Description
Casting is a method for creating one or more copies of an original piece of sculptural (three-dimensional) artwork.
Process Flow for the Production of
Casting
CASTING
Casting is a method for creating one or more copies of an original piece of sculptural
(three-dimensional) artwork. Casting is a manufacturing process, in which we pour
molten metal in the pre-made mould; mould may be of sand or of metal, and let it be
solidified. After solidification and removal of the mould the metal takes the desired
shape. Four main elements are required in the process of casting pattern, mold, cores, and
the part. The pattern, the original template from which the mold is prepared, creates a
corresponding cavity in the casting material. Cores are used to produce tunnels or holes
in the finished mold, and the part is the final output of the process.
SAND CASTING
Sand casting, which in a general sense involves the forming of a casting mold with sand,
includes conventional sand casting and evaporative pattern (lost-foam) casting. In sand
casting, re-usable, permanent patterns are used to make the sand moulds. The preparation
and the bonding of this sand mould are the critical step and very often are the rate-
controlling step of this process. Two main routes are used for bonding the sand moulds:
The "green sand" consists of mixtures of sand, clay and moisture.
The "dry sand" consists of sand and synthetic binders cured thermally or
chemically.
In conventional sand casting, the mold is formed around a pattern by ramming sand,
mixed with the proper bonding agent, onto the pattern. Then the pattern is removed,
leaving a cavity in the shape of the casting to be made. If the casting is to have internal
cavities or undercuts, sand cores are used to make them. Molten metal is poured into the
mold, and after it has solidified the mold is broken to remove the casting. In making
molds and cores, various agents can be used for bonding the sand. The agent most often
used is a mixture of clay and water.
Casting quality is determined to a large extent by foundry technique. Proper metal-
handling practice is necessary for obtaining sound castings. Complex castings with
varying wall thickness will be sound only if proper techniques are used.
DESIGN
The first production step for all castings takes place in the design office where ideas are
converted into manufacturing drawings which guide the production team to create the
solid metal end products. Designers need a wealth of information before they reach for
their set squares. The specified shape and size of the final product is obviously needed
but with metal casting the designers needs to know what stresses and conditions the
products will have to withstand so that the correct metal can be chosen. They will need to
know how many castings are needed. All these factors dictate which molding techniques
to choose.
PATTERN MAKING
Once the customer and the rest of the production team have approved the design, a
pattern or model is made. This can be produced in wood, metal or plastic or from a
combination of all three. Patterns must be precise in their shape and finish, for any
mistakes are reproduced in the moulds which are made from them and from which the
final castings are formed. They must be made to allow for the shrinkage of the metal
when it cools and they can include channels to allow metal to flow into the casting shape.
From the initial pattern a prototype or production sample is usually made with which the
customer can experiment to ensure that the final casting will be exactly as required.
MOULD MAKING
The next manufacturing step is moulding in which the pattern is packed in a moulding
material, usually some type of sand, and then removed to leave the right shape for the
casting. Moulds can be made by hand, or machine. In one casting process the mould is
made from a heat resistant metal. Moulds are usually made in at least two parts and for
very large castings they may even start out as large holes dug into the sand floor of the
foundry. Different types of sand are used for moulding with additives like water and clay
and various chemicals, depending on the size of the mould and the types of metal that are
being cast. One important feature of the mould is the running system which is a network
of small channels that leads the molten metal down into the casting shape. The shapes
and sizes of these channels have to be carefully calculated to ensure that the molten metal
does not solidify before it gets to the casting shape and to make sure that it does not flow
too fast when it could wear away the mould. Many castings are designed to have cavities
in them – engine blocks, for example. These voids, which have to be as accurate as the
outer moulds, are made by forming their shape in moulding material. The shapes, or
cores as they are known, are placed in the mould and after the molten metal has
solidified, the core material is removed leaving a precisely shaped cavity behind.
For mould preparation as per production plan a mixture of sand charge which contains
system sand, new sand, bentonite, CL4 and dextrin is collected in the bucket. The bucket
is raised and the sand is unloaded into the muller. Sand is mixed for two minutes in dry
condition with 5-15 liters of water in the muller. Next the sand is mixed for three minutes
in wet condition. After this process is completed the sand sample is measured and once
the sample is qualified as per the required standards the mixture is dropped into the
hopper.
