There is not a moment of the day when massive metal fabrication projects are not underway somewhere in the world.
The modern, technological society of today requires a steady stream of manufactured metal objects, whether as parts for other objects or as finished goods like cars, trucks, railway cars, aircraft, ships, fuel tanks, medical machinery, refrigerators, stoves, tools, furnaces, and countless other items and appliances.
Nearly all of these devices include at least some welding, and the colossal numbers and high-precision assembly needed for all of them drives another need – a requirement for industrial welding machines.
Industrial welding machines are welders manufactured to be able to handle large volumes of welding in a short time – and, frequently, to provide very large, strong welds as well. A small, slow welding machine will not be sufficient on an assembly line that rolls out a thousand new cars a week.
In these cases, the welding machine must be not only quick and durable but powerful as well.
Types of Industrial welding machine
Industrial welding machines are not a single, overall type that is good for all heavy-duty work and does not vary between factories. Instead, they are probably even more diverse than the smaller-scale, portable, or workshop-based welding machines, as the tasks they face are not only more challenging but more various as well. A few of the more common types include:
Seam welding machines – seam welding machines operate on the electrical resistance welding principle.
These machines roll the edges of the two pieces of metal sheeting to be joined between two copper wheels, which are actually electrodes linked by a high-ampere electric current.
The metal resists the electricity, which converts the energy to heat, and as the metal becomes molten, the two pieces are squeezed together and combined at the weld. The electrodes roll the sheets steadily forward, quickly creating a strong, continuous welded seam.
Spot welding machines – these large-scale relatives of the portable tong spot welders that were pioneered in Wisconsin by Niels Miller also operate on the electrical resistance principle, though the electrodes do not move the workpiece.
The spot welder makes a weld at a single spot, tacking the pieces of metal together. This method is often used in automobile manufacture.
Wire mesh welding machines – ranging from fairly simple roller-and-die machines that create a square or rectangular wire grid for fencing to sophisticated computer-guided machines that feature multiple welding heads and are shuttled back and forth on servos to weld complex patterns of wires or rods to create everything from shopping cart sides to concrete reinforcement, wire mesh welding machines are purely industrial devices thanks to their large size, cost, and complicated maintenance and operation.
Plasma arc welding – plasma arc welding, or PAW, is another application of electric arc welding which places the electrode inside the welding torch.
This creates a plasma arc that is squirted out through an extremely fine nozzle made of copper, meaning that the plasma is accelerated to close to the speed of sound and can reach temperatures of around 36,000 degrees Fahrenheit, or about four times the temperature of Sol’s surface.
This welding method is an advance on MIG welding and is often used in industrial applications.
Submerged arc welding machines – another type of industrial welding machine is the submerged arc welding machine.
This is a flat-bed welder which is used only on horizontal welding because of the nature of the process.
The machine is almost always run automatically, on a pre programmed basis, thanks to the special constraints of the method.
The entire welding area is covered in a slurry of flux, which conducts the electric arc from the welding electrode to the work piece.
The weld is constantly submerged under this pool of flux, preventing spattering and oxidation without the need for shielding gas.
The welding must be carried out in the horizontal position so that the flux does not simply run off. However, the method allows welding at speeds ten times faster standard gas-shielded welding, while maintaining a very high quality of weld.
Laser Welding Machine
Most of the modern day’s welding techniques have been in existence for nearly a century now, and some of the arc welding principles were guessed at as long as two centuries ago by the Russian discoverer of the electric arc.
TIG, or tungsten inert gas, welding was developed before World War II, for example, and was expanded and refined in response to the need to manufacture many combat-ready aircraft with welds that would stand up the stress of flying in dogfights and bombing raids.
Many technical improvements have been made in these welding methods over time, but the basic principles are still recognizably those used generations ago in factories, shipyards, and workshops.
Laser welding, on the other hand, is a relative newcomer to the welding scene. Just a few decades ago, laser welding machines had just been built for the first time, and were so problem-riddled and inconvenient that they were used for a handful of highly specialized applications only.
