine and surface treatment solutions are the

future for local foundry industry to produce high quality castings for national and international markets.

I recommend all foundry men, technical entrepreneurs, and heads of various companies, teachers of

technical schools and Universities, and engineers to benefit from the above sessions.

IFCE-2017 is a great opportunity for all foundry businessmen to discuss advancement with their

counterparts and develop joint ventures.

I wish you all a great success in IFCE-2017 and wish you a memorable event.

-0300 8673873

Joint SecretaryPakistan Foundry Association

Different Methods of sg Iron Production

with their Tehnical and Economical

Advantages and Disadvantages

th50 Census of World Casting

Production

3D Printing: Turbocharging Casting

Processes of all Kinds

RASTGAR AIR COMPRESSORS

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Casting Simulation: FAQ and Answers 20

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3

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5

6

7

10

3D Printing: Turbocharging Casting

Processes of All Kinds

Ingo Ederer

CEO, Voxeljet, Germany

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Jhumra Road Nishatabad, Faisalabad, Pakistan

Fax : 0092 41 8752482

E-mail : info@chenabfoundries.com

web : www.chenabfoundries.com

Tel : 0092 41 8751048

0092 41 8751424

0092 41 8751423

Application Details

Based in Stanhope, County Durham, Astrum is a

specialist steel foundry making components and

assemblies for military ghting vehicles, ground

engaging tools for the construction industry and

wear parts for the mining industry. In 2008, due to

rising energy prices, Astrum embarked on a

programme of improving the energy efciency of

its processes.

Mike Hutchinson, operations director at Astrum

explains, One of our key areas of spend is our

compressed air system, which is critical to the

performance of our plant and is fundamental to

our processes for moving sand around the

foundry and for operating industrial equipment.

As part of our programme of improving the energy

efciency of our processes, we looked to replace

existing compressors and approached CompAir

distributor, Air Energy Management to assess our

air requirements.

A i r Ene rgy Managemen t was ab le t o

demonstrate that by looking at the overall

efciency of the existing system, and making sure

it is designed specically for our needs, we could

save a signicant amount of money.

Carbon Trust

To accelerate its investment plans, Astrum

approached the Carbon Trust and was awarded

an interest free loan through its Big Business Ret

scheme, which aims to provide businesses with

zero-cost capital to invest in new high

performance, energy efcient equipment.

CompAir is a world-class organisation, it has

extremely energy efcient air compressors and its

support services are second to none. ' '

Richard Dainton, managing director, Air Energy

Management

Two regulated-speed comressors from Com pAir

have helped Astrum, a steel components

manufacturer, to cut its compressed air energy

costs by more than a half and increase

productivity at its foundry in Country Durham.

Astrum was able to benefit from an interest-free

loan from the Carbon Trust to fund the

installation,

thanks to the high energy efficiency of its new

compressed air system.

Be nets-at-a-glance

Ÿ 50% reduction in compressed air energy

Ÿ costs saving over £80,000 per annum

Ÿ High quality, extra dry air

Ÿ Increased productivity

Ÿ Backup compressor for

Ÿ increased production reliability

Ÿ Hot air ducting saving £1 0,000 per year in

heating costs

Ÿ Number of air receivers reduced from 16 to 3

RASTGAR AIR COMPRESSORS

How a British Foundry Reduced Energy Costs by 50%

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Imtiaz A Rastgar

Hutchinson comments, The Carbon Trust loan

enabled us to install a system that will not only cut

power consumption, but will also improve the

efciency of our business.

The loan will pay for itself within four years

through energy savings alone, and has provided

a cost effective way for us to upgrade crucial

equipment.

Bespoke system

Working alongside Astrum and CompAir, PJr

Energy Management developed a bespoke

system to reduce the demand on compressed air

at the foundry; and replaced old, large

compressors with two more efcient, smaller

CompAir compressors.

The CompAir L75 RS and L 160 RS compressors

both feature regulated-speed technology and are

protected and monitored by a Delcos 3100

electronic control system.

Both compressors are linked to a aw measuring

system, allowing operators to check airow,

allocate costs to different departments and

pinpoint any leakage. In addition to compressors,

CompAir also supplied energy efcient thermal

mass refrigerant and desiccant dryers.

