History of Metal Fabrication
Metal fabrication has a history that goes back centuries. Historians agree that humans started working with metals almost 9,000 years ago.
The Bronze Age started around 3300 BC and was a turning point in history. The ability to mix metals, melt them into alloys and form them into objects led to the rise of civilizations based on advanced weapons of war. Middle ages people have seen metalworking as a skill given by gods and correlated with the planets. There were seven metals: Mercury, Gold, Silver, Copper, Tin, Lead, and Iron. They were related to the Sun, Moon, Mercury (obviously), Venus-Mars, Jupiter, and Saturn.
A rolling press was invented by Leonardo da Vinci almost 100 years ago. His 1495 patent-worthy press idea was conceived in 1590. It was only in the 1700s that the Industrial Revolution began, and the plants creating nickel and lead plates made metalworking possible in a new dimension.
In addition, a few years later, the nibbling machine was created that allows sheet metal to be cut through exact holes. For cutting large-thickness sheet metal at the end 19th century, the oxyhydrogen torch was invented. This torch used oxygen, light gas, and hydrogen. Historians claim it was used for the first time to burgle an unsafe! Over the years, many other cutting techniques have been created, such as waterjets, laser, plasma cuts, and so on. Their history is still to be told.
The invention of Plasma Cutting
On September 10, 1957, Dr. Robert Gage at Union Carbide’s Linde Division was the first to approve a plasma cutting patent in the US. Plasma cutting was born out of plasma welding during the 1960s and then emerged as a highly efficient method to cut sheet metal and plates during the 80s. It was superior to the traditional “metal against metal” cutting in such a way that metal chips were not produced, resulting in precise cuts and providing an edge cleaner than oxy-fuel cutting.
Engineers worked hard to improve the quality and safety of torch cuts throughout the 1960s. Fabricators discovered that plasma metal cutting could be used for non-ferrous materials to create complex shapes at very high speeds. Plasma uses heated compressed gases like hydrogen and nitrogen, which are emitted from the nozzle with such high velocity that they become charged/ionized and conduct electricity.
Water-Jet Cutter Invention
The initial usage of water jets goes back to the Roman Empire, Romans used it to clean the land from the unneeded ground and for other development purposes. In recent history, waterjet cutting first came into use in the 1850s for excavating materials from coal mines in New Zealand and Russia. The hydraulic mining method was then adapted to coal mining by miners from California and was used to search for gold hidden beneath the rock. In the early days, steam power enabled the water to attain a pressure of 800 PSI.
In the early 20th century, Elmo Smith thought of an idea to make the water stream be able to cut through hard substances. In 1935, Smith devised the idea of adding abrasive particles into the flow of water to use the purpose of liquid abrasive blasting. Smith’s idea was additionally elevated and completed by Leslie Tirrell 1937, who worked for the Hydroblast Corporation.
Waterjet Cutting Shoots concentrated streams of water at high speeds that contain abrasives, such as garnets or aluminum oxide, to erode the cut through the material. Water jet cutting requires high power, up to 60,000 psi. Therefore, it is used in thicker materials where a traditional laser is not feasible or results in poor cutting. Water jet cutting can cut sheet metal and steel, ceramic, and stones.
Oxy-fuel Cutting or Flame Torch Cutting Method
The process is often referred to as Flame Cutting. It is known by numerous other names, like Oxy-Fuel Gas Cutting, Oxy-Acetylene Cutting, Oxygen Burning, Steel Burning, and other numerous names too to add-in list. First, it was used for commercial purposes, and the British called it “an unauthorized bank entry” or “safe cracking”.
The cutting process using oxygen fuel has been mostly the same since its beginning. But, even after over 100 years of use, it’s essential to cut through thick steel. The only cutting technique that can cut steel is 30” in thickness or more.
Walter Roberts was among the individuals in charge of the creation of the oxygen-acetylene procedure. He came from England to participate in a research project to produce oxygen. One of the first tasks was to clean up the Quebec Bridge, which had fallen into the St. Lawrence River in the early part of 1908. A couple of attempts to demolish the bridge to remove it was unsuccessful. Roberts persuaded the authorities to let him try using an oxygen torch and succeeded.
A more convincing example of the power of cutting the oxy-acetylene was dismantling boilers on the Kentucky Battleship. The 1910 vessel was located in Norfolk to prepare for an overhaul. Workers equipped with cold chisels and hacksaws started cutting the 1-1/8-inch boiler plate in order to remove the boilers. After three months, they had completed about a quarter of the task. Roberts offered the Navy to complete the task, but they were doubtful, and only decided to try after Robert claimed he can do the job in just 10 days. They took the boiler down within under 10 days.
The mixture of oxygen with the fuel gas is used in order to heat the metal to the “ignition temperature”. This is, for steel, 700°C to 900°C (bright red hot), but below its melting point. The oxygen is directed through the jet into the heated area to cause an exothermic chemical reaction between the oxygen and the iron to create iron oxide. The oxygen jet blows out the slag, allowing it to penetrate through the material and continue cutting through it.
Today’s Precision Metal Cutting – Laser Cutting
It was in 1965 that the first commercial laser cutting device was introduced to create holes into diamond dies. This machine was manufactured in the Western Electric Engineering Research Center. In early 1967, the British pioneered laser-support oxygen-jet cutting to cut metals. In the 1970s, this technique was developed to cut titanium, allowing them to make it suitable for aerospace. CO2 lasers were modified to cut non-metals like textiles since, at the time CO2 lasers weren’t powerful enough to combat the conductivity of heat in metals.
Fiber is the latest accessible form of laser cutting. Commercial laser machines were introduced in 2009. In 2007, Salvagnini, an Italian technology firm, started looking into the possibilities of using fiber laser technology to cut sheet metal. They had invested heavily in developing CO2 laser-cutting equipment but discovered that they could only achieve modest performance improvements. The L1Xe fiber laser, capable of cutting 18mm of steel, was first introduced worldwide at the EuroBlech show in 2008.
Since laser cutting has a short history, massive advancements have been made, and the technology continues to fast develop, including the latest fiber lasers able to cut with up to 100mm of stainless steel.
Laser cutting is a safe, efficient, and accurate method to cut sheet metal. A laser cutter is programmed that precisely cuts material within a defined cutting tolerance. This tolerance is also known as an acceptable precision range. Laser cutters often integrate with CAD software, which commands the laser how and what to cut. CNC laser cutting is easier than traditional methods and safer because it’s computer-guided.
This article is brought to you by Metaline, an Ontario-based metal manufacturing factory. In 2021 Metaline company was proud to operate the most advanced laser cutting machinery in Canada.
