Sheet Metal Forming: How It Works, Processes, and Uses
Sheet metal forming is a manufacturing process that fabricates metal parts from thin metal sheets. It is commonly used in everything from aluminum soda cans to aircraft components.
This article looks at the sheet metal forming process, how it works, where it is used, and its benefits and drawbacks. We also take a look at the sub-processes used to fabricate parts from the metal sheets.
Sheet metal forming, or sheet metal fabrication is the process of using metal sheets to form sheet metal components. This is achieved by forming and cutting sheets into the required shapes and forms using a variety of processes such as: bending, punching, shearing, and hydroforming among others.
Sheet metal forming is extremely common in manufacturing, and sheet metal parts can be found in a wide range of applications, such as: the automotive industry, aerospace industry, consumer goods, and household appliances.
The purpose of sheet metal forming is to create parts made from thin sheet metal for use in a wide range of applications. Sheet metal forming is an extremely versatile process that takes advantage of the strength and malleability of sheet metal to create durable parts that are lower in cost than comparable manufacturing processes such as forging.
Sheet metal forming makes use of a number of processes to transform a flat sheet of metal into metal parts that are durable and lightweight. Bending, shearing, punching, and hydroforming are all examples of processes that are used to form or cut metal sheets into the desired shape.
The tools for these processes will be set up according to the needs of the design, after which the sheet will undergo processing. Finally, a number of finishing steps will be applied. This might include: deburring, surface treatments, or welding.
Sheet metal forming is suitable for metal thicknesses of 0.6 mm to 6.35 mm. This is a general guideline, and the actual suitable thickness will change depending on the type of metal used, the manufacturer's capabilities, and the complexity of the metal part to be fabricated.
Sheet metal forming makes use of a wide range of equipment depending on the design of the part and the process being applied. The following list highlights some of the equipment used in sheet metal forming:
- Punches and dies are commonly used for shearing and cutting operations whenever specific shaped holes are required.
- Bending machines are used for bending operations.
- Rollers are used for shaping sheets into conical or cylindrical shapes.
- Shearing tools are used for shearing in a straight line.
Sheet metal forming involves a number of manufacturing processes. The following list contains some of the primary sheet metal forming operations:
Curling is a process that adds a circular, hollow roll to the edge of sheet metal. This is done to deburr the edges, but also to add strength and make the sheets safer to handle. Metal sheets are usually fed into specialized machines that gradually roll or bend the edges to form a smooth, rounded profile.
Curling is commonly used in HVAC, appliance manufacturing, and architectural applications to create edges on panels, trim, or housings. Most metals can undergo curling, depending on their ductility and thickness, including: steel, aluminum, and brass.
Curling adds strength to the edges of parts and improves rigidity and safety. Complex shapes or tight rolls can be challenging to achieve through curