What Is Sheet Metal Fabrication
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- Sheet Metal Fabrication, Fabrication, Manufacturing
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What is sheet metal fabrication, what are the stages of the sheet metal fabrication process? In this article we answer both of these questions and more.
What is sheet metal fabrication?
Sheet metal fabrications involve various stages that allow engineers and professional sheet metal fabricators to turn sheet metal materials into a functional part that they or others can utilise to create a product, kitchen accessories and home appliances. The basic process entails three essential steps, known colloquially as bending, cutting and punching sheet metal.
Initially, 2D and 3D drawings and models are created using sketches and CAD software, which is later converted from a CAD file into machine code that its mechanical properties will understand. Once these machines are set up, they will precisely shape the sheet metal to match the client's product requirements, using a combination of the bending, shear cutting sheet metal or punching processes. These machines and tools include rolling machines, CNC machines, hole punches, and cutting torches.
Any parts manufactured using a specific sheet metal piece must have a uniform material thickness to its design limitations. Typically, any sheet metal will have a thickness of approximately 0.5 - 6mm; anything that tips more on the thicker side is then considered a metal plate. You can manufacture thicknesses of around 20mm. Sheet metal fabrication is usually known for its immense durability and ability to curate high-volume productions and one-off prototypes.
The Stages Of Sheet Metal Fabrication
Each fabrication project differs from the next; however, all sheet metal manufacturing has similar stages used to construct the various products and consumer goods, such as storage tanks and durable and light casings. These stages involve the following:
The designing process is the beginning of the fabrication journey, and each company will broadly approach the design process in their unique way. At some manufacturing factories and workshops, clients will be offered the opportunity to provide their specifications regarding the design at the very start of the working process.
Clients can opt to work diligently alongside a team of skilled engineers who can help tweak the designs before they are manufactured, which is the most cost-effective outcome. Such is an integral aspect of the fabrication process as it can help you effectively determine the best manufacturing approach and the economic efficiency of your project.
Throughout the designing stage of the additive manufacturing processes, you want to ensure you are always in close proximity to a trained and experienced CAD professional (Computer-Aided Designer), as they are vital when striving to create a final product with high specification.
After your design has been officially formalised, engineers will translate these designs into a design that is universally understood by the machinery utilised in the workshop to help curate these products.
Such operation is known as the programming process, as during this period, engineers will draw up parts that will later be nested into 2D form sheet metals. Nesting refers to a procedure involving laying out cutting patterns, which minimises raw material waste, ensuring your sheet metal material is maximised to the fullest.
Once engineers and fabricators have set all their machine programs to work, they begin the cutting process. They can choose a large variety of cutting methods, such as water jet, laser cutting, plasma cutting, etc. Saws, including band saws, chop saws and miter saws, can be helpful; however, most methods are far more powerful.
Professionals use plenty of brazing equipment such as hand-held torches, induction heating systems and furnaces to obtain the heat and high temperatures they need to cut sheet metal.
One of the industry's most accurate metal sheet cutting methods is laser cutting. Laser beams use a specifically programmed design and cut your material selection with great precision and ease in straight lines as opposed to a staggered manner.
Numerous components need particular forms or perforations, for example, countersinks, ribs or louvres, to complete various sheet metal applications around a property or site.
When adding holes or slits in the sheet metal, engineers will use a CNC punching machine with its array of tools that meticulously hit, shape, or perforate your sheet metal.
Engineers and welders refer to it as CNC folding, yet it is more commonly known as the sheet metal bending process. It is a fabrication procedure consisting of a broad range of machines, for example, an automated panel bending machine and a manual press brake.
Depending on the complexity or size of your part, it may require the use of robotic bend cells. Each machine you involve in the process will gradually form the part you need through clamping your chosen sheet metal between the V-die and top tool.
Once this has been achieved, professionals will apply extreme pressure to obtain the desired curvature and necessary bend radius for the product or component they wish to develop.
There is an incredible range of welding techniques and tools such as oxy-acetylene torches and stout fixtures for working with sheet metal if you have the skills, environment and qualifications to do so. Tack welded metal is perfect for temporary or small welds that still require later welding.
These methods include TIG welding, robotic welding, MIG welding, spot welding and projection welding. Engineers use these welding forms and specific tasks to achieve different outcomes or the same outcome with different materials.
The assembly aspects of metal fabrication vary wildly depending on your final product's complexity. It can range from a simple weld with easier forming to a complicated weld with various electrical integrations such as PAT testing, hardware installation, and wiring looms. Sometimes the assembly contains structural and machinery adhesives to ensure you gain your desired form in the cooling process.
Regardless of your product's line of work, the same quality and precision are always given. However, some industry's fabrication issues require more attention when it comes to their final assembly, for example, the transportation industry. Occasionally, you may encounter some assemblies that need insertion during this stage. Insertion involves pressing nuts, studs and other fastening components, which can lengthen the duration.
The steel or mild steel many engineers utilise to create hot-rolled metal sections is curated from recycled scraps and is most suitable for shaping and machining. Yet, it reacts with various agents in the atmosphere, such as heat-compressed gases and reverts to its original state, which is why it is essential to ensure you're not carrying out these tasks in corrosive environments.
