A Breakdown of the Sheet Metal Fabrication Process

An HVAC system is a complicated assembly that relies on many parts working together flawlessly. Since every Louisville home or business is different, every system requires an individualized approach. Having an HVAC system that’s tailored to your needs can help keep energy costs in check. Using sheet metal fabrication and components can also make new construction projects easier.

Of course, installing a custom system means you can’t always grab parts off the shelf. The solution is using sheet metal fabrication to create the perfect parts needed to do the job. Fabrication is especially useful when it comes to designing custom plenums and ductwork. The typical system loses up to 30 percent of its conditioned air through leaky or poorly designed ducts. Ducts that are custom-fabricated, however, are built to deliver excellent performance and efficiency. So, how does the sheet metal fabrication process work?


Unsurprisingly, sheet metal fabricating typically begins with a large sheet of galvanized metal. This sheet is then measured and marked according to the purpose it will serve. Fabricators then cut the metal to the desired size using a variety of tools. This process is also called shearing because it involves applying great enough force to cause the metal to shear. Sheet metal cutters and shears are often used at this stage. Other tools include powered and non-powered saws, chisels and torches. CNC plasma cutters are also frequently used to produce quick and precise cuts.


Once the sheet metal pieces are cut to the right size, the next step is forming them to the desired shape. Each piece must have a specific shape depending on its function and location within the larger system. Some shaping can be done by using hand tools, but mechanical equipment is often required. A fabricator has many tools at their disposal to help them achieve exactly the shape they need. Here are just a few of the tools that may be used during fabrication:

  • Folding machines are used to fold sheet metal at sharp and precise angles.
  • Flange forming machines press flanges into sheet metal to make joining easier.
  • Notching machines can shear sheet metal at precise angles to create corners.
  • Pneumatic corner mounting machines are used to form corners from rectangular ducts.
  • Shrimp bending machines bend pipes and ducts to create elbow-shaped “shrimp” bends.

No matter the tool, the basic goal of forming is to apply enough pressure to deform the metal without shearing. The forming process is where flat, cut sheets of metal are transformed into the parts needed for the job. Fittings and other necessary pieces are also formed at this stage.


Once all the necessary pieces have been formed, the final task is to put them all together. This stage is particularly important to ensure that every piece works as intended. A single misaligned duct section or poorly installed plenum can hamper an entire HVAC system. The assembly stage is also the time for any final adjustments to maximize fit and efficiency.

The actual process of assembling varies depending on the application. In many cases, the pieces are joined together by welding. Other applications may use threaded fasteners, rivets, powerful adhesives or some combination of the above. In other cases, pieces may be joined together by crimping specially made seams. Some assemblies may also require a final step called finishing. This typically involves applying a durable powder coat treatment.

A well-designed HVAC system is an important component of any Louisville home or place of business. A system that’s tailored to meet your specific needs can lower utility costs and save a lot of headaches long-term. Sheet metal fabrication is an essential part of ensuring the perfect fit and function. To learn more about how you can benefit from HVAC fabrication and design, check out Birkhead Co.’s professional HVAC services or call to speak with a helpful representative.

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