2008 Twentieth Anniversary Year

                         WELCOME              TO                                                                                                                               

2008 Wynndanzur.com

THE  CASTING  PROCESSES

_________________________________   by Wynn Danzur Marketing

Due to the Website's large size, and your equipment, this Section may take a few minutes to fully unload. 

This Section is very large and designed as Educational Tool. 

Not every Casting Process is listed, only the most commonly used. 

If there is a topic of Interested NOT presented in the entire Website, please e-mail through the webmaster,  what it is you are looking for. The best efforts will be given to accommodate requests for "Additional Sources," by return e-mail. 

The Casting Processes that are explained, are done so in a format that only Introduces the reader to that Casting Topic. It is the reader's responsibility to go beyond what this Website has initiated.

If a reader requires further in depth information on a Casting Process, or topic, this information can be obtained from the local Library, the Internet, AFS, and the Organizations supporting that particular Casting Process.

 the origin of Metal Castings  ___________________  

According to biblical records, Casting technology reaches back almost 5,500 years BC. 

Gold, pure in nature, most likely caught Prehistoric man’s fancy…as he probably hammered gold ornaments out of the gold nuggets he found. 

Silver would have been treated similarly. 

Mankind next found copper, because it appeared in the ash of his camp fires from copper-bearing ore that he lined his fire pits with. 

Man soon found that copper was harder than gold or silver. 

Copper did not bend up when used. 

So copper, found a ‘nitch’ in man’s early tools, and then marched it’s way into Weaponry. 

But, long, long before all this…man found clay. 

He used clay and made pottery, now he had something to eat from. ( Kitchen-aide and the Dishwasher, would not come around for many more years.)

Time passed ...

Then Man thought, "now…what else can I do with this clay mud stuff …" . 

Early man thought about it, "I’ll use this pottery stuff, ( the first patterns ), to shape my metal into bowls ".  

Man had discovered the Casting Industry.

Castings

A casting, is the essential foundation of civilization. With it, man unlocked his future, placing him on the path toward conquering his environment. 

History tells us this happened in Mesopotamia, today's modern Iraq. The oldest casting in existence today is believed to be a frog, cast in copper. 

The frog’s complexity indicates that it was preceded by other simpler casting efforts. Things went slow back then. 

Tin, came around in the 16^th Century, but man used earth's ores for 4500 years prior. The Chinese get the nod for iron castings around 1000 BC. India made steel about 500 BC. Civilization in general, was casting brass by then, ( brass = copper / plus zinc ) , which was many centuries before the Christian era. 

All along this path all the techniques for …" CASTING AND MOLDING PROCESSES " … were being discovered, and recorded into history. 

All of these processes would be pictured forever in time through the labors of early man.

Broken down further:

    Click on the Process Group that interests you, and that will take you to the Location.  

• Styro-foam molding
• Special V-Process Casting
• Centrifugal Castings
• Continuous Casting
• Slush Casting
• NO-Bake Casting
• Squeeze Process

  Click on the Process Group that interests you, and that will take you to the Location.  

             ***********************

           Metal Casting Process 

              Application Chart  

        " What Casting Process do I need for my Casting Project ?"

Below is a simple Application Chart  that lists the basic Casting Processes and then the type of  Normal Casting Application work that best suits that  Process. 

You can use this chart and compare the project you have in mind to determine a possible Casting Process. 

Many Processes, can be used for the same project, the quantities needed, cost per unit, tooling costs, are all factors in determining which process, is right one for your project.

                        The Application Chart

                                                [Casting Process = the normal application expected ] 

Sand Castings: everyday mechanical components, currently made as fabrications, weld-a-ments, or off the shelf assembled parts.

Green Sand Castings: same as sand castings.

Permanent Molding: depending on the situations permanent molding can be looked at as an alternate process for almost all sand casting ( green sand ), and flask-less molding processes.

Investment Casting: dental appliances, jewelry, firearms, weapon systems, engine parts, aircraft parts, anything that requires high definition, high details and easily duplicated.