The new system will reduce MrurrB compressed

air energy demand by 1 ,255,000 kWh and save it

over £80,000 per annum.

Additional infonnation

A CompAir L75 RS regulated-speed compressor

is located in a small compressor house at the

foundry and provides air at 7.5 bar to a bore blast

machine for optimum surface quality.

The L75 Ra; regulated-speed drive technology

matches compressor ow to plant demand with

great efdency. This means that the unit produces

the correct volume of air required by the

application at all times. The unit is suitably sized

to serve a second bore blast machine, should it

be needed.

CompAir overhauled an existing compressor to

provide system redundancy. Previously, Mrum

did not have any backup, meaning that if a

compressor stopped working, production would

be brought to a halt.

Hot air venting from the small compressor house

ensures that 80% of the energy lost in the

compression process is reclaimed. The hot air is

ducted into the foundry during winter and out into

the atmosphere in the summer, allowing Mrum to

tum off heaters, saving £1 0,000 per year in diesel

costs.

The second CompAir compressor, an L 160 RS

regulated-speed unit with Delcos 31 00 controller,

is located in one of the main compressor houses.

Working alongside overhauled exist ing

compressors, the unit provides air for the 5,000-

litre main foundry receiver.

Hot air from this compressor room, and exhaust

air from the receiver is again ducted into the

foundry. A control valve ensures that the receiver

can be shut off from the compressor house to

eliminate leakage.

The number of air receivers at the Mrum site has

been reduced from sixteen to just three, thanks to

a more efcient use in the new system.

In addition to the two compressors, CompAir has

also supplied a desiccant dryer, providing the

extra dry air required by a molding machine. The

new system also includes low-pressure drop

piping, and a leak detection programme. A ow

measuring system brings information from all

meters into one control panel, allowing operators

to check airow, allocate costs to different

departments and pinpoint any leakage.

Tel: +92 51 222823, Email: io@rastgar.com,

www.rastgar.com

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mould density and interfacial heat transfer

coefficients). Widely used cast metals (like iron,

steel, aluminium, copper, magnesium and zinc

alloys) and major casting processes (green sand,

investment shell, gravity die, and pressure die)

can be handled by most simulation programs

available today.

2. Which physical phenomena related to

metal casting can be simulated?

There are three major phenomena. The first is

mo l ten me ta l flow ing i n to the mou ld ,

accompanied by falling, splashing, streams

separating, rejoining, and onset of freezing. The

second is metal sol idification, which is

accompanied by changes in volume and

formation of microstructure. The third is metal

cool ing to room temperature, which is

accompanied by stresses and distortion.

Solidification simulation is a mature technology.

Coupled simulation of two or more events is

complex, requires more computation time and is

usually less accurate.

3. Which cas t ing processes and

phenomena can be s imula ted more

accurately?

Gravity casting processes, in which casting

solidification time is much longer than mold filling

time, can be accurately modelled and simulated

since only physical phenomenon (metal

solidification) has to be handled. An example

would be heavy steel castings produced in sand

molds. On the other hand, pressure die casting is

much more difficult to simulate accurately, since it

involves simultaneous multi-physics phenomena

of metal droplet spray at high velocity

instantaneously solidifying against the metal die

walls.

Abstract

A number of simulation programs are available

today to visualize mold filling and casting

solidification. Such virtual trials save the time and

production resources otherwise required for

shop-floor trials. The simulation results provide

the necessary insight to determine the cause of

past defects (hindsight) or prevent future defects

(foresight). The methods design is iteratively

modified and simulated till the desired quality and

yield are achieved. The simulation programs are

also useful for checking the castability of a part

design, early in its lifecycle, when it is easier to

modify and achieve significant cost reduction.

Most of these programs claim to be versatile,

intelligent, accurate, user-friendly and cost-

effective. But many doubts prevail. This

compilation includes the most frequently asked

questions by foundry engineers collected over

the last 20 years, and their answers by experts.

The questions and answers are not specific to

any particular casting simulation program. They

are divided into three parts, each with 15

questions. Part I includes the applications and

benefits; Part II includes user inputs and results;

and Part III includes their selection and optimal

use.

