Sheet Metal Fabrication Process: Understanding the Basics

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Usually, those who operate outside the core industry have no knowledge and experience in the sheet metal fabrication process. Such individuals are typically unaware of the jargon, procedures, and project requirements and merely lack a fundamental insight into each phase, process, and several methods involved in fabricating sheet metal.

But it is incredibly vital to develop a holistic understanding of a new manufacturing facet before even thinking about working on a project.

So, here is a beginner’s guide to sheet metal fabrication fundamentals and the most well-known fabrication methods employed in the industry. 

What is Sheet Metal Fabrication?

The term “sheet metal fabrication” describes the process of transforming flat metal sheets into metal products and structural designs. Most sheet metal processing techniques include converting various sheet metal types into components and parts by employing precision equipment like a CNC machine and several forming methods.

These techniques typically complement each other to create the required product with utmost dimensional accuracy and best-in-class aesthetics.

Typical sheet metal fabrication procedures include cutting, bending & forming, joining, and finishing. A broad spectrum of metal materials, including steel, aluminum, CRES stainless steel, copper, and brass, are appropriate for sheet metal fabrication. Hence, numerous products, including household appliances and smaller components like brackets, frames, and casings, can be produced using this technique.

Four Prominent Methods in Sheet Metal Fabrication

1. Cutting

Based on its thickness, the metal requiring fabrication chiefly comes in the shape of a rectangle plate or sheet. Therefore, appropriate cutting of the sheet is the initial step in fabrication. There are two main ways to achieve this:

a) Cutting with shear- It involves three distinct procedures with each playing a unique and essential function:

  • Punching
  • Blanking
  • Shearing for metal cutting

b) Cutting without shear- Big-volume industrial projects requiring metal fabrication demand this technique precisely. It facilitates better processing times and optimal precision cutting.

The three techniques used in this process are perhaps the most effective at producing precise cuts:

  • Laser Beam Cutting
  • Waterjet Cutting
  • Plasma Cutting 

2. Bending and Forming

Metal sheets bending occurs using a multitude of machines and tools. U-bends, V-bends, and other forms required in a project’s designs and blueprints get executed using rolling machines, press brakes, and other tools.

sheet metal bending

It is a crucial phase as the primary metal design shaping and modification occurs at this juncture, regardless of how these bends are made—through stamping, machining, or folding.

Regardless of how streamlined the bending operation appears, this relatively complicated procedure requires a highly trained expert. It’s because of a phenomenon known as “spring back,” which implies how metal constantly seeks to recover its flat form after bending.

So, operators need to overbend the piece so that the spring-back angle achieves the proper inclination to solve this problem.

3. Joining

Any slack, in-contact ends must weld together once the sheet metal receives machining and shaping into its desired form. During sheet metal fabrication, you can join the edges or sides in several ways.

The most popular technique is welding, but differing project requirements may call for other techniques like:

  • Riveting
  • Brazing
  • Adhesives.

Also, welding demands highly trained experts to reduce safety concerns and provide a thin but precise join line.

4. Finishing

Finishing is the last step in the sheet metal fabrication process. A surface finish should always apply to the entire product once the metal has already been cut and shaped, complying with the project’s specifications.

metal finishing process

It changes the final sheet metal product from having a rustic appearance to a cleaner and more accurate one. Finishing frequently entails the application of:

  • Silk screening
  • Paint powder coatings
  • Sealants and other protective coatings

Moreover, supplementary finishing processes can also occur to enhance the sheet metal’s preexisting characteristics, such as better conductivity or resistance.

Top Design Considerations for Sheet Metal Fabrication Process

1. Bend Radii

Maintaining a sheet metal’s internal bend radius at least as large as its thickness is critical.

2. Wall Thickness

Any geometry needs to have a consistent thickness. Sheet metals with varying thicknesses would be required for geometries with multiple wall thicknesses. As a result, accurate part alignment and positioning may be problematic.

3. Orientation of Slots and Holes

The diameter of slots and holes needs to be least equal to the sheet metal’s thickness. Hole spacing should also be appropriate. Never allow them to get too closer to the metal’s edge.

4. Bend Allowance and Deduction

To produce a flatter pattern-

  • Bend allowance is a material that must be added to the precise lengths of the components.
  • Bend deduction is a material that needs removal from the flanges’ length.

In Review

Fabricating sheet metal involves both expertise and technology. A qualified metal fabricator will be necessary if your project ever necessitates formed sheet metal due to the various processes and subtleties involved.

Hence, a comprehensive understanding of various attributes involved in sheet metal fabrication is a must for CNC experts.

About the Author:

A photo of a worker on a construction site wearing a hardhat and a reflective vest.
Peter Jacobs is the Senior Director of Marketing at CNC Masters

Peter Jacobs is the Senior Director of Marketing at CNC Masters. He is actively involved in manufacturing processes and regularly contributes his insights to various blogs on CNC machining, 3D printing, rapid tooling, injection molding, metal casting, and manufacturing in general.