The amount of appliances in our daily lives that come from metal fabrication is massive, including tools, electronic appliances, cars, phones, and so on. Metal fabrication is a massively complicated process that has many different variations, each of those suitable for a specific goal.
We would go to each and every one of them, but first, we have to explain the basics of metal fabrication as a whole.
The definition of metal fabrication and types of fabricated products
As a process, metal fabrication is all about creating various metal structures using different processes using both manual labor and automation. Facilities that specialize in one specific field of metal fabrication are often called fabrication shops, and the products of said facilities are also often called fabrication. It is also true that some other types of metalworking, such as forging, casting, and metal stamping, are not considered fabrication, even though they can be similar in shape.
The most common types of raw materials for metal fabrication are sectional metal, welding wire, plate metal, castings, flat metal, fittings, and more. At the same time, it’s not uncommon for fabrication shops to employ multiple different experts in various fields, like blacksmiths, welders, boilermakers, and ironworkers, among many others.
That’s not to say that the only people employed in fabrication shops are directly related to the process of metal fabrication – there are also managers, team assemblers, solderers, first-line supervisors, brazers, cutters, welders, etc.
As for the types of products that can be created with metal fabrication – it is possible to separate all of them into three segregated categories. Each category has its own variety of processes used in the process of metal fabrication, or it can be just a single process altogether. Here are three main categories of metal fabrication:
- Structural. Mostly covers metal fabrication as a part of the building process, providing metal components to be used in various large-scale fabrication efforts, such as buildings, shops, skyscrapers, and so on.
- Commercial. As the name suggests, this mostly covers the commercial products, designed to be used by customers directly, be it appliances, cars, or something else entirely.
- Industrial. Specializes in creating products that are used as a part of other pieces of equipment – equipment that is used to generate consumer goods, for the most part. Some of the examples of industrial fabrication are ironworking machines and bandsaws, as well as many other ones.
The process of metal fabrication
It’s also not uncommon for metal fabricators to bid on jobs via drawing submission, and if the company gets the contract – they can start with the planning stage of a project, including ordering materials, programming machines for the job, and so on.
The actual creation of a product in accordance with a project is the following step, as soon as the entirety of raw materials arrives and the entire fabrication shop is ready. Some projects might require several processes to create a product in question – be it punching, forging, cutting, casting, shearing, or some other types of metal fabrication.
Additionally, there’s also another step in this whole process that is performed after all of the fabrication processes are done – and it’s called installation, which mostly includes partially or completely putting together the requested product.
Some other processes inside of a fabrication shop might just need to be something about finishing a product – it is a separated process that is secondary to metal fabrication and includes polishing, coating, deburring, painting, etc.
Types of metal fabrication processes
Metal fabrication consists of many different processes that may or may not be involved in the project depending on what needs to be done, as well as the material type and some other dependencies. You can find many different metal fabrication process types in the list below:
Now that we’re aware of what they’re called, it’s time to go over what each of those actually implies, starting with cutting.
While metal fabrication includes a lot of different processes, cutting is pretty much the most common one out there. The oldest example of a cutting process that can be replicated nowadays is sawing – but there are also many newer ones, using waterjets, lasers, and even plasma arcs to cut metal. The cutting methods can be drastically different, as well, including manual, power tools, computer-controlled cutting, and more.
There are also some cutting types that are extremely specific in the way the cut is performed. For example, there’s cutting with a die as the part that cuts off the necessary part of the material. This includes three general types of die cutting – the regular one, the rotary die cutting, and the flatbed die cutting.
While the regular die cutting process has been explained already – it’s using a die to cut metal, simple as that – two of the other examples are not as obvious.
For example, a rotary die employs a specific cylindrical die that spins around in one place to cut some specific parts of a material. There’s also a flatbed die – reserved specifically for tougher and thicker materials, this one uses a lot more force and flat surface than the other ones.
Folding is another process that is extremely simple in its concept – all you do is manipulate the raw material to bend it in the desired way. There are three main methods of folding in metal fabrication, and the most common one is with the help of a brake press.
The piece of raw metal is held between a punch and a die, and a punch is used to generate pressure onto the raw material to help it reach the desired shape. This kind of process is quite common for sheet metal shaping.
Additionally, there’s also a manual process of folding a material piece – which includes hammering it until the desired shape is reached – as well as with the help of a specific machine called a folder. The machine itself is quite basic, it has a flat surface with a clamping bar that holds a piece of raw material (sheet metal) in place, and also a front panel that forces the extended part of sheet metal to bend by lifting said front panel upwards.
Extrusion, on the other hand, is a somewhat more complicated process that focuses on making cylindrical items, mostly used either for piping or wiring purposes. This process uses a specifically crafted open or closed die to reduce the diameter of a raw material piece to match the size of the cross-section of the die and to form a cavity inside of a material piece by pressing around a die.
The most common shape of raw material for this operation is the form of a cylinder or a metal slug. There are also two variations of said operation: hot extrusion and cold extrusion.
Hot extrusion is using an increased temperature of the material to make it more likely to be molded in a specific shape and is mostly used for working with materials like copper or aluminum. Cold extrusion, on the other hand, is performed at room temperature and is often used for steel metal fabrication to make the product more durable.