Powdered Metal Casting: motor hubs, gears, spacers, magnets, slides, blanks, automotive, lawn and garden, hardware, air-movement, recreation, agriculture, elevators, escalators

The V-Process: medical equipment, machine tools, testing stands and equipment, specialty equipment, audio drivers, (speakers housings), aircraft, automotive, agriculture

Die Casting: power tool bodies, handles, parts, triggers, housings, bases, plumbing, hardware, agriculture, aircraft, rails, gates, caps, covers, tops, bottoms

Grey Iron Casting: pump housings, impellers, covers, caps, tops, bases, plumbing, agriculture, hardware, sewer covers, gears, blanks, hubs, flywheels, casings, housings

Flask-less Molding: this casting and molding process can replace sand, green sand, and used with gray iron, whenever high volume, high out put, economical, exact duplications are required

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                                        Casting Processes

                The Three Casting Process Groups 

I. CONVENTIONAL - CASTING  PROCESSES

II. PRECISION - CASTING PROCESSES

III. SPECIALIZED  - CASTING PROCESSES

I. The CONVENTIONAL CASTING PROCESSES:

1A.) SAND CASTING ( also called, GREEN- SAND MOLDING ) – is the most commonly used casting platform throughout the entire Casting Industry, World Wide. Simply put, there is a top, a bottom, and a middle to a mold. The pattern, or impression device, sits in the middle of the mold, and later is surrounded with sand . These are the basic, universal casting components, which can be applied to all casting processes.

The top and the bottom of the pieces of the mold form the flask. The flask assembly, the top and bottom, "holds the whole thing together". The upper or topmost section of the flask of the mold (flask) is called the cope, while the bottom of the mold (flask) is called the drag. The impression device, in the middle, is called the pattern. The sand around the pattern is called the, holding medium. The mold maker uses the pattern to make the impression in the sand. He then sets the pattern aside. At that point, the molder closes the cope and drag, forming the mold. What the mold maker wants is the void left from the impression of the pattern, in middle of the sand, inside the mold. So, he fills that void with a molten material.

Basic casting like this, is also called, "Green Sand Molding, or Green Sand Casting". These are the most basic molding methods, currently used in today’s casting practices, regardless of the metal alloy, or any molten - liquid material being poured. Like was said in the Preface, Man has been casting things since before Biblical times, using these very concepts.

All casting techniques employed in the rest of the Casting and Molding Processes are in many ways, just like sand casting, or green sand molding. With some thought and imagination, you can always see the cope and drag principle of casting we already discussed. The different techniques or casting and molding processes are used to achieve a desired end product, which has a special need in the market place. This special need prompted man to develop special processes.

Examples of usage would be: Air movement components ( fan blades), hubs, shafts, tubes, rectangles, squares, holes, no holes, the list is endless.

 1B.) GREY IRON CASTINGS – This process is very much like sand casting and green sand casting processes. It can be done as flask-less molding. The difference being that the molten material is gray iron.

6.) DRY OR BAKED "SAND CORE" MOLDING – very intricate automotive and agricultural castings are formed with this process. Accuracy, is the key word here along with close tolerances. A binder is mixed with un-bonded sand, it is then formed to the mold or pattern and baked. This is an expensive process, that achieves high level accuracy, in all dimensions..) DRY OR BAKED "SAND CORE" MOLDING – very intricate automotive and agricultural castings are formed with this process. Accuracy, is the key word here along with close tolerances. A binder is mixed with un-bonded sand, it is then formed to the mold or pattern and baked. This is an expensive process, that achieves high level accuracy, in all dimensions..) DRY OR BAKED "SAND CORE" MOLDING – very intricate automotive and agricultural castings are formed with this process. Accuracy, is the key word here along with close tolerances. A binder is mixed with un-bonded sand, it is then formed to the mold or pattern and baked. This is an expensive process, that achieves high level accuracy, in all dimensions..) DRY OR BAKED "SAND CORE" MOLDING – very intricate automotive and agricultural castings are formed with this process. Accuracy, is the key word here along with close tolerances. A binder is mixed with un-bonded sand, it is then formed to the mold or pattern and baked. This is an expensive process, that achieves high level accuracy, in all dimensions.  

7.) SHELL CORE MOLDS - are the earliest, most automated, and most rapid of mold, and core making processes. This technique is also called the " C " Process or, Croning. Found in Germany after WW II, from a patent issued to Johannes C. A. Croning. The " C "Process uses a fluidized, harden-able sand – synthetic resin mixture to do shell molding and shell core making. Some big advantages are closer tolerances, increased productivity, excellent casting surface finishing, almost "as cast quality ". Wynn Danzur, can work with you to determine how best this process may fit your operation. the earliest, most automated, and most rapid of mold, and core making processes. 