MACHINE MOULDING
To make green sand moulds on the machine.
1. Take inspected pattern and moulding pins from pattern shop
2. Fit pattern on machine with moulding pins and clean the pattern with diesel spray
and plumbago powder.
3. Place first box on match plate and sieve on it. Take some initial system sand and
sieve it through sieve. Remove sieve.
4. Fill the half box with system sand and jolt. Place the spruce cup on position (for top
box moulding only).
5. Do jolting and ram the sand with pneumatic hand rammer.
6. Fill full box with sand and jolt. Squeeze the sand and do simultaneous jolting.
7. Remove spruce cup from top box and do random venting.
8. Lift the box with lifting rods and remove it from machine with electrical hoist.
9. Before keeping bottom box on pallet, clean pallets thoroughly. Clean the bottom
box mould with air. Place the stained core as specified and cores for cored items.
10. Make proper venting for top box, clean it with air and close the box.
11. Insert the closing pins into box bushes.
12. Mark the box with heat number and serial number with chalk. Move the box for
pouring.
HAND MOULDING
To make green sand moulds and CO2 sand moulds manually.
a) Green sand hand moulding
1. Take inspected pattern, propagating system for loose patterns and moulding pins
from pattern shop.
2. Select proper sized boxes and moulding pins.
3. Place pattern on ground and box on it. Clean the pattern with air and apply diesel
and plumbago powder.
4. Cover the patter with green sand mix upto 30-40 mm approximately an dram it
properly.
5. Cover this sand with baking sand and ram it properly till box fills completely.
6. Make proper venting and scrape the surface to remove access sand if any.
7. Repeat the procedure for top box moulding. For loose pattern moulding turn the
bottom box moulded with pattern and then mould the top box on it.
8. Remove pattern from mould.
9. Close the boxes for pouring.
b) CO2 sand moulding
1. Take inspected pattern, propagating system for loose patterns and moulding pins
from pattern shop.
2. Select proper sized boxes and moulding pins.
3. Place pattern on ground and box on it. Clean the pattern with air and apply diesel
and plumbago powder.
4. Cover the patter with green sand mix upto 30-40 mm approximately and dram it
properly.
5. Cover this sand with baking sand and ram it properly till box fills completely.
6. Make proper venting and scrape the surface to remove access sand if any.
7. Pass CO2 gas through the vents for half minute approximately per vent.
8. Repeat the procedure for top box moulding. For loose pattern moulding, turn the
bottom box moulded with pattern and then mould the top box on it.
9. Remove pattern from mould.
10. Paint the moulds with spirit paint by spraying.
11. Heat the moulds with diesel or LPG burners.
12. After cooling close the boxes.
CORE MAKING
Good core making begins with high quality core sand preparation. The preparation of
cores from sand mixer consists of the following procedure
Preparation of sand mix for core making on compax machine:
Take 20 kgs. of dry sand of AFS number 50-55. Add 0.2 to 0.25 kg of Resin and mix
manually for 2-3 minutes. Add 0.2 to 0.25 kg. of binder and mix manually for 3-4
minutes. Feed the sand into hopper.
Preparation of sand mix for oil and CO2 core making:
Oil sand core: Take 140 kgs. of new sand of AFS number 60-65 in sand muller. Add 4.5
to 5 liters of core oil and mix it for 6 minutes. Add 4.5 to 5 kgs. of dextrin. 2.5 to 3 kgs.
of Bentonite and mix for 6 minutes. Add 0.5 to 1.5 liters of water in sand and mix for 3
minutes.
CO2 sand core: Take 140 kgs. of dry sand of AFS number 50-55. Add 10 kgs. of sodium
silicate and mix it for 12 minutes.
Preparation of cold box cores on compax machine:
Take the inspected core boxes from pattern shop. Install the core box on the machine with
proper fittings. Operate the cycle from control panel. Take out the core from the machine.
The core hardness should be 5% with scratch hardness tester, within 75 to 95.