Punching is a relatively simple process that uses specific machinery to create multiple holes in a piece of raw material. When the end product is the material piece with holes – it is used for fastening purposes. If the end product is a number of metal pieces that were forced out of the original piece of raw material, then this entire process can be qualified as blanking.
Stamping is somewhat close to punching, with the main difference being that stamping does not create a hole in the raw material piece, but creates a dent in a said piece. This is commonly used to generate various symbols on the surface of a material piece, be it letters, numbers, or images.
There are two main types of stamping presses out there right now – mechanical and hydraulic. In the majority of cases, stamping is performed on metal sheets with ¼ inch thickness or lower, and it creates an impressive range of products, including coins (a process called coining), smaller metal parts for electronics (four slide forming), and so on.
Casting is a process of pouring molten metal either poured into a die or a mold and then allowed to cool off to take the desired shape as a finished product. It’s pretty much a perfect process for making identical products using the same mold, particularly useful in mass-production.
Of course, there are different variations of casting, as well. For example, die casting uses a die as a holding place for a molten metal instead of a mold, and the shape of the final product is decided upon by the form of a die and by the amount of pressure applied to it.
There’s also a permanent mold casting, as in using a mold as the “storage” for the molten metal. The end product is stronger than with other types of casting, but it also makes it way harder to remove the mold after the product is done cooling and taking shape.
A different type of casting can theoretically fix the problem of removing the mold, called semi-permanent mold. It uses an expendable core in the mold to make the removal process far more simple than with permanent molds.
We’re finishing off with sand casting, in which your mold is represented by a pattern in the sand. This particular process is slower than the other ones, but it’s also somewhat more economical, and much more useful when intricate designs are needed.
Drawing is a process of pulling metal through a tapered die, and it’s used to stretch materials into thinner shapes. While the original process can be performed at room temperature, the piece of raw material can also be heated to reduce the amount of force needed to pull it through.
Another type of drawing when the end product’s depth is equal or more than its radius is called deep drawing, and it’s often used to turn pieces of sheet metal into either box-shaped or cylindrical vessels.
Forging is also a relatively known process, in which the piece of raw metal is struck by either a die or a hammer to reach the necessary shape – such work is called “applying compressive force”. As with any other process, there are some variations to forging.
The original forging process is performed at room temperature – this is cold forging. Using a temperature between “room” and just below the recrystallization process is called warm forging, and using the recrystallization temperature is, as you’d expect, called hot forging.
Machining is also a relatively simple process in concept, and yet there is a variation that can be found in it. By its nature, it is a process of removing excess material from raw metal pieces in some way. Three of the more well-known processes of machining are called milling, turning, and drilling.
Milling is a process of progressively removing excess material from the raw metal piece with special multi-point cutting tools. This process can be done both with the help of a specific CNC milling machine and manually, and milling, in general, is more often a secondary process than not. Some variations of milling can be plain milling, climb milling, form milling, angular milling, and so on.
Turning is another variation of machining that uses a specifically designed machine – lathe – to create a cylindrical-shaped piece by applying a cutting tool to remove parts of a raw metal piece that rotates in one place. The entire process can also be performed either manually or using the CNC turning machine, and the latter is used in cases when extreme precision of the process is paramount.
Drilling is the simplest one out of the three, and it’s just as the name suggests – it’s the combination of a drill and a rotary cutting tool used to cut holes in the raw metal piece.
Shearing is technically a variation of cutting, but it’s separated into a different category due to its unusual approach to the process. The result of shearing is one long cut that can be achieved by combining two tools – one below and one above the raw metal piece.
The cut is started by applying pressure to the metal piece with the upper part of a machine (shaped like a blade), which creates a fracture. By applying nonstop pressure to the fractured metal a cut is achieved, and the sheared edges can be burred afterward (burred as if the process of cleaning up the edges of the material pieces after the shearing).
Several pieces of metal can be combined into one just with the sheer combination of heat and pressure – this is a process called welding. It is quite a well-known method, mostly because of its versatility – it can combine pretty much any metal parts. There are four types of welding that are the most popular: FCAW, MIG/GMAW, SMAW, and TIG.
FCAW or Flux Cored Arc Welding uses a wire electrode with a core that generates shielding gas, which removes the need for a secondary gas source. Generally speaking, the nature of this type is similar to another type of welding called MIG – Metal Inert Gas Welding. It uses an external gas supply in combination with a solid wire electrode to prevent the metal piece from interacting with various environmental factors, making the process faster and more consistent.
SMAW or Shielded Metal Arc Welding is the most basic version of a welding tool, it’s an electrode stick that forms an electric arc when contacting with metal, and the high temperature of the arc’s impact is what welds the metal pieces together.
The last variation of welding that is more specific to heavier metals is TIG or Tungsten Inert Gas Welding. It utilizes a tungsten electrode rod that creates short arcs, more suitable for heavy fabrication. It’s one of the more difficult variations of welding and requires a highly-skilled professional to operate it properly, but it also works for the majority of metal-based products and comes in handy even for the most complex projects.
Metal fabrication is a relatively specialized topic, and it’s not uncommon for people to have misconceptions about the subject or a complete lack of information in the first place. This article is an attempt to combine some of the more basic information on the topic in one place, from the definition of metal fabrication to a myriad of processes that it can take the form of.