Powder coating is the process of thoroughly applying electrostatic powder onto an ultimately charged metal component and, after doing so, curing the unit at a specific heat so that the coating will be durable.
At most engineering workshops, they tend to utilise a high-quality automated powder coating plant. A powder coating plant uses a procedure consisting of Oxsilan pre-treatments, drying and powdering the metal and finally, stoving.
Types of sheet metal fabrication
Sheet metal fabrication is an incredibly in-depth process that goes through numerous stages and uses many different techniques and methods to get the right or different grades of cuts, desired shapes and models fit for different products, and parts for larger structures.
There are different ways of cutting, bending and assembling different mediums of varying thicknesses. Here are some examples of the types of sheet metal fabrication and the processes they go through:
Laser cutters are one of the key methods for cutting up sheet metal or puncturing it. Laser cutting is known for its use of high-energy focused beams intensified with a mirror or lens that helps vaporise or burn the material and form precise cuts in the flat sheets.
Engineers and welders in the industry highly recommend laser cutting for those searching for a rapid and precise cutting technique to cut sheet metal without the risk of warping happening to the medium they are working with.
Visual defects are significant for the product's or part's aesthetic or functional value. Its reduced chances of warping are down to the small heat-affected zone when the laser hits the material; the heat doesn't spread across the whole sheet and stays predominantly in the area you wish to cut.
Straightening warped steel is a doable task; however, it will ultimately lengthen the fabrication process, so find the most precise method within your budget and use that. Fibre lasers and C02 are typically utilised to cut material of around 10mm thickness, making the device incredibly versatile.
Water Jet Cutting
Another standard sheet metal cutting method that engineers and welders use is referred to as water jet cutting. Water jet cutting uses an incredibly high-pressure jet device that mixes an abrasive substance with a strong jet of water that helps form cuts in your metal material.
Water jet cutting is often preferred compared to other material fabrication techniques like laser cutting as it provides a low melting point for aluminium and plastics that tend to have a low density compared to most metals.
High melting points could potentially reach a stage where the medium becomes deformed due to the extreme heat; however, low melting points prevent any unwanted deformation.
The following sheet metal cutting method is one of the most potent methods in the industry, known as plasma cutting. Plasma cutting is used to cut through stainless steel sheets, and it works by creating an incredibly hot electrical channel.
The electrically ionised gas, or plasma, helps to melt the material in a specific way that forms a cut. It's a highly effective material cutting technique tool, especially for any sheet metal with a thickness of over 10mm.
You should be wary if you use plasma cutting for anything that must be cut accurately. The cut's precision using sheet metal fabrication techniques is not at the same level as water jet cutting or laser cutting, as these gain more accurate dimensions.
Sheet metal guillotines are another incredibly effective metal fabrication technique that allows professionals to create precise, clean cuts through sheet metal of various kinds. During the guillotining process, a metal sheet is carefully fed through two blades and eventually compressed as one with a high-pressure force.
Such pressure helps deform the thicker sheets until they produce a sufficient high-quality cut. Unlike a few other methods that are used just as frequently, guillotining is inexpensive and is quick to produce effective, efficient cuts; however, you must beware that this method can leave your metal with some deformed edges.
Most fabrication mistakes cab be easily remedied, yet they tend to make the process a little longer, so if you have a more extensive budget, we recommend a different method.
Sheet metal punching is a standard fabrication method that utilises a relatively similar cutting mechanism to that used in guillotining. However, unlike the guillotining process, punching uses a die, a shaped metal tool, to successfully make cuts.
Engineers will force the die into the sheet metal at an extremely high speed that will pierce the sheet. In the industry, plenty of commonly utilised dies come in various standard shapes, for example, squares, rectangles and circles, yet many professionals can curate high-quality custom tooling to punch more complex shapes into various metal sheet materials.
Punching techniques are ideal for high-volume production, as manufacturing the die tools can be relatively costly.
Bending is another fundamental aspect of fabrication and other manufacturing processes. It allows professionals to create sheet metal into functional products and parts, implementing them across numerous industries and lines of work.
Engineers can bend sheet metal using high-quality devices and machines known specifically as press brakes; these contain lower blades and tools referred to as the V-die and an upper tool known as the punch. Professionals place the material between these two tools and operate it so that the punch presses down with an immense force into the V-die tool, which forms a bend in the material that many can utilise.
Bending can help you create various shapes, including V-shapes, U-shapes and shapes across a straight axis. The angle of the bend is typically determined by the depth at which the professionals press the punch tool downwards into the V-die.
Cutting and bending are two of the most common ways professionals can begin roll-forming sheet metal to utilise during fabrication; however, the third way is to assemble it. Engineers can assemble sheet metal components using a variety of mechanical fasteners, such as rivets, bolts and screws.
Alternatively, professionals can join them with various welding processes and adhesive use, typically involving two or more sheet metal parts welded and fused with the help of pressure or immense heat. After cooling down, these parts will have successfully formed a tight bond.
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