PART I: Applications and Benefits

1. Which casting metals, processes and

phenomenon can be simulated?

In theory, any metal that can be melted and

poured into a mould can be simulated. In practice,

simulation is limited to only those metals and

processes for which relevant data is available.

This includes thermo-physical properties of metal

(like specific heat and viscosity at various

temperatures) and process characteristics (like

Casting Simulation: FAQ and Answers

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Dr. B. Ravi, Institute Chair Professor,

IIT Bombay, Mumbai

4. What are the typical / essential

modules of casting simulation software?

There are three major modules of casting

simulation software. The Pre-processor takes

various inputs from the user, and sub-divides the

entire mould along with casting, into a mesh of

small elements. The Solver computes the

temperature, velocity and other results at each

element as a function of time. The Post-processor

displays the results as colour-coded plots for

visualization. Some casting programs have

modules based on the type of mold or process

(ex. sand, die, or investment casting). These

con ta in p rocess-spec ific var ia t ions o f

mathematical models and material databases.

5. What are the most important results

from casting simulation?

Flow simulation gives the location, velocity and

pressure of molten metal front during mould

filling. Solidification simulation gives the

temperature and cooling rate in all locations

inside the casting and mould. Further simulation

can provide phase distribution, microstructure,

cooling stresses and casting distortion. All these

results are displayed as colour-coded plots at

different instants of time and can be played like a

video animation. The results can usually be

viewed in 3D as well as 2D cross-sections.

6. Which cast ing defects can be

predicted by computer simulation?

Solidification-related defects: shrinkage cavity

and porosity, can be accurately predicted by most

simulation software. This is followed by flow-

related defects: cold shut, misrun and sand

inclusion. Blow hole and gas porosity are difficult

to predict since they depend on a lot more shop-

floor conditions which cannot be captured in

simulation. Cooling-related defects: hot-tear,

distortion and hard-spots can be predicted by a

few simulation software, though with a lower level

of accuracy.

7. Can we improve the quality and yield

of a casting by simulation?

Simulation by itself does not improve casting

quality and yield of a casting, but enables a

casting engineer to virtually try-out different

combinations of methods design and process

parameters to identify the one that gives the

des i r ed qua l i t y w i t h good y i e l d . The

improvements in quality and yield, and the time

taken to achieve them, depend on the experience

of the casting engineer in interpreting the

simulation results, methoding knowledge for

improving the casting design, and understanding

of process capabilities for implementing the same

on the shop-floor.

8. How much time is required for one

simulation run?

The actual computation time (simulation solver)

ranges from a few minutes to several hours,

depending on casting model, type of results, and

computer configuration. Large parts (in terms of

file size) need to be divided into more number of

elements and hence require more computation.

Simulation of only mold filling or only casting

solidification takes less time than coupled

simulation of both phenomena. Some casting

programs allow quick simulation for initial

iterations. Full simulation is carried out only for

the last iteration (usually in night time) for

verification.

9. How many iterations are needed /

possible to optimize quality and yield?

There is no upper limit for the number of iterations

that can be performed using casting simulation

software. In practice, this is limited by the target

(desired quality and yield) and the time available.

Each iteration requires modification of methods

design, which depend on the foundry knowledge

of the engineer. In most cases, acceptable

targets can be achieved within 5-10 iterations of

methods modification and quick simulations

followed by a full (detailed) simulation to verify the

final design. All these can be completed usually

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within a week.

10. Can simulation software create gating

and feeder models?

Most simulation programs expect the users to

create the mould cavity layout with gating and

feeders in a separate 3D CAD program, and

import the entire casting for simulation. Based on

the results, the users have to go back to the CAD

program, make suitable changes, and re-import

the model for simulation. Some simulation

programs include basic solid modeling facilities to

reduce the above hassle. Very few programs

provide integrated design, 3D modeling,

simulation and optimization of methods design.

11. Can simulation software optimize the

gating and feeder designs?

Optimization implies achieving the desired

quality along with high yield by iterations of

simulation, interpretation of results, and

modification of methods design. All of these tasks

require human intervention. Some software

programs provide initial design and models of

gating and feeding, which helps in minimize the

number of iterations. A few others run multiple

simulations driven by user-defined criteria and

range of design parameters, but this can take

several hours for complete results.

