The Beginning

Metal has shaped the history of the world from the copper frog of Mesopotamia to the skyscrapers in modern day New York City. It shapes landscapes, connects people, and makes modern technological marvels possible. Metal Casting is arguably the oldest known Industrial process. In fact, it has made such an impression on the history of civilization that we recollect the ages based on the metals that were predominantly used during said time periods.

History of Metal Casting

The Copper Age

At the beginning of man’s journey to modern day. The initial casting process was conducted using copper which would have been poured into clay and beeswax to make household tools, jewelry, and weapons. Copper was the metal of choice due to its easy workability.

 

The Bronze Age

After the discovering the benefits in durability that mixing metals presented, The Bronze Age began. Tin and copper would be mixed in a more complex casting process.

 

The Iron Age

In this age, by no surprise, iron was utilized. This was also the point in time when mass production started to become common for farm equipment and later on more technologically advanced weapons and more. Following this age would be none other than the industrial age in which casting would become even more widespread. Innovations in travel and everyday utensils would call for an even greater production of metal castings.

 

Metal Casting Technology

Cupola Furnace

This once industry giant was invented in 1720 to melt cast iron and some bronzes for casting. The Cupola furnace takes the shape of a silo using coke to heat the metal as it drips down to the bottom of the cupola and is retrieved through the bottom door. Though the most popular choice of its time, the Cupola Furnace has since been vastly replaced by more modern methods.    

Crucible

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The word Crucible may bring you back to your high school classroom if you grew up in America. It is essentially a pot in which you can melt material at a high enough temperature without melting the tool itself. In the 18th century, it was a tool in which to melt steel, in fact, the very first actually to do it well.

Electric Arc Furnace

Most commonly used today, this furnace heats metals by way of direct exposure to the electric arc. This type of furnace can be enormous in size and heat up to 5,432 degrees Fahrenheit. Arc furnaces are generally used for industrial melting of cast iron for the purposes of steel casting, however, they can also be used for dentistry and research on a smaller scale.  

Induction Furnace

The Induction Furnace as you may have guessed heats metals by way of induction. Heat is transferred from the metal walls to the metal that is being melted. This type of furnace is more often chosen for its stability and even temperatures. Most commonly used to melt steel, precious metals, copper, aluminum, and iron.

Processing Equipment

Processing equipment such as General Kinematics offers, provides a way to move castings through your process and clean, reclaim, and cool your castings. GK equipment for metal casting handles the extreme heat of a newly finished casting and speeds up your process to yield a higher quality product.

 

Methods of Metal Casting

Investment Casting

Investment Casting, a term referring to the pattern being filled with metal or invested in. This method uses wax coated in ceramic and backed by sand is less commonly used due to the inability to reclaim the ceramic.

 

Lost-Wax Casting

One of the oldest methods of casting, as mentioned in “The Copper Age”, lost-wax casting was originally performed using beeswax and clay. The method used today may still involve wax and clay but many additives of the modern era have improved the dependability of the wax. This process is preferable due to its repeatability. Another similar method of casting is lost-foam casting, similar to traditional lost-wax but with fewer steps and using styrofoam instead of wax.

Sand Casting

Sand casting refers to a process in which sand is mixed with a binding agent to make a mold. The sand is contained in a box called a flask into which the molten metal is poured. This process is preferable due to the low cost of sand and its ability to be reclaimed. Using equipment such as the GK VIBRA-MILL™ Sand Reclaimer the sand is broken down and recycled back into the process.

Die Casting

Die Casting creates metal castings by injecting molten metal into a casting that ejects the final product once it is cool. This process is perfect for high volume production of smaller castings. Though the process of running die casting is economically steady the initial purchase of equipment is the main hurdle for this endeavor.

Continuous Casting

You may have heard this process called by another name, strand casting. Praised for saving processing time, continuous casting is performed by melting metal, allowing it to solidify in a slab, and running it through the mold while the metal is semi-soluble.  

 

Famous Castings

 

The Liberty Bell

The Liberty Bell was made in the London Borough of Tower Hamlets by a highly distinguished foundry most commonly known for making church bells appropriately named the Whitechapel Bell Foundry. The foundry itself has a resume worthy of the infamous Liberty Bell’s production. Opened in 1570 the foundry was in business for 450 years until its closure in 2017. Not only was the Whitechapel Bell Foundry responsible for the original production of the Liberty Bell, a well-known symbol of freedom in the United States, but also the bell in Big Ben, a famous London landmark. If you wish to view a remnant of this historic foundry, the final casting is on display at the Museum of London.

The Statue of William Penn

The gigantic statue that tops Philadelphia’s city hall nearly three centuries after the opening of the Whitechapel Bell Foundry, Tacony Iron and Metal Company began work on the statue that would spark legends. The massive 37-foot tall statue of William Penn (founder of Pennsylvania and city planner to Philadelphia) would be cast in sections and fitted together atop the dome of city hall. Tacony Iron and Metal Company eventually closed its doors in 1910, but its legacy lives on in the mysterious statue that “cursed” the city. The statue had been blamed for the failings of local sports teams to win championships since the construction of a building that sat taller than the statue of William Penn. The local name for this cure was “the curse of Billy Penn” which finally came to a conclusion when a small statue of William Penn was placed atop the taller building and the Phillies won the 2008 championship.

 

Casting a Legacy

 

Whether it is brake discs or the Liberty Bell, your castings are a legacy for those around you. With any luck, they won’t end up cursing an entire sporting community, but no matter the case General Kinematics has your back for any processing challenge. We are proud to have our own legacy of solutions that work to make the process easier and more efficient for any casting endeavor from 37-foot tall statues to 3-inch valve castings.

Talk to our foundry equipment experts today to learn how GK can improve your process.

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