Human beings left the Stone Age behind roughly 4,000 years ago when the Bronze Age began, although some foundries go back even further. The team at Cast Technologies takes great pride in coming from a long line of skilled craftsmen that reaches back to the ancient world. We are today using processes based on the same principles as those used by our ancient ancestors to radically change and modernize the world. While people might think of things like electricity, the printing press and computers as the building blocks of the contemporary world, the truth is our way of life rests to a very large degree on the work of foundries: Automotive, air travel and energy production are just three industries that heavily depend on cast items. You depend on multiple cast items every day of your life.

Naturally, modern foundries bear little resemblance to the primitive technologies that man invented to make weapons and tools from simple bronze alloys, but the ideas are much the same: Melt a mixture of metals together and pour the liquid into some kind of mold. Making a bronze spearhead uses much the same technology still used for making parts for a power generator.

The ancients made things like weapons and plows, allowing them to put aside their more primitive stone tools. Today, foundries make an almost infinite number of items we rely on in modern life, including car engines, pipes, chains, aircraft parts, tools and many other metal components. Of course, foundries today aren’t limited to bronze, but can cast countless metal alloys depending on the characteristics required by the finished item. 

How Has Foundry Technology Changed?

Foundries have evolved considerably, thanks to advances in technology and the science of metallurgy. Initially, charcoal fires were used to power little furnaces hot enough to melt metal, but now gas or electric heat are used to power more advanced furnaces. 

Early foundries were a dangerous work environment, but modernization and mechanization have made them much less hazardous. For example, pouring molten metals into molds via a robot or other automated equipment is much safer than pouring by hand using a ladle. 

Another change in foundries involves the methods used to placing the molten metals into molds. Traditional gravity pours are still used, but there are other methods available now, including vacuum or pressurized gas pours.

A Simple Explanation of the Foundry Process

Imagine you are living a few thousand years ago and you wanted to cast a simple item, such as a flat disk, in metal. The easiest method would be something called sand casting.

You might start by carving something called a pattern from wood. Once you had your desired shape just as you wanted it, you could sink it into a sandpit and then — very carefully! — you would remove your wooden model from the sand. Done right, this would leave a perfect impression of your wooden model in the sand. 

Next, you would prepare your metal according to the characteristics you wanted your finished item to have. Perhaps you’d follow the ancient recipe of one part tin to nine parts copper. You’d need a small furnace, a clay melting pot and of course a hot charcoal fire for melting. Yes, primitive charcoal-fired furnaces can indeed get hot enough to melt copper and tin together, although it’s much easier to achieve the necessary temperatures in a modern foundry.

Once your metals had melted together, you’d carefully pour your mixture into the sand cavity and let the metal cool. Finally, you’d remove the solidified metal disk from the sand. If all went well, you’d have a perfect metal copy of your wooden disk.

Now let’s imagine you wanted to make a more complex casting. You might want to make your item in two different sections, a top and bottom. This is called a split pattern, and the upper section is called the cope, while the bottom section is called the drag. 

Even more complex designs can be made using something called a core. The core is inserted into the mold to create a hollow area. 

Now imagine you needed your item to have a smoother finish. You could smooth it out by sanding or grinding. Today, you might sandblast the surface, sand it or machine it smooth with a grinder. This same general process is used in making everything from the simplest tiny items, such as jewelry, to the most complex and large parts weighing hundreds of pounds, such as wind turbine blades.

After the item comes out of the mold, further processes may be used if necessary. Cast Technologies has an on-site machine shop to add the finishing touches to any component.