8.) OTHER CONVENTIONAL PROCESSES -  Loam Molds, Chamotte Molds, Compo Molds, Cement-Bonded Molds, Floor and Pit Molds, Sweep Molds( like loam molds), Open Sand Molds, Waterless Bonded Sand Molds, are some of the lesser used, but also very important processes. 

8.1) Oil Based Sand Casting - is very similar to regular sand casting and green sand casting, but a oil based mixture of sand is employed, instead of earth and sands and clays. This concept, provides Die Cast like finish, at a fraction of the cost, because no expensive die casting tools are required. When long life span, and high out put required for the application, a Die Casting is best option.

Make sure to visit Investment Casting in the Exploded Drawings, Exploded Drawings .

Some examples of usage would be: dental appliances, jewelry, components for the automotive industry, military weaponry, jet engines, aircraft structural parts, machinery components, and many others.

Investment castings works this way:

A injection molded wax pattern is used for each part produced which is then encased in multiple layers of ceramic material. The wax pattern is then removed from the ceramic shell mold. The mold is fired in an oven and then molten metal is poured into the cavities left by the evacuated wax pattern. Upon cooling, the resulting precision castings are cleaned and subjected to further processing such as heat treatment. At this point, many parts are in their final form and are ready for use while others may require a small amount of further processing such as machining before reaching their final form.

When properly applied, the advanced technology can offer complex near net-shapes that reduce overall manufacturing costs by minimizing material and labor inputs. Parts designs can be lighter in weight, more complex and are available in a wider range of alloys than those offered by other processes. Stronger materials, better surface finishes, thinner walls, difficult internal configurations and closer tolerances than those available through alternate processing techniques are some of the other advantages of the investment casting process.

The word investment, in INVESTMENT CASTING, denotes the mechanical manner of making a mold rather than the material used. This process employs a three-dimensional pattern – using all three dimensions – to produce a one time destructible mold into which molten metal will be poured. A very simple example would be to pour wax into and egg shell, let it cool, then crack away the shell. People, not especially versed in casting terms, on occasion associate this process with financial matters.

A.1) Lost Foam Process - This Process is similar to "Lost Wax", better known as Investment Casting, in that both the casting mediums are expended, either melted or evaporated away, leaving the cast part.

Make sure to visit "Lost Foam" Casting Process in the Exploded Drawings,  or Views Sections.

A.2)Ceramic Mold Casting - 

Also known as `cope and drag investment  casting'. 

The basic process is:

1.  A wood or metal pattern is placed in a flask and coated with a slurry of zircon and fused silica combined with bonding agents.
2. The mold is removed, cleaned and baked. The shells may be used as given, or they may have other materials, such as clay put on as backing materials.
3.  The molds are then used as normal.

 This can make high temperature material parts.

 B.) THE SHAW PROCESS – this is one of the best known of the INVESTMENT CASTING variations. The chief difference is that a jelling agent is added to the inside of the destructible mold …instead of cracking away the mold, it is stripped away.

C.) REPLICA CASTING – can be made from any material that can be burned away, burnt out, or incinerated …leaving a pattern chamber free of ash and residue. Examples would be…plants, seedpods, insects, etc. This method is for very intricate designs, costume jewelry, precious metal replica.

D.) RUBBER MOLDS – is made of silicone or vulcanized rubber. It is a form containing the impression of an original mold. It is then filled with wax to duplicate identical molds of the original. A slurry is dipped around the wax, the wax burnt out and the molten metal poured into the void left by the burnt away wax. A simple example would be a mouth piece for dental work.

E.) SPIN CASTING – this bridges the gap between die casting and sand casting by incorporating the some of the important advantages of both of those processes. 

E.1) Centrifugal Casting - is another name for this same Process.

Production of prototype castings, in high or low volumes, with low tooling costs and short lead times, yielding die cast quality parts known for the close tolerances.

How it all works:  

" ...Imagine a star inside a circle both made of rubber. At the ends of the points of the star are the patterns…the arms of the star are the sprues for the molten material to flow out to the patterns. The circle is spun and the molten material is poured into the center of the star… the spinning motion casts the part.