To prepare CO2 and oil sand cores from sand mix:
a) Oil sand core:
1. Take the inspected core box from pattern shop.
2. Take the sand mix.
3. Fill core box with sand mix and ram with wooden rammer.
4. After ramming scrap the excess sand from top surface.
5. Make the proper venting in core.
6. Remove the core from core box and keep them batch wise.
7. Heat the cores batch wise in oven to remove moisture.
8. Paint the cores with spirit paint if applicable.
b) CO2 sand core:
1. Take the inspected core box from pattern shop.
2. Take the sand mix.
3. Fill core box with sand mix and ram with wooden rammer.
4. After ramming scrap the excess sand from top surface.
5. Make the proper venting in core.
6. Pass the CO2 gas from the vents for half minute per vent.
7. Remove the core from core box and keep them batch wise.
8. Paint the cores with spirit paint by spray painting.
9. Heat the cores with the help of diesel/ LPG burner.
MELTING and POURING
To operate the furnace for MELTING metal:
1. Switch on the power supply to the furnace.
2. Take the furnace charge as per the charge sheet and melt it in furnace.
3. Slowly increase the power supply to full rating. Add the alloys into furnace as per
charge sheet for alloy addition add CI boring about 25-30 kgs. if available.
4. Spread slag power over molten metal surface and remove slag.
5. Pour the sample in CE cup for checking C and Si %.
6. Pour one sample in die for spectrometer analysis
7. Pour one chill before inoculation and another after inoculation.
8. Spread slag powder over molten metal surface and remove slag.
9. Mg. treatment for SG iron: add 5.5 kgs. of FeSiMg and 2-3 kgs. CRC punching at
the bottom of treatment ladle. Place cover and clamp it. Pour the metal.
POURING
There are two ways of pouring metal. Manually pouring and poring with the help of
ladle. To prepare ladle for pouring scrap clean the ladle completely. Take silicate 10
kgs., sand 140 kgs. and Bentonite 1 kg. Apply thin layer of sodium silicate from inside
ladle. Make the lining of sand approximately 25 mm. with flat wooden rammer. Make
spout of 25-30 mm on one side. Make spout mouth at the bottom 40-50 mm in length, 15-
20 mm in width. Spray sprit paint on lining. Heat the ladle with diesel or LPG burner to
remove moisture.
SHOT BLASTING, FETTLING & PAINTING:
Shot blasting: Load the castings on hanger 300 to 350 kgs. push the hanger inside the
machine and close the door tightly. Start the machine and timer. After time is over, pull
the hanger out from the machine. Remove castings and hand over to fettling.
Fettling: Remove all the excess material from castings by chipping and grinding.
Painting: Apply rust preventive polymer paint to the non-machining areas of the casting.
In today's competitive market, you can't afford to miss the savings and technical
advantages from reclamation.
Modern foundries demand optimized control over molding sand preparation in order to
minimize costs and maximize the performance of the molding sand preparation system.
Tightly controlled sand properties allow for low-defect, high-quality mold and casting
production. For optimal performance, molding sand control must begin long before final
mulling. Molding sand at shakeout can have wide variations in temperature, moisture
content, and physical properties. Hot sand leads to casting scrap, mixing inefficiency,
material handling and environmental problems. Precise control over final sand
preparation demands that between shakeout and final mulling, the return sand is lowered
in temperature and homogenized.
Sand is the largest foundry process waste, typically constituting about 70% of total waste
volume. Fortunately, most foundry sands are reclaimable and can be effectively reused.
The basic reasons for reclaiming sand
It's Cost Saving: The costs of molding and core sand continue to increase significantly
and cut into foundry profitability. To lower the cost of producing a casting foundries
desire to reduce total sand cost which includes the purchase cost, delivery cost,
unloading, storing, handling and disposal costs including, in some instances, ever more
expensive landfill fees.
It's Environmentally Responsible: Environmentally, it's becoming increasingly more
difficult to dispose of great quantities of waste sand into a landfill.
It Has Technical Advantages: Technically, reclamation is of interest because many
foundries report that better castings can be made at lower costs, from reclaimed sand.
doc_682970187.docx
Casting is a method for creating one or more copies of an original piece of sculptural (three-dimensional) artwork.
