Sheet Metal Fabrication: The Definitive Guide
Custom sheet metal fabrication is an extremely valuable method of prototyping and product. If you need to create robust parts that are functional, such as brackets or enclosures, it’s vital to choose a set of fabrication processes that suit your budget and desired product.
Unlike other types of manufacturing techniques, sheet metal fabrication involves a number of different processes that manipulate and mold sheet metal in a variety of ways. These different processes can involve cutting sheet metal, molding it, or putting different pieces together.
Ready to learn everything there is to know about sheet metal fabrication? In this guide, we’ll break down what sheet metal fabrication is, the different processes involved, and how to choose the right process.
What is Sheet Metal Fabrication?
Sheet metal fabrication is the process of taking metal sheets and forming them into different shapes using a variety of different manufacturing methods. A product is usually made up of many different steps, from cutting to bending to punching. It all depends on the costs and needs involved in the project.
Most of the time, a product will require a number of different fabrication techniques to achieve a cohesive end result. For mechanical engineers and hardware makers, it’s important to understand all of the different fabrication processes and how they work.
In an informative guide of sheet metal parts for Machine Design, Greg Paulsen broke down the purpose and process of sheet metal fabrication.
“In sheet-metal fabrication, parts are formed from metal sheets by punching, cutting, stamping, and bending,” said Paulsen in the guide, “3D CAD files are created using a host of different CAD packages and then converted into machine code, which controls machines that precisely cut and form the sheets into the final parts. Sheet-metal parts are known for their durability, which makes them great for a wide variety of applications. Parts for low-volume prototypes and high-volume production runs are most cost-effective due to large initial setup and material costs.”
Not only is sheet metal fabrication a very useful and effective sector, but it’s also expected to hit major revenue in the next several years. In a news report for the Fabricator, Tim Heston estimated that the performance of the sheet metal fabrication industry will depend significantly on how many shops begin to embrace fiber lasers in the fabrication process.
“The 2021 forecast projects nearly $300 million to be spent on fiber lasers alone, and this doesn’t even include the more than $85 million expected to be spent on new and used CO2 laser cutting machines,” notes Heston in the report, “Fiber laser spending surpasses welding power source spending by millions of dollars. During the financial crisis, consumables led the spending categories, which seemed logical. It was a time to retrench, watch, and muddle through. 2021’s projections, however, fly in the face of conventional thinking. One would think that after a brutal 2020, fabricators would think twice before making a huge capital purchase. Nevertheless, large equipment investment continues.”
It’s clear that sheet metal fabrication is evolving and becoming bigger, and it’s also very much worth investing in.
Now that we understand what sheet metal fabrication is and the future forecast of its use, let’s dive into some of the most common types of metal fabrication processes.
Types of Metal Fabrication Processes
Fiber Laser Cutting
Fiber lasers are created by banks of different types of diodes. The light generated from these diodes are then amplified through a fiber optic cable. This amplified light is then collimated and focused by a lens onto a material that is to be cut.
Fiber laser cutting is a relatively new technology that is becoming more and more popular in the sheet metal fabrication world. This is because the delivery of the cut is very simple and can create a lightning-precise cut that is perfect for very small components.
Thermal cutting or laser cutting is an option for cutting sheet metal that is probably the most common or popular choice. That’s because it’s a very quick and efficient way to cut sheet metal with predictable, good results.
When using thicker metal sheets, thermal cutting may not be strong enough. In this scenario, plasma cutting will often be used for its strength and speed. However, you only reap the benefits of thermal cutting past 10 millimeters– laser cutting is usually the superior choice due to its excellent precision.
Shearing, also known as die cutting, is a process that cuts sheet metal without having to burn or melt it. This process is popular because it does not result in metal chipping. Think of it as cutting a piece of paper with scissors– that’s basically how mechanical cutting in sheet metal fabrication works.
For this process, a punch will press the workpiece against a blade or a fixed die. Without fitting through, the piece will shear easily. This is an excellent and affordable method to cut metal sheets into a variety of sizing. However, we’d still recommend laser cutting for more complex or precise cuts.
Punching is another popular way to cut holes into metal sheets. A metal punch essentially hits the metal sheet and causes a perforation. This method is ideal for larger-scale production of products, but it’s not a very affordable choice for smaller projects. That’s because this machine requires a secondary tool for additional types of cuts.
In sheet metal fabrication, press brakes are used to fold sheet metal parts. This is usually the hardest step in the manufacturing process simply because some bends are so complex. An engineer in a fabrication shop must know very well what the limitations of metal bending are if they want to create a product that’s actually producable.