F.) PERMANENT MOLDING – is very much like sand casting, but no sand is used, and there is no real impression device…just a metal vessel shaped to the configuration of the part wanted, this is the impression device. 

The vessel is closed, an molten metal is poured inside, there it is allowed to cool and set up. Then the "cope and drag " are opened up and there is the cast part. 

In Permanent molding, just as the names states, the mold is permanent, in that it is used over and over again, unlike a sand mold, that is re-made, after each sand cast part, is produced. 

Alloys suited for Permanent Molding both ferrous, and nonferrous. – is very much like sand casting –but – no sand is used, and there is no real impression device…just a metal vessel shaped to the configuration of the part wanted, this is the impression device. 

The vessel is closed, an molten metal is poured inside, there it is allowed to cool and set up. 

Then the "cope and drag " are opened up and there is the cast part. In Permanent molding, just as the names states, the mold is permanent, in that it is used over and over again, unlike a sand mold, that is re-made, after each sand cast part, is produced. 

Alloys suited for Permanent Molding both ferrous, and nonferrous.

Permanent Molding is also referred to as Gravity Die Casting. 

Advantages of Permanent molding over other processes are; 

the molten metals cool more rapidly than sand, producing a sound dense casting with superior mechanical properties, high degree of uniformity, high degree of dimensional accuracy, less scrap castings, more machining secondary operations can be " cast-out " of project – reducing overall costs, a consistent quality finish. 

All casting techniques employed in the rest of the Casting and Molding Processes are in many ways, just like sand casting, or green sand molding. 

With some thought and imagination, you can always see the cope and drag principle of casting we already discussed. 

The different techniques or casting and molding processes are used to achieve a desired end product, which has a special need in the market place. This special need prompted man to develop special processes.

Examples of usage would be: Permanent molding can replace just about all sand casting applications, where the benefits listed above are desired.

G.) DIE CASTING – this process is for high volume, high detail, value added, economy priced,  cast parts.

A metal tool is built, and it is attached to a furnace of molten metal, this molten metal is mechanically poured…injected into the metal mold, the mold cools for a brief time, it opens the parts come out… the process repeats, over and over and over. Advantage is very high production with great duplication, with great tolerances.

An Aluminum Die Casting - is a process where molten aluminum alloy is injected into a closed vessel called a casting die or mold, under high pressure and at a controlled temperature. 

The mold has sections which include the "cover" or hot side and the "moveable" or the ejector side. 

The die may also have additional moveable segments called slides or pulls which are used to create features such as undercuts or holes which are parallel to the parting line. 

Aluminum die casting molds operate in cold chamber die casting machines. 

These machines run at the required temperatures and pressures to produce a quality part to net-shape or near net-shape specifications. 

Aluminum die castings can be readily machined, anodized, painted or powder coated.

Examples of usage would be: cabinets for the electronics industry, hand and power tools for industrial and home use, general hardware appliances, pump parts, plumbing parts, parts for the automotive industry, sports and leisure, home appliances, a lot of communications equipment, the list is endless.

Zinc die castings - poured from Zamak #3,#5 or #7 or a zinc-aluminum alloy casting made from ZA-8, are made very similar to aluminum die casting.

The molten metal is injected into a closed vessel called a casting die or mold under high pressure and at a controlled temperature. 

The metal is cooled rapidly until the solidified part is sufficiently solid enough, to permit it to be ejected from the mold. 

The mold has sections which include the "cover" or hot side and the "moveable" or ejector side. The die may also have additional moveable segments called slides, or pulls which are use to create features such as undercuts or holes which are parallel to the parting line.

Zinc die casting dies or molds operate in hot chamber die casting machines. These machines run at the required temperatures and pressures to produce a quality part, to net-shape or near net-shape specifications. Zinc die castings, can be readily machined, plated, painted or powder coated.

Examples of usage would be: all general hardware type parts, hardware for doors, drawers, and furniture, plumbing fixtures, automotive products, parts for the lighting industry, all hand tools, power tools, sporting goods – list is endless.: all general hardware type parts, hardware for doors, drawers, and furniture, plumbing fixtures, automotive products, parts for the lighting industry, all hand tools, power tools, sporting goods – list is endless.

 H.) POWDERED METAL CASTING – this process is also sometimes referred to as the sintered metal process, we will always refer to this as Powdered Metal Casting.

