MetalTek offers more metal casting process diversity. Your ability to source centrifugal, sand, investment, HPLT, or continuous cast products from a single company is not available anywhere else in the world. Not sure which precision casting process is right for your components or application? Read the below article on the basics of casting and feel free to contact us if you have questions. We would love to become your metals partner Because You Demand More Than Metal.
Today, metal casting is a complex and intricate process which requires exact chemistry and flawless execution. While current methods may be relatively new when compared to the history of human civilization, the first casting of metals can actually be traced all the way back to around 4000 BC. In those times, gold was the first metal to be cast because of its malleability, and back then, metal from tools and decoration was reused because of the complications of obtaining pure ore. However, a copper frog is the oldest existing casting currently known; it is estimated that it was made in 3200 BC in Mesopotamia (present-day Iraq). Bronze then became the metal of choice to cast with because its rigidity compared to gold, and it was melted and cast into various tools and weapons by way of permanent stone molds. The process of casting made its way to Egypt by 2800 BC, and effectively performing this process was tremendously influential on their gain of power during the Bronze Age. Around 1300 BC, the Shang Dynasty in China were the first to utilize sand casting when melting metals. Then around 500 BC, the Zhou Dynasty introduced cast iron to the world, but it was used mostly for farmers. Cast iron did not become a military tool or decoration until the Qin Dynasty almost 300 years later.
Fast forward almost 1000 years, religion played a major role in advancing and innovating foundry technology during that time. Extraordinary evolution came from the construction of cathedrals and churches, melting and mold-making processes advanced rapidly to keep up with the demand of the dominant Catholic church. This also marked the boundary of the period between casting for the purpose of art and viewing casting as a technology with unknown potential. It was not too long after the advancements of bell casting that, ironically, a monk in Ghent (present-day Belgium) was the first to cast a cannon in 1313 with the same technology. Over 150 years after the first cast cannon, Vannoccio Biringuccio, also known as the father of the foundry industry, recorded the first written account of casting and foundry practices. His work, De Le Pirotechnia, was separated into 10 sections that covered many subjects including minerals, assaying, smelting, alloys, casting, as well as alchemy; it is one of the oldest technical documents still around from the Renaissance era.
There are many benefits of using the sand casting process versus traditional manufacturing processes. If you asked multiple metal casting suppliers the main benefit, many would say the cost effectiveness when internal passageways are required. So how does a metal casting supplier produce a finished component with these passageways? The answer is simple - by using cores. While the answer is simple, the process can be highly technical to insure a quality product. Let’s take a look at the art and science of core making.
A core is an object, typically made from sand or ceramic, that is in the shape of the passageway or void required for the finished component. In a conventional sand casting process, the two mold halves (cope and drag) are matched together, and the resulting cavity creates the exterior geometry and features of the casting. By placing a core inside the cavity, the flow and solidification of metal is redirected around the core, and the internal features and geometry of the casting can be created.
There are often alternative ways to manufacture any given component. Sometimes the first way chosen to manufacture a component is not the best way. There may be a number of reasons for that. Perhaps one has an expertise or bias for machining, or welding, or forging, or casting, or assembly. Components may end up being produced in a way that is familiar and functionally adequate, but less than optimal in terms of performance, cost, or quality.
There may come a time in any product’s life when it makes sense to investigate alternative methods of manufacture. Such evaluation would be to convert a hog-out, forging, or multi-piece weldment to a single piece casting.
What makes a good conversion?
Among the factors to consider when deciding if a design is a candidate for a conversion to a casting are cost, quality, and performance.
Some metals found early popularity primarily because of their appearance. Silver is one such metal. Relatively scarce – but not too scarce – so that it was considered valuable, silver has been an important form of currency, jewelry, and decorative pieces for thousands of years. Only as industry has understood the other interesting and powerful qualities of silver in the last couple of hundred years has the metal grown beyond the beautiful.
The first confirmed formal mining of silver can be traced back to Turkey around 3000 BC. More extensive mining through the Mediterranean areas to Spain and then other regions of what is modern Europe expanded its use as a trading commodity. Larger deposits of silver were developed once the Americas were “discovered”. Central and South America became major sources of silver through the 1600’s and 1700’s. Even today, five of the ten largest silver mines in the world are in Mexico, Bolivia, and Peru. China, Russia, and Australia are now significant producers of silver; only about 7% of the world’s silver is produced in the US and Canada.
Much of the accessible high grade ore was found and recovered by the end of the 1800’s. Some areas, often those around hydrothermal activity, still support direct mining, but today most of the silver is recovered as a (more valuable) bi-product of mining for other minerals. When mining for copper or lead, for example, the minor silver content can have more value within the ore than the primary metal. Silver is selling for more than $16 per ounce today, while lead or copper are at a dollar or two per pound, so silver is greater than 100x more valuable.