Sheet metal fabrication is one of the most valuable production methods used nowadays for creating a variety of functional components. Unlike other manufacturing techniques, it is a pretty extensive process that involves a series of steps and procedures that deal with sheet metal in different ways and produce robust parts.
This article focuses on the fundamentals of the sheet metal fabrication process. So, let’s have a look!
What is Sheet Metal Fabrication?
Sheet metal fabrication is a manufacturing process in which flat sheet metal pieces can be transformed into the desired shapes after designing, cutting, forming, and assembling them. Apart from this, fabricated parts run through different finishing techniques that offer a wide range of surface finishes.
Fabricators use a wide range of sheet metal materials to produce these fabricated parts, such as stainless steel, aluminum, steel, copper, brass, etc. These materials’ durability, conductivity, malleability, weight, and corrosion resistance make super strong and durable products. Usually, the sheet metal fabrication technique is used for manufacturing parts in the aerospace, automotive, energy, and robotics industries.
What Methods are Involved in the Sheet Metal Fabrication Process?
The following are some effective methods involved in shaping and manipulating sheet metals.
1. Designing and Programming
The first step you must aim for in the metal fabrication process is to design the product. The designing process includes many steps. The most crucial one is the idea of how you want your product to be. It mainly involves designing a 3D model of the required sheet metal part. Afterwards, industry engineers are supposed to develop blueprints that allow you to find the sheet metal specifications to make drawings. Finally, the drawings are rechecked multiple times by performing specific calculations.
Once the designing is done, the 3D CAD files are translated into machine codes that serve to control the machining operations. This process is known as programming.
2. Cutting Technique
As the name implies, this process deals with cutting metal sheets. Normally, the manufacturers take a piece of rectangular sheet metal according to the component’s design and cut it to a specific size and shape. Yet, the metal sheets can be cut in two ways.
|Cutting – Without Shear||● Laser Cutting
● Plasma Cutting
● Water Jet Cutting
|Cutting – With Shear||● Shearing
a) Cutting – Without Shear
To cut the metals without shear, several processes are used that involve heat, pressure, and vaporization. Let’s discuss the major types:
● Laser Cutting
The laser cutting process focuses the high-powered laser beam on a localized area to melt the metal, resulting in vaporizing the material. You can cut a wide range of metal sheets by adopting this technique, such as non-ferrous metals, stainless steel, and mild steel. However, some metals like aluminum might be challenging to cut by the laser cutting process.
● Plasma Cutting
Plasma cutting is a thermal process in which ionized gas is used to cut sheet metal. The high heat supply melts the material leading to rough cuts with burrs. Most commonly, plasma cutting is only effective on electrically conductive metals.
● Waterjet Cutting
The waterjet cutting process differs from the other two techniques as it uses a high-pressure stream of water for cutting metal rather than heat or temperature. The typical pressure offered by the waterjet cutting process is around 60,000 psi with a velocity of almost 610 m/s. This versatile cutting method allows you to cut hard and soft materials without any burrs or heat distortions.
b) Cutting – With Shear
Cutting-with shear is divided into four categories, shearing, blanking, punching, and sawing.
A metal fabrication process that makes cuts on metal sheets under the influence of a shearing force is called shearing. Primarily, this force separates the material from the specific point. The process is mainly used for cutting soft metals, including mild steel, aluminum, brass, etc. Make sure shearing is not a process for the ones seeking clean end finishes as it creates burrs and deformations.
Blanking deals with removing the portion of sheet metal from the larger material piece by using a blanking punch and die. The die is responsible for holding the sheet metal while the punch applies a blanking force through the metal. As a result, the material which is removed is the required product, while the remaining sheet on the die acts as the blank stock.
Punching is similar to blanking as it also uses shear force to create holes in the metal sheet. The only difference is that the removed metal acts as scrap material in this case, whereas the leftover material on the die is the final product. The primary function of punching is to produce a variety of holes having different shapes and sizes. Comparatively, punching is a faster and cleaner process than blanking.
Sawing is a different technique that uses a sawtooth to cut the materials. Generally, band saws are used for this purpose. The friction and shear force plays a leading role in separating the material chip from the metal sheets.
3. Forming Technique
Forming means shaping sheet metal into some specific structures and parts. Various processes play a role in the sheet metal forming step. Some major ones are discussed below;
Bending is one of the most used forming processes that deforms the metal by the application of force. Mainly, force bends the metal from a specific position at the required angle in order to attain some shape. The press brakes and rolling machines play a significant role in bending. Typically, press brakes utilize the punch and die to deform the metal sheet, while rolling machines roll the metal to different shapes. You may use different equipment to produce the U-bends or V-bends.
Rolling is a simple technique in which two rollers are used to press the sheet metal present in between them to reduce and uniform its thickness. During the process, the rollers constantly keep on spinning to produce the compressive force.
Manufacturers perform the rolling process in two ways, hot rolling and cold rolling. Mainly, cold rolling takes place at room temperature; however, hot rolling occurs above the recrystallization temperature of the metal. Pipes, tubes, discs, wheels, etc., are made by rolling.
Joining is a stage where manufacturers fuse the pieces of the workpiece using different techniques. Normally, the materials are joined together by welding, brazing, riveting, and adhesives. Yet, welding is the most popular one.
Everyone is familiar with the functioning of welding. Usually, it utilizes heat, pressure, or in some cases, both to join the metals. It works by melting the base metal with or without adding filler material. A firm bond is formed as soon as it cools. Fabricators can use various types of welding in the sheet metal fabrication process.
Riveting is also a joining process involving using different rivets or mechanical fasteners. During the procedure, drilling results in the formation of holes in metal sheets to be attached, and rivets are installed in holes. Once rivets are fixed, their tails are deformed.
Riveting is ideal for non-ferrous metals like aluminum and copper. Moreover, it is a reliable, cost-effective, and efficient joining technique. Yet, the addition of rivets increases the weight of the product.
The last step after completing the sheet metal fabrication process is finishing the components to enhance their appearance. Additionally, it also improves the surface quality of the material and makes it corrosion-resistant. Usually, fabricators use sandblasting, buff polishing, anodizing, or powder coating techniques to finish the end products.
What Materials Can You Consider for Sheet Metal Fabrication?
It is essential to select the best material for sheet metal fabrication in order to ensure the optimal quality of parts. Here are some materials you can use for fabrication:
- Stainless Steel: Stainless steel is famous for its corrosion resistance and formability. Stainless steel can be both non-magnetic and magnetic.
- Steel: The three types of steel also act as a fine material for fabrication, i.e., hot rolled steel, cold rolled steel, and pre-plated steel.
- Aluminum: Aluminum’s excellent strength-to-weight ratio makes it applicable to several manufacturing processes.
- Brass: Brass contains lower contents of zinc which makes it soft and easy to work with.
- Copper: Copper metals are best to prevent corrosion due to the protective oxide layers.
Hopefully, after reading the article, you’re pretty clear about the sheet metal fabrication process. Mostly, sheet metal fabrication is preferred due to its high strength and durability. On top of that, it is quite malleable, so you can bend it to several unique shapes without breaking or cracking. Many companies prefer to manufacture sheet metal fabricated parts over molded or cast components for the overall reduction in expenses and material waste.