Metal Die Casting and Metal Foundries
Is Metal Casting the “Most Fundamental” Industry?
On the North American Die Casting Association’s website, the association says that metal die casting is America’s most fundamental industry. Is this true? Should you take a metalworking association’s word for that kind of statement? I think it’s impossible to evaluate one sector of the economy as “most fundamental,” but they’re certainly right that metal casting is an extremely important industry.
What I’ve found in the time that I’ve been writing about industry is that different disciplines and industrial sectors are inseparable from one another. The computer industry and the casting industry, for example, are codependent. The computer industry needs casting companies to make heat sinks and other vital computer components, and the casting industry needs the computer industry to manufacture hardware that can manage its CNC manufacturing processes. Think of any example of a sector in industry and I guarantee that you’ll find at least one other sector that it is codependent with.
Die casting companies are no exception to this rule. The low hanging example fruit, when it comes to die casting, is, again, the computer industry. Many computers involve at least one die cast part, and die casting operations are often managed by CNC hardware and software, which the computer industry produces. But there are many other examples as well. Die cast parts are involved in the equipment that is used to extract raw metal, and that raw metal can then be used to make more die castings. There are many other examples.
Die casting is an excellent example of the codependence and interdependence of industrial sectors. Even though the NADCA insists that metal casting is the most fundamental industry, bear in mind that no industrial sector could exist without depending on other sectors. This is the reality of a developed, industrial economy.
Metal Foundries: A Look Inside
A metal foundry is a place where metal is transformed from its base material into useable ingots that can be transformed into usable metal pieces. Some foundries shape their own metal pieces, while others ship the finished metal off to other factories for further processing.
There are a variety of different metals that can be used to create metal casting and shapes. Usually, aluminum and iron are used, but other metals, like bronze, steel, copper, tin, magnesium, and zinc are also processed in a factory and shaped into parts using metal casting. Most metal foundries use a special kind of metal casting to create ingots or other metal shapes for further processing. A metal foundry typically uses a multi-step process to finish the metal pieces.
First the metal is melted in a large container and any impurities are removed. If the metal will be a combination of metals, they are added at this point and mixed together. Most foundries use a furnace to melt the metal. After melting, some metals require degassing. Degassing is the process of removing hydrogen in the metal. Too much hydrogen produces a porous metal that has little use. Degassing is done by bubbling nitrogen or argon into the metal while it is still in liquid form.
After melting and degassing, the metal is poured into a mold. Different foundries will have different molds available, such as ceramic molds, sand molds, investment casting, die casting, billet casting, or lost-foam casting. Usually the metal is poured into the molds using robotic pouring systems.
The metal is allowed to cool, then removed from the mold. The metal piece then goes through a degating or deburring process, which removes unwanted pieces from the mold. The metal piece then may be heat treated to give it extra strength, or simply cleaned and polished for final use.