12. What are the economic benefits of

casting simulation to a foundry?

The most tangible (measurable) benefit is energy

saving due to improvement in yield and quality,

and increased capacity without adding more

equipment. New casting development time is

usually compressed to one third (from several

weeks to just days), which is important for jobbing

foundries. Production foundries can halve their

total rejections (say, from 8% to 4% overall).

13. What are other (intangible) benefits of

casting simulation to a foundry?

The main intangible benefit is higher customer

satisfaction through better quotes (since yield

can be accurate ly est imated) , qu icker

submission of first good sample casting (by rapid

virtual trials), and consistent quality for

subsequent shipments. Other benefits include

more orders (by projecting the simulation

capabilities of foundry), higher-value orders (by

taking up more difficult projects), and better

employee morale (better output and longer

retention).

14. Why OEMs increasingly insist on a

simulation report along with RFQ?

With Just in Time manufacturing philosophy

adopted by most of the original equipment

manufacturers, the cost of poor quality is much

higher today. Further, new product development

times have also reduced. Hence OEMs need to

be assured that a foundry is capable of quickly

developing a new casting, getting its quality 'right

first time', and also keep the quality consistent

('right every time'). A simulation report is the best

way to ascertain the capability of the foundry, and

is therefore expected along with Request For

Quote for new projects.

15. In what other ways simulation is useful

to OEMs?

Original equipment manufacturers use the

simulation results in many ways to improve

overall quality assurance. Simulation shows

difficult-to-feed areas (isolated hot spots), which

can be either reduced in magnitude, or provided a

feed path and feeder boss to ensure directional

solidification. Such part design changes, carried

out by OEM, can reduce the difference in weight

between the designed part and as-cast part,

which is often a major point of contention

between OEM and casting supplier. The

simulation results can also be used to identify

critical areas that need careful inspection, and

provide useful insights for collaborative solutions

through technical discussions.

PART II: User Inputs and Results

16. What are the major (essential) inputs

required from the user?

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Essential inputs for simulation include the 3D

CAD model of the casting along with gating and

feeders; mould and its elements including

cavities, cores, vents, and feedaids (sleeves,

covers, chills, coatings, etc.); specification of the

corresponding materials, and critical process

parameters (like pouring temperature and rate).

The casting model should include all allowances:

shrinkage, draft, fillets, machining, and distortion.

Any difference between the simulated model and

shop-floor casting will lead to a mismatch

between the virtual and real results.

17. Which default inputs are assumed by

the system, but user can provide own values?

There are many parameters that are required for

simulation and affect the accuracy of results, but

are difficult to input by the users, and hence

default values are assumed by simulation

programs. These include various interfacial heat

transfer coefficients (between metal-mould,

mould-air, metal-air, metal-chill, chill-mould, etc.),

limiting values for stoppage of metal flow and

feeding, various choices of assumptions and

approximations for optimizing computation

speed and accuracy. Since most of these are

neither easily understood nor available with the

users, their values are taken from databases

included with simulation software.

18. What is IHTC (interfacial heat transfer

coefficient)?

The IHTC represents the rate of heat transfer per

unit area per unit time, between a given pair of

materials. It usually accounts for all modes of

heat transfer: conduction, convection and

radiation. The most important IHTC is between

solidifying metal and surrounding mold. It is not

constant; it is high in the beginning, when the

temperature difference is large and the casting-

mold pair are in perfect contact. The IHTC

gradually reduces as the casting temperature

falls, mold temperature rises, and air gap

between them grows. The air gap itself is not

uniform and depends on casting shape.

19. How can we get the correct value of

IHTC (interfacial heat transfer coefficient)?

Simulation software usually provide the default

values of IHTC between important pairs of

materials: casting to mold, casting to chill, mold to

air, etc. The IHTC database contains the values

for different combinations of materials (ductile

iron casting to green sand mold, etc.). If the

values are not available for a particular

combination, then either experiments need to be

conducted by the user, and the data provided to

the software to generate and incorporate the

values in its database.

20. Can simulation programs handle a

new alloy composition provided by user?