Assembly is the ultimate step in fabricating a sheet metal product. During this process, welding and powder coating may be involved. Otherwise, parts will arrive powder-coated and will be joined together using other methods like riveting.
Powder coating is a very well-known type of surface treatment method for metal products that have been manufactured with sheet metal. Specifically, an electrostatic powder is applied to the charged metal part. Fabricators will opt for this method if the product has no additional special requirements, such as acidic applications, are needed for the completion of the part.
This process is used during the cutting process. It is essentially the process in which a part or shape is cut out of sheet metal and the remaining material is then discarded.
The is the process in which a protective zinc coating is applied to either an iron or steel product. This is done to prevent or reduce rusting on the product, as these two materials are very prone to rust.
Glazing is the process in which two metals are slide against each other to produce a layer of oxide. This can be a very beneficial process, as oxide is shiny and protective.
The forming and fabrication process will often involve using a custom die molding that uses pressurized fluid to shape metals. Such metals usually include steel, stainless steel, brass, copper, etc. This process is only really effective with softed metals.
Roll forming is the process in which sheet metal is constantly bent through rolls that will form the metal. Think of it as a big rolling pin that flattens the metal as it is fed through. This process can be applied to items other than sheet metal, such as coil, bar, and strips of metal.
Sometimes, sheet metal needs to be shrunk in the fabrication process. Tucking is the method of bunching metal together through mechanical force or a crevice with a spade hammer. This can also be done with a folding technique in which the sheet metal is bent around the edges with a tucking fork.
Tungsten inert gas (TIG) welding is a welding process that uses a tungsten electrode to produce a weld. This process involves using a two-handed arc and non-consumable tungsten electrode together.
This simple sheet metal fabrication process involves using a hammer and a dolly to pull the sheet metal apart.
Spinning is the process in which a piece of metal is rotated at very high speeds, thus forming it into a symmetric part using a CNC lathe.
Types of Metal Used in Sheet Metal Fabrication
Sheet metal can come in quite a variety of types. Fabrication processes are also designed to adapt to the metal being used. Some common types of metal include:
- There are so many different types of steel for all types of purposes, and this material is known for being the most durable and strong out there.
- This metal is much more lightweight, though it is still quite a strong metal to use. We recommend using aluminum for low-temperature applications, such as temperature control, food preservation, and aerospace.
- Copper is very easy to manipulate and is also electrically conductive, making it an excellent component for things like electronic development.
- This metal has a very low melting point and is a bit stronger than copper, making it ideal for cookware and currency applications.
- Brass is often used for things like small components. Fittings, and trimmings. It’s also quite light and resistant to corrosion, making it great for medical applications.
- Because magnesium is strong and boasts quite a low density, it is ideal for applications in which a stiff foundation is needed.
Tools and Machines Used in Sheet Metal Fabrication
The fabrication process wouldn’t get very far without a set of specialized tools for cutting, forming, and piecing together parts.
In most fabrication shops, Computer Numerically Controlled machines have become a common tool to use for fabrication. These machines are essentially computers that have been programmed to do custom repetitive tasks to align with the specifications set by the manufacturers. The precise nature of these machines makes them excellent for products extremely complex products, such as medical devices and other electronics.
For cutting sheet metal, shops will use a variety of saws. These include band, chop, and miter saws. Shops will also use cutting torches as well, as they can cut through big sheets of hard metal with minimal resistance.
Just as well, hydraulic breaks and different types of rolling machines are also used in the metal fabrication process. Oxy-acetylene torches are also used in the forming process. Breaks simplify the sheet metal fabrication process by creating bends at programmed angles. Rolling machines will help form steel sheets into rolls in order to create cylinders. An oxy-acetylene torch is used to straighten out warper steel during the fabrication process by applying heat to the metal in a slow and calculated fashion. This is an excellent way to remove significant warping from the metal.
Lastly, welding is at the heart of sheet metal fabrication. It involves assembling and tacking metal parts together to create a final product. There are so many different types of welding techniques that one can use in sheet metal fabrication in order to reduce warping and other defects.
Different Applications of Sheet Metal
Because sheet metal fabrication is so flexible as a process, it can be used in a majority of industries to create small and large components alike. A few industries that use sheet metal fabrication include aerospace, construction, HVAC, robotics, electronics, and much more.
Choosing the Right Sheet Metal Fabrication Processes
If you already have sheet metal parts designed and ready to go, there’s a good chance you already have an idea of the type of fabrication processes that would best fit your design. Many CAD utilities out there make it possible to create product features that align with actual sheet metal manufacturing processes.
How was our guide to everything you need to know about sheet metal fabrication as a mechanical engineer or hardware maker? Tell us what you think in the comments below!