Process Flow for the Production of
Casting
CASTING
Casting is a method for creating one or more copies of an original piece of sculptural
(three-dimensional) artwork. Casting is a manufacturing process, in which we pour
molten metal in the pre-made mould; mould may be of sand or of metal, and let it be
solidified. After solidification and removal of the mould the metal takes the desired
shape. Four main elements are required in the process of casting pattern, mold, cores, and
the part. The pattern, the original template from which the mold is prepared, creates a
corresponding cavity in the casting material. Cores are used to produce tunnels or holes
in the finished mold, and the part is the final output of the process.
SAND CASTING
Sand casting, which in a general sense involves the forming of a casting mold with sand,
includes conventional sand casting and evaporative pattern (lost-foam) casting. In sand
casting, re-usable, permanent patterns are used to make the sand moulds. The preparation
and the bonding of this sand mould are the critical step and very often are the rate-
controlling step of this process. Two main routes are used for bonding the sand moulds:
The "green sand" consists of mixtures of sand, clay and moisture.
The "dry sand" consists of sand and synthetic binders cured thermally or
chemically.
In conventional sand casting, the mold is formed around a pattern by ramming sand,
mixed with the proper bonding agent, onto the pattern. Then the pattern is removed,
leaving a cavity in the shape of the casting to be made. If the casting is to have internal
cavities or undercuts, sand cores are used to make them. Molten metal is poured into the
mold, and after it has solidified the mold is broken to remove the casting. In making
molds and cores, various agents can be used for bonding the sand. The agent most often
used is a mixture of clay and water.
Casting quality is determined to a large extent by foundry technique. Proper metal-
handling practice is necessary for obtaining sound castings. Complex castings with
varying wall thickness will be sound only if proper techniques are used.
DESIGN
The first production step for all castings takes place in the design office where ideas are
converted into manufacturing drawings which guide the production team to create the
solid metal end products. Designers need a wealth of information before they reach for
their set squares. The specified shape and size of the final product is obviously needed
but with metal casting the designers needs to know what stresses and conditions the
products will have to withstand so that the correct metal can be chosen. They will need to
know how many castings are needed. All these factors dictate which molding techniques
to choose.
PATTERN MAKING
Once the customer and the rest of the production team have approved the design, a
pattern or model is made. This can be produced in wood, metal or plastic or from a
combination of all three. Patterns must be precise in their shape and finish, for any
mistakes are reproduced in the moulds which are made from them and from which the
final castings are formed. They must be made to allow for the shrinkage of the metal
when it cools and they can include channels to allow metal to flow into the casting shape.
From the initial pattern a prototype or production sample is usually made with which the
customer can experiment to ensure that the final casting will be exactly as required.
MOULD MAKING
The next manufacturing step is moulding in which the pattern is packed in a moulding
material, usually some type of sand, and then removed to leave the right shape for the
casting. Moulds can be made by hand, or machine. In one casting process the mould is
made from a heat resistant metal. Moulds are usually made in at least two parts and for
very large castings they may even start out as large holes dug into the sand floor of the
foundry. Different types of sand are used for moulding with additives like water and clay
and various chemicals, depending on the size of the mould and the types of metal that are
being cast. One important feature of the mould is the running system which is a network
of small channels that leads the molten metal down into the casting shape. The shapes
and sizes of these channels have to be carefully calculated to ensure that the molten metal
does not solidify before it gets to the casting shape and to make sure that it does not flow
too fast when it could wear away the mould. Many castings are designed to have cavities
in them – engine blocks, for example. These voids, which have to be as accurate as the
outer moulds, are made by forming their shape in moulding material. The shapes, or
cores as they are known, are placed in the mould and after the molten metal has
solidified, the core material is removed leaving a precisely shaped cavity behind.
For mould preparation as per production plan a mixture of sand charge which contains
system sand, new sand, bentonite, CL4 and dextrin is collected in the bucket. The bucket
is raised and the sand is unloaded into the muller. Sand is mixed for two minutes in dry
condition with 5-15 liters of water in the muller. Next the sand is mixed for three minutes
in wet condition. After this process is completed the sand sample is measured and once
the sample is qualified as per the required standards the mixture is dropped into the
hopper.