Users can select an existing alloy or create a new

entry in the material database of the software,

and edit its composition. However, the thermo-

physical properties of the casting alloy are

required for simulation, and these values too

need to be entered. It is not easy to generate the

property values, since they require expensive

experimental faci l i t ies and experienced

technicians. Some software programs estimate

the property values based on composition, but

these are approximations, and need to be

verified.

21. What is the difference between FDM

and FEM based simulation programs?

FDM stands for Finite Difference Method, in

which the computation domain (casting and

mould) is subdivided into structured (brick)

elements. In Finite Element Method or FEM, the

subdivision uses unstructured elements (like

tetrahedrons). The latter can better approximate

the casting and mould geometry with fewer

elements, and thereby can give more accurate

results, but the mesh generation is usually more

cumbersome and error-prone. Most casting

software programs therefore prefer FDM and its

variations like Finite Volume Method (FVM) and

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Control Volume Method (CVM).

22. Can we use a general-purpose FEM

program for casting simulation?

A general-purpose FEM program can be used for

casting simulation, after incorporating the

relevant mathematical models for metal flow,

casting solidification and further cooling to room

temperature. The necessary databases of

temperature-dependent material properties (like

density, specific heat and thermal conductivity)

and process-dependent parameters (like

interfacial heat transfer coefficients) need to be

created. The program will need to be verified and

validated. All this requires a high level of research

expertise, time and effort, but gives the benefit of

an excellent understanding of casting process

modelling and computer simulation.

23. We only have 2D CAD drawings of

castings. Is it possible to simulate?

Simulation requires a 3D CAD model of the

casting, that too, a solid model (and not a surface

model) implying that all mass properties can be

computed. Any 2D drawings need to be manually

converted into solid models using a 3D CAD

software. Simple parts can be modelled within a

few minutes to an hour. Very complex parts like

gear boxes and engine blocks can take several

days to model, that too, by expert CAD engineers.

Once a 3D CAD model is prepared, it is easy to

store, view, modify and exchange, and to

evaluate using different types of simulation for

function, stress and manufacturing.

24. How can we get 3D CAD models of

castings for simulation?

There are three ways: (i) request the model from

the OEM customer or tool maker, (ii) approach an

engineering service provider, or (iii) create the

model in-house using a suitable CAD software

program. The level of difficulty increases from the

first to the last, but this is compensated by better

control on the output and other uses like design of

methods and tooling elements, inspection

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planning and CNC machining. Some of the model

formats (like .STL) cannot be modified, hence

OEMs are more willing to share these with their

vendors.

25. Can we use a 3D scanner to create the

CAD model of an existing casting?

Several types of contact and non-contact

scanners are available today to create a cloud of

points corresponding to the visible surface of the

casting. These points are then connected to

create the surface and eventually a solid CAD

model of the casting. Internal features, especially

narrow and curved holes cannot be scanned.

Non-contact scanners using white light or laser

are very fast (take only minutes) and fairly

accurate (less than 0.5 mm error).

26. What is the required format of 3D CAD

model file for casting simulation?

Most simulation programs support .STL format

(developed for 3D printing systems) owing to its

simplicity and robustness. An .STL file essentially

comprises (x, y, z) coordinates of the vertices of

triangles completely covering the 3D model, and

the outward pointing normal to those triangles.

Curved surfaces are approximated with flat

facets, leading to an error. This can be minimized

by finer faceting, which can be controlled during

file export. Increasing number of simulation

programs also support other neutral file formats

such as .IGES and .STEP.

27. After simulation, is it possible to

export the casting model to a 3D printer?

A few simulation programs allow iterative

modification, simulation and optimization of

casting models, especially the gating and

feeding. The full model of casting can be saved in

industry-standard formats (like STL or STEP).

This can be exported to a 3D printer for

fabricating the pattern. User has to ensure that

the required draft and allowances have already

been applied to the part model. Some programs

also allow the design of molds and cores, which

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can be printed on 3D sand printers.

28. Do simulation results always match

shop-floor observations?

C o m p u t e r s i m u l a t i o n s a r e b a s e d o n

mathematical models that are approximations of

the real-life. Metal casting process is highly

complex with a large number of parameters and

therefore impossible to simulate accurately. Still,

the results of solidification simulation, such as

shrinkage porosity location are fairly accurate.