Research and development has been brisk, however, and laser welding machines are now used in many places, from car factories to cigarette lighter manufacturers and all other types of metal fabrication operations.
These welding machines have several unique features that make their welds different from those provided by more traditional welder.
Welding with a laser welding machine
A laser welding machine makes use of a beam of extremely concentrated light, generally outside the spectrum visible to the human eye, to heat the materials that are being welded.
The beam’s light energy is converted to heat energy as it is absorbed by the metal it is focused on, and this heat, in turn, melts the metal and creates a weld.
The problem with this picture is that laser energy is light, and metal tends to be reflective, so a good portion of the laser beam reflects away rather than being absorbed, so laser welding is no more energy-efficient than other types.
It has several advantages that help to counterbalance this fact, however.
One characteristic of laser welds is that the welds are very narrow and precise.
The extreme weld narrowness possible with laser welding machines means that the technique can be used for fine work as well.
The two types of lasers that are used for welding most often are Nd:YAG and CO2 (carbon dioxide) lasers. Nd:YAG lasers have a relatively low energy output and produce a narrow, shallow weld at a high rate of speed.
Carbon dioxide laser welding machines, on the other hand, are very powerful can produce unique deep, narrow welds of very high quality, through a process known as keyholing.
Keyholing involves focusing the laser at one point on the metal until a hole is formed, which fills with vaporized metal.
This metal vapor absorbs huge amounts of energy very efficiently and transmits it as heat to the nearby metal.
The laser can then be advanced, and the heat is so intense that the metal melts deeply but narrowly, flowing in to fill the cavity behind the laser (which started with the keyhole) and forming an extremely deep, narrow, strong weld. This procedure can be used on a wide range of metals such as carbon steels, stainless steel, aluminum, and titanium.
Laser welding machines come in all sizes – from huge industrial lasers to “micro-laser” welders (generally of the Nd:YAG configuration). The laser welding machine is slow to penetrate many industries due to ‘technical inertia’ and resistance to the unfamiliar, but given its unique welding properties, laser welding will probably continue to gain ground and become more accessible.
MIG Welding Machine
Operating on a similar principle to other arc welders, such at TIG welding machines, the MIG welding machine offers considerably easier use – it can be learned quickly, unlike highly skilled TIG welding, and is straightforward enough so that it can be used in completely automatic welding processes rather than as a manual welding technique.
The familiar images of robotic welders assembling cars in Japanese factories show MIG welding machines in action. Although it is simple and cheap, MIG welding does have a downside, however – the joins are not as strong as TIG welds, and they tend to be far messier, with large amounts of slag left near the weld site. This hard residue will destroy electronics if it becomes fouled in the wiring, so MIG welds cannot be used in electronics welding as TIG welds can, or in any small application where a clean weld is essential.
MIG welding machines are arc welders that use a powerful electric current to generate heat at the welding point – heat sufficient to melt whatever metal is being used for the project.
The electrode that provides the heat is, at the same time, the filler metal that melts and bonds the two parts being joined.
The electrode is therefore consumed while welding is going on, and in place of a permanent electrode, MIG welding machines are fitted out with a long wire that feeds continuously from a large spool inside the welding machine’s body, constantly melting its own tip into the weld while being replenished from the spool.
An inert gas known as a shielding gas surrounds the welding point – this leads to the welding process’ name, since MIG stands for Metal Inert Gas.
Uses and limitations of MIG welding machines
A MIG welding machine is good for several different applications, and in all cases it is preferred over the higher-quality welds of the TIG welding machine wherever speed, low cost, and ease of use trump a very strong weld.
Car factories are frequent users of MIG welding machines because a car chassis is not subjected to extremely strong forces, so it does not need exceptional welds, because the car body material is very thin, and because the MIG welding process is simple enough so that it can be carried out by robots.
MIG welding is close to a point-and-click style of welding and can be learned within a matter of days rather than through months of training and practice.
The electric arc heats the tip of the wire until it is molten and runs onto the joint that is being welded, while rollers in the welding machine move more wire forward from the onboard spool.