MACHINE MOULDING
To make green sand moulds on the machine.
1. Take inspected pattern and moulding pins from pattern shop
2. Fit pattern on machine with moulding pins and clean the pattern with diesel spray
and plumbago powder.
3. Place first box on match plate and sieve on it. Take some initial system sand and
sieve it through sieve. Remove sieve.
4. Fill the half box with system sand and jolt. Place the spruce cup on position (for top
box moulding only).
5. Do jolting and ram the sand with pneumatic hand rammer.
6. Fill full box with sand and jolt. Squeeze the sand and do simultaneous jolting.
7. Remove spruce cup from top box and do random venting.
8. Lift the box with lifting rods and remove it from machine with electrical hoist.
9. Before keeping bottom box on pallet, clean pallets thoroughly. Clean the bottom
box mould with air. Place the stained core as specified and cores for cored items.
10. Make proper venting for top box, clean it with air and close the box.
11. Insert the closing pins into box bushes.
12. Mark the box with heat number and serial number with chalk. Move the box for
pouring.
HAND MOULDING
To make green sand moulds and CO2 sand moulds manually.
a) Green sand hand moulding
1. Take inspected pattern, propagating system for loose patterns and moulding pins
from pattern shop.
2. Select proper sized boxes and moulding pins.
3. Place pattern on ground and box on it. Clean the pattern with air and apply diesel
and plumbago powder.
4. Cover the patter with green sand mix upto 30-40 mm approximately an dram it
properly.
5. Cover this sand with baking sand and ram it properly till box fills completely.
6. Make proper venting and scrape the surface to remove access sand if any.
7. Repeat the procedure for top box moulding. For loose pattern moulding turn the
bottom box moulded with pattern and then mould the top box on it.
8. Remove pattern from mould.
9. Close the boxes for pouring.
b) CO2 sand moulding
1. Take inspected pattern, propagating system for loose patterns and moulding pins
from pattern shop.
2. Select proper sized boxes and moulding pins.
3. Place pattern on ground and box on it. Clean the pattern with air and apply diesel
and plumbago powder.
4. Cover the patter with green sand mix upto 30-40 mm approximately and dram it
properly.
5. Cover this sand with baking sand and ram it properly till box fills completely.
6. Make proper venting and scrape the surface to remove access sand if any.
7. Pass CO2 gas through the vents for half minute approximately per vent.
8. Repeat the procedure for top box moulding. For loose pattern moulding, turn the
bottom box moulded with pattern and then mould the top box on it.
9. Remove pattern from mould.
10. Paint the moulds with spirit paint by spraying.
11. Heat the moulds with diesel or LPG burners.
12. After cooling close the boxes.
CORE MAKING
Good core making begins with high quality core sand preparation. The preparation of
cores from sand mixer consists of the following procedure
Preparation of sand mix for core making on compax machine:
Take 20 kgs. of dry sand of AFS number 50-55. Add 0.2 to 0.25 kg of Resin and mix
manually for 2-3 minutes. Add 0.2 to 0.25 kg. of binder and mix manually for 3-4
minutes. Feed the sand into hopper.
Preparation of sand mix for oil and CO2 core making:
Oil sand core: Take 140 kgs. of new sand of AFS number 60-65 in sand muller. Add 4.5
to 5 liters of core oil and mix it for 6 minutes. Add 4.5 to 5 kgs. of dextrin. 2.5 to 3 kgs.
of Bentonite and mix for 6 minutes. Add 0.5 to 1.5 liters of water in sand and mix for 3
minutes.
CO2 sand core: Take 140 kgs. of dry sand of AFS number 50-55. Add 10 kgs. of sodium
silicate and mix it for 12 minutes.
Preparation of cold box cores on compax machine:
Take the inspected core boxes from pattern shop. Install the core box on the machine with
proper fittings. Operate the cycle from control panel. Take out the core from the machine.
The core hardness should be 5% with scratch hardness tester, within 75 to 95.