 Casting Industry professionals across industry depend on Powdered Metal, for cost effective production of parts.

The Powdered Metal Casting Process is the absolute choice for parts that require high mechanical properties with repeatable close tolerances. That's why this modern technology is so popular today.

The advantages of Powdered Metal Casting process are:

1. Unlimited choices of alloys and associated properties

2. The metal properties can be specialized for most any application

3. The process is suited well for moderate to high production quantities

4. Powdered metal process offers long term reliability, too. Close control of dimensions and physical properties are an inherent part of the process. In addition, powdered metal parts are produced with net shape, requiring little secondary operations like machining.

 The Powdered Metal Casting Flow Process Description:

1. 1. dispense measured quantity of powder metal into mold
2. 2. compact powder with high pressure machine tool
3. 3. extract compacted part
4. 4. sinter part in an inert atmosphere at controlled temperature and time

Examples of usage would be:  fan hubs, motor hubs, magnets, automotive, farm, aircraft service equipment, power tools, machine tools, etc.

I.) OTHER PRECISION MOLDING AND CASTING PROCESSES 

Acurrad Process

Plaster Molding 

Antioch Process 

Graphite Molding

 Are some of the other processes

III. Special Casting Processes

A.) THE "V PROCESS "  - permits molds to be made for the first time, out of free-flowing, dry, un-bonded sand without using high pressure squeezing, jolting, slinging, or blowing as a means of compaction of the sand used in conventional casting. 

This process is dimensionally consistent, economical, environmentally and ecologically acceptable, energy thrifty, versatile and clean.

How it all works:

A thin plastic film is heated and place it over a pattern. A vacuum tightly draws the film around the pattern which is then surrounded by a flask. Next, the flask is filled with dry, un-bonded, extremely fine sand and vibrated, so that the sand tightly packs the pattern. A second sheet of film is placed on the flask, a vacuum draws out the remaining air, and the completed mold is then stripped from the pattern.

Each half of the mold is made in a like fashion. Aluminum or the Alloy of choice, is poured to form the casting.

Examples of usage would be: the medical equipment, instrumentation, electronics, machine tool , aircraft machine tools, musical drivers ( speakers ), church bells, automotive testing and repair equipment, to mention just a very few applications.

Use the Table of Contents, to visit the Exploded Drawing Section and see a colored drawing on the V-Process.

Follow the numbered steps listed below to get a better understanding of this V-Process. 

1. set a pattern on a hollow carrier plate.
2. a heater softens up a thin sheet of plastic film.
3. film is draped over the pattern, and a vacuum sucks the film down over the pattern.
4. flask is set on the film coated pattern.
5. flask is filled with dry sand, it is vibrated slightly to settle the sand.
6. the sprue-cup is formed, the mold is leveled…the sprue-cup and flask are covered with plastic film.
7. vacuum is applied to flask, and hardens the sand, containing the pattern.
8. cope and drag are both formed in this manner and assembled.
9. plastic lined cavity is under vacuum.
10. molten metal is poured in, left to cool, part is done, plastic melts evaporates away into sand.

B.) STYRA FOAM MOLDING – think of permanent molding, or sand casting, green sand molding.  But, instead of sand, a permanent molding tool, STYRO-FOAM is used as the pattern material. Most times the styro-foam pattern is laid out by a computer, then air cut to the shapes needed, or many shapes fastened together to form pattern.

During the casting process, which would be just like sand casting, with the pouring of molten metal into pattern cavity, which in this process is styro-foam, sometimes the styro-foam is burned away, and sometimes it is not. This depends on the application of the actual component being cast. 

See Lost Foam Casting above, and visit the exploded drawings or views Sections.

Examples of usage would be: large tooling for aircraft, bridge decking, highway barrier components, elevator components, to mention a few applications.

C. OTHER SPECIAL MOLDING AND CASTING PROCESSES –

Continuous Castings  

Slush Castings 

 " No-Bake" Casting Process 

 Squeeze Casting

There are many more Casting Processes, and variations, all of which have their  purpose in the casting of parts. 

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                                                      Thanks for visiting us, please come back soon.   

                                                          Wynn Danzur Marketing

                                                                                     PO Box 662

                                                                        Versailles, Indiana 47042

                                                                               Ph: 812-689-0793

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