Indeed, if the results do not match, one should

check if there are any discrepancies in what is

simulated and what is produced (for example,

size of gate or feeder neck).

29. How can we improve defect prediction

(location and size) by simulation?

Even the best simulation programs cannot

predict the exact location and size of casting

defects, which vary from casting to casting. The

prediction accuracy can be improved by

calibrating the software for a particular metal-

process combination, based on comparison of

simulation results with shop-floor observations

for multiple castings. With more simulations, the

users also gain better knowledge and experience

in interpreting the results, leading to better

predictions.

30. Can computer simulation replace

methoding engineers and shop-floor trials?

The casting simulation programs have come a

long way, and are very useful for quickly exploring

different methoding options for quality and yield

i m p r o v e m e n t w i t h o u t e x p e n s i v e a n d

cumbersome shop-floor trials. But simulation

programs cannot rep lace exper ienced

engineers, who can leverage their past

knowledge to find the best solution in difficult

cases. The results of simulation combined with

the analysis of experienced engineers provide

valuable insight, which is useful to analyse past

mistakes (hindsight), and confidently develop

new castings with minimal shop-floor trials

(foresight).

PART III: Selection and Use

31. How many cas t ing s imula t ion

software programs are available today?

There are more than a dozen commercial casting

simulation programs available today, developed

by vendors from different countries in Asia

(including India), Europe and USA. Given the

complexity and long development time, it is no

surprise that the heart (Solver) of most programs

or ig ina ted in lead ing un ivers i t ies and

Government research labs worldwide, starting in

1980s. Most of the recent improvements carried

out by the respective development teams have

been for improving the graphical user interface

and computational performance.

32. What are the evaluation criteria for

purchasing casting simulation software?

There are three major criteria to evaluate the

suitability of a simulation software for a particular

organization. The first is functionality, which

means that the software specifications should

meet the desired requirements. The second is

usability, which implies that the organization can

indeed get the desired results with the available

human resources. The third is cost effectiveness,

which is measured by the tangible and intangible

benefits against the investments (fixed and

variable costs).

33. How can we evaluate the functionality

of casting simulation software?

The software functionality can be initially checked

by going through its brochure and technical

specifications, industrial case studies, and

feedback of similar customers. Then a

benchmarking exercise should be carried out for

a defect-prone casting produced in the foundry.

Only the casting model and methoding layouts

should be provided; not the defect location for

each layout. Such a blind test will conclusively

prove the accuracy of the simulation software in

predicting the casting quality.

26

34. Are casting simulation programs user-

friendly? How do we know?

Most software programs claim to be user-friendly,

but this can be far from true, especially for foundry

engineers who have little or no previous

experience in CAD and FEM. The best way to

ascertain the usability is to organize a live

demonstration, preferably for one of the problem

castings produced by the foundry. This can give a

clear indication of the types of inputs, decisions,

technical knowledge, and time involved. The

quality of initial training, frequency of use (at least

once every week) and continued technical

support by the software vendor also greatly

contribute to the software usability.

35. What are the costs involved in

establishing a casting simulation facility?

Initial costs include benchmarking exercise and

evaluation, software l icense (annual or

permanent option), computer hardware, and site

preparation (room, furniture, AC). The cost of

training and technical support for one year is

usually built into the initial cost. Major recurring

costs include salary of the simulation engineer,

and maintenance of software and hardware.

Software maintenance costs usually include

minor upgrades, besides technical support over

e-mail and phone.

36. What is the typical ROI for casting

simulation software?

The return on investment for casting simulation

software depends on the initial cost, usage

(number of casting projects per year), order

weight of simulated castings, and reduction in

wastage of production resources. For typical

casting simulation software implemented in a

medium size jobbing or production foundry, the

initial investment can be usually recovered within

a few months. It is often possible to recover the

software cost with a single project involving an

important large order.

37. Why are casting simulation software

very expensive compared to CAD?

Most CAD software programs are based on

standard geometric engines or kernels, and

mainly differ only in terms of their user interface.