To prepare CO2 and oil sand cores from sand mix:
a) Oil sand core:
1. Take the inspected core box from pattern shop.
2. Take the sand mix.
3. Fill core box with sand mix and ram with wooden rammer.
4. After ramming scrap the excess sand from top surface.
5. Make the proper venting in core.
6. Remove the core from core box and keep them batch wise.
7. Heat the cores batch wise in oven to remove moisture.
8. Paint the cores with spirit paint if applicable.
b) CO2 sand core:
1. Take the inspected core box from pattern shop.
2. Take the sand mix.
3. Fill core box with sand mix and ram with wooden rammer.
4. After ramming scrap the excess sand from top surface.
5. Make the proper venting in core.
6. Pass the CO2 gas from the vents for half minute per vent.
7. Remove the core from core box and keep them batch wise.
8. Paint the cores with spirit paint by spray painting.
9. Heat the cores with the help of diesel/ LPG burner.
MELTING and POURING
To operate the furnace for MELTING metal:
1. Switch on the power supply to the furnace.
2. Take the furnace charge as per the charge sheet and melt it in furnace.
3. Slowly increase the power supply to full rating. Add the alloys into furnace as per
charge sheet for alloy addition add CI boring about 25-30 kgs. if available.
4. Spread slag power over molten metal surface and remove slag.
5. Pour the sample in CE cup for checking C and Si %.
6. Pour one sample in die for spectrometer analysis
7. Pour one chill before inoculation and another after inoculation.
8. Spread slag powder over molten metal surface and remove slag.
9. Mg. treatment for SG iron: add 5.5 kgs. of FeSiMg and 2-3 kgs. CRC punching at
the bottom of treatment ladle. Place cover and clamp it. Pour the metal.
POURING
There are two ways of pouring metal. Manually pouring and poring with the help of
ladle. To prepare ladle for pouring scrap clean the ladle completely. Take silicate 10
kgs., sand 140 kgs. and Bentonite 1 kg. Apply thin layer of sodium silicate from inside
ladle. Make the lining of sand approximately 25 mm. with flat wooden rammer. Make
spout of 25-30 mm on one side. Make spout mouth at the bottom 40-50 mm in length, 15-
20 mm in width. Spray sprit paint on lining. Heat the ladle with diesel or LPG burner to
remove moisture.
SHOT BLASTING, FETTLING & PAINTING:
Shot blasting: Load the castings on hanger 300 to 350 kgs. push the hanger inside the
machine and close the door tightly. Start the machine and timer. After time is over, pull
the hanger out from the machine. Remove castings and hand over to fettling.
Fettling: Remove all the excess material from castings by chipping and grinding.
Painting: Apply rust preventive polymer paint to the non-machining areas of the casting.
In today's competitive market, you can't afford to miss the savings and technical
advantages from reclamation.
Modern foundries demand optimized control over molding sand preparation in order to
minimize costs and maximize the performance of the molding sand preparation system.
Tightly controlled sand properties allow for low-defect, high-quality mold and casting
production. For optimal performance, molding sand control must begin long before final
mulling. Molding sand at shakeout can have wide variations in temperature, moisture
content, and physical properties. Hot sand leads to casting scrap, mixing inefficiency,
material handling and environmental problems. Precise control over final sand
preparation demands that between shakeout and final mulling, the return sand is lowered
in temperature and homogenized.
Sand is the largest foundry process waste, typically constituting about 70% of total waste
volume. Fortunately, most foundry sands are reclaimable and can be effectively reused.
The basic reasons for reclaiming sand
It's Cost Saving: The costs of molding and core sand continue to increase significantly
and cut into foundry profitability. To lower the cost of producing a casting foundries
desire to reduce total sand cost which includes the purchase cost, delivery cost,
unloading, storing, handling and disposal costs including, in some instances, ever more
expensive landfill fees.
It's Environmentally Responsible: Environmentally, it's becoming increasingly more
difficult to dispose of great quantities of waste sand into a landfill.
It Has Technical Advantages: Technically, reclamation is of interest because many
foundries report that better castings can be made at lower costs, from reclaimed sand.
doc_682970187.docx