A Manual for Sheet Metal Fabricating Techniques, Including Cutting, Bending, and More

Sheet metal fabrication is a valuable production method for making robust functional parts like panels, brackets, and enclosures.

Contrary to other manufacturing methods, sheet metal fabrication actually entails a variety of procedures that all affect the metal in unique ways. The sheet metal may be cut, shaped, or sections of it may be joined together during these various procedures.

This guides look at the main sheet metal fabrication processes and explains how they work and what they are used for.

What is sheet metal fabrication?

Sheet metal fabrication is a set of manufacturing processes for turning sheet metal into functional parts. For this guide, we have divided the processes into three categories: cutting, deformation, and assembly.

Steel, stainless steel, aluminum, zinc, and copper are typical sheet metals, and their gauges typically range from 0.006 to 0.25 inches (0.015 to 0.635 centimeters) thick. While thicker gauges might be more suited for heavy-duty parts with demanding applications, thinner gauges are more pliable.

For partially flat or hollow parts, sheet metal fabrication can be a cost-effective alternative to processes like casting and machining. The process is also quick and produces minimal material wastage.

Sheet metal fabrication is widely used for industrial and consumer parts and in specialist industries like automotive, aerospace, energy, and robotics.

Sheet metal fabrication: Cutting

Cutting is one of the three primary manipulation techniques for sheet metal. Due to the ease with which useful pieces can be produced by only removing small amounts of material, sheet metal fabrication can be viewed as a subtractive manufacturing process (much like CNC machining).

Manufacturers can cut sheet metal using a variety of different pieces of machinery, some of which are unique to sheet metal fabrication.

Laser cutting is an important method for cutting sheet metal. A strong laser is used in a laser cutter that has been magnified by a lens or mirror. Although it is a precise and energy-efficient machine, it might have trouble penetrating the hardest materials. It is best suited for thin or medium gauge sheet metal.

Water jet cutting is an additional method of cutting sheet metal. A high-pressure jet of water combined with an abrasive material is used in water jet cutting, a technique for fabricating sheet metal, to cut through the metal. Since water jet cutters don't produce heat that could unnecessarily deform the metal, they are especially helpful for cutting sheet metals with low melting points.

A third sheet metal cutting option is plasma cutting. A plasma cutter creates an electrical channel of ionized gas which forms a jet of hot plasma that easily penetrates even thick gauges of sheet metal. Although less accurate than laser or water jet cutters, plasma cutters are fast and powerful with low setup costs.

These three cutting machines can be used on other materials besides sheet metals, but there are some techniques used solely for sheet metal fabrication.

For instance, while punching (sometimes referred to as piercing), precise holes are made in sheet metal using a punch and die. Between the two parts, a sheet of metal is inserted, and the punch pushes through the metal to the die. The circular pieces of material that were removed during the punching process are turned into garbage, but they can also be used to create new workpieces, a process known as blanking.

When creating many holes, similar equipment can be used for the perforation of the sheet metal.

Sheet metal fabrication: Deformation

Another major category of sheet metal fabrication processes is sheet metal deformation. This group of processes contains myriad ways to change and manipulate sheet metal without cutting into it.

One of the main deformation processes is sheet metal bending. A sheet metal manufacturer may bend sheet metal into V forms, U shapes, and channels at angles up to 120 degrees by using a device known as a brake. It is simpler to bend sheet metal with thinner gauges. Decambering, a process used by sheet metal manufacturers, allows them to do the opposite, taking the horizontal bend out of strips of sheet metal.

The process of stamping is another deformation process, but it can also be thought of as a subcategory of its own. It involves the use of a hydraulic or mechanical stamping press equipped with a tool and die, and its operation is similar to punching — though the material does not necessarily have to be removed. Stamping can be used for specific tasks like curling, drawing, embossing, flanging, and hemming.

In contrast to other deformation methods, spinning is a sheet metal production process that rotates the metal while it is forced against a tool. The procedure is helpful for producing rounded sheet metal objects, such as cones and cylinders, and has an appearance that is comparable to CNC turning or even pottery spinning.

Less common sheet metal deformation processes include wheeling, which is used to make compound curves in sheet metal, and rolling, in which sheet metal is fed between a pair of rollers to reduce its thickness (and/or increase consistency in thickness).

Some procedures fall somewhere in the middle of cutting and deformation. For instance, to expand a sheet of metal, several slits must be cut into the metal, and the sheet must then be stretched open like an accordion.

Sheet metal fabrication: Assembly

Sheet metal cutting and deformation are two ways of forming sheet metal. A third way is assembly, either by using common fasteners or by other methods.

The assembling of various sheet metal elements using fasteners like bolts, screws, and rivets is an essential step in the manufacturing process, even if it isn't always seen as fabrication. Puncturing is one of several sheet metal fabrication techniques that can be used specifically to create holes for rivets and other fasteners.

Sheet metal components may also be joined together using the process of welding, in which heat is applied to melt a section of the metal where it joins with another component. The two components' melted metal fused together to create a reliable connection. Although different metals may weld better with specific forms of welding, like arc, electron beam, resistance, etc., common sheet metals like stainless steel and aluminum have superior weldability.

Selecting the appropriate sheet metal production techniques

You probably have a solid concept of the fabrication procedures that will be applied to actualize the design if you have already designed sheet metal parts. In fact, some CAD tools let you create features that correspond with real-world sheet metal manufacturing processes like bending and stamping, such as Autodesk Fusion 360 and Dassault Systemes Solidworks.

Regardless of your level of experience, the sheet metal experts at Metalli can help you finalize your designs and choose between similar processes like laserjet cutting and water jet cutting.