Further, the user base of CAD is several millions,

and technical support is relatively easy since

there are a large number of CAD books, trainers,

and other resources. In contrast, casting

simulation software is highly complex, the user

base is tiny, user expectations are high, and

technical support is challenging. As the

awareness and number of casting simulation

users grow, their cost is bound to come down.

38. Should we opt for in-house simulation

facility or outsource to consultants?

In-house simulation facility is usually preferred by

medium and large foundries, who continuously

need to develop new castings, or improve the

quality and yield of many existing castings in

regular product ion. Foundries handl ing

confidential components for aerospace, defence

and other sectors also need to have in-house

simulation facilities. They should have adequate

qualified human resources to design, simulate

and optimize the castings. Small foundries who

do not meet the above criteria can opt for

simulation services offered by consultants.

39. What are the recommended specs of

computer hardware for simulation?

The hardware ranges from laptop and desktop

computers to powerful workstations and

computer clusters. The latter are needed for

simulating coupled physics for complex and

multi-cavity castings. For most castings however,

desktop computers with Intel i5/i7 or equivalent

CPU, 8-16 GB RAM, graphics card, and 100-200

GB of free hard disk space are sufficient for

completing the simulation at reasonable

accuracy within a few hours. Most of the

programs work in 64-bit Windows operating

systems (which allows utilizing more memory),

and support multi-core CPUs (providing better

performance).

40. What is the role and importance of

technical support for casting simulation?

The technical support team is usually responsible

for initial benchmarking (before software

purchase), installation and training (immediately

a f t e r p u r c h a s e ) . T h e y a l s o h a n d l e

troubleshooting in the event of software not

working for any reason, and re-training if any

major upgrades are installed. Since casting

simulation software are technically complex, the

quality and speed of technical support are critical

for successful continued usage and resultant

benefits.

41. Is web or video conferencing suitable

for software training and technical support?

Video conferencing enables multiple training

sessions over a period, which are more effective

than a single long session. It is also very useful for

technical clarifications or troubleshooting advice

at a short notice. There are many free or low-cost

options for web-based video conferencing, if

broad-band Internet is available (at least 1 Mbps).

These allow video, audio, text-chat, and

computer screen sharing, with option for

switching the mouse control between the two

sides. If internet speed is limited, then only screen

sharing option can be used along with a

telephone line for talking.

42. Do we need knowledge of CAD and

FEA to run casting simulation programs?

Older generation simulation programs, especially

those built by customizing a Finite Element

Method code, require a large number of input

parameters to be specified by the users, and this

requires a good knowledge of FEM as well as the

underlying physics. New generation programs

developed with the latest programming

techniques, usually employ better assumptions

and superior user interfaces, making them more

intelligent and intuitive. This reduces the learning

curve, number of user inputs, and time taken.

43. Is prior methoding experience needed

to use simulation software?

For merely running a simulation program, prior

experience in methoding of castings is not

needed. However, such experience is very useful

for correctly interpreting the results of simulation,

matching them with shop-floor observations, and

for improving the methods design before the next

iteration of simulation. Since it takes several

years to gain useful methoding experience, it is

advisable to team up a senior methoding

engineer with a CAD engineer, for effective

utilization of simulation software.

44. How much time does it take to learn

and start using simulation software?

The user interface for various functions, including

inputs and results, can be learnt within one or two

days and practiced over a week. However,

understanding the importance of various

parameters, learning how to interpret different

results, and customizing of software database

can take several weeks to months. This usually

requires comparing the results of different

projects, reading technical literature, and

discussion with experts.

45. How can we reduce the total time for

casting optimization using simulation?

The total time depends on the number of

iterations and time per iteration. The number of

iterations can be reduced by using relevant

knowledge of methoding and prior experience

with similar castings. The time for each iteration

can be reduced by using better computation

hardware (more powerful CPU, higher amount of

computer memory, multi-core and parallel

processing) and using a simulation program that

can leverage the capabilities of high-end

computers.

27

DIFFERENT METHODS OF SG IRON PRODUCTION WITH THEIR

TEHNICAL AND ECONOMICAL ADVANTAGES AND

DISADVANTAGES

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Mr. Mujtaba Ahmad

Foundry Consultant

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