The melted electrode forms the welding pool that creates the weld, and the coating on the wire forms into a small cloud of gas around the welding point, ensuring that oxygen does not reach the molten metal.
Argon is the usual “shielding gas,” since it will not burn or explode in the electric arc of the welder. It is dangerous if inhaled, however, since it can kill the brain by displacing all oxygen from it, or kill the lungs outright.
Because of the need for shielding gas, MIG welding usually cannot be employed outdoors without building a special structure around the welding site to exclude wind.
Although MIG welding machines are quick and easy to use, they do have limitations thanks to their heavy deposition of slag on the surface of the object near the weld (which must then be scraped off, if possible), and because they have low weld penetration.
MIG welding is best on thin metals, such as stainless steel, steel, and aluminum.
Thicker metals and welds that need to be exceptionally robust – such as those that will be subjected to a lot of atmospheric or water pressure, as in the case of an aircraft or boiler – need the greater penetration and stronger welds of other welding techniques. However, it is excellent for many applications where an average-strength weld is sufficient, and small, portable models are ideal for the casual home welder.
MIG Welding Machines
Developed in the grim shadow of World War II – the cataclysmic time when European civilization was savaged by the ambitions of dictators, and there was a pressing need for assembly methods that would allow the fast, strong, accurate construction of thousands of aircraft, tanks, tank destroyers, artillery pieces, and small arms – the modern arc welding machine is an effective, practical device that can handle many different jobs.
From the home workshop, carrying out repairs on pickup truck beds or creating metal garden art, to the mighty factories that churn out the endless metal goods used in the modern world, arc welding machines are present everywhere, and are likely be used for many decades to come.
Among the many types of welders that have been developed over the years, MIG welding machines are the easiest type of arc welder to use.
Someone who has never used an arc welder before can learn the MIG technique within a few days, and start to apply it to work – whether as part of a company workforce, or independently, as a freelance welder or home enthusiast.
How a MIG welding machine operates
As with all welders, the action end of the MIG welding machine is the welding gun – the device the user holds to direct the electric arc at the welding point, and which performs several other functions that are needed for the welding process to be successful.
The welding gun operates by using an electrode to pass an electric arc into the steel, aluminum, or other metal that is being welded, which creates intense heat at the point of welding.
A ‘filler metal’ is used in the process of welding the two pieces together, functioning almost like a solder, although there are many significant differences from soldering as well.
In a MIG welding machine, the electrode that melts the filler metal and the filler metal itself are the same thing.
The electrode steadily melts its own tip, as well as the surfaces of the pieces being welded, to complete the weld. This process would be extremely finite – with the electrode destroying itself completely in a few moments – if not for the fact that the electrode is actually the end of a huge spool of wire contained inside the welding machine’s main body.
This wire is steadily unrolled by automatic rollers, so that the electrode is replaced from behind at the same rate as its tip melts.
The hose that connects the welding gun to the main body of the welder does not simply carry this strand of wire – it also feed an inert gas like argon or a mixture of argon and helium to the nozzle.
This gas blows out constantly around the welding point, keeping away the oxygen that might oxidize or rust the metal in the welding pool in a matter of an instant or two.
Once the metal cools and hardens, it becomes immune to this, and the gas ensures that there is a clean, strong, high-quality weld left behind as the user moves the welding gun forward along the seam that is being fused.
Safety issue with the MIG welding machine
Although the MIG welder is very easy to use, it should also be treated with the respect that a device based around intense heat and a steady electric current deserves.
Eye protection needs to be worn to keep the retinas from being damaged by the infernal brilliance of the electric arc, while gloves are also essential.
Heavy, protective clothing is also a good idea, considering that arc welders can give a “sunburn” to the skin even through some lighter ordinary clothes.
Breathing the argon gas can be deadly if it manages to displace oxygen from the brain tissue, so some ventilation is prudent (although not enough to disrupt the shielding gas).
The equipment should also be checked regularly for damage or wear to prevent shocks from a frayed wire or loosened connection. With a few common sense precautions, however, a MIG welding machine is one of the easiest arc welders to use for an infinity of different projects, giving a decent quality weld with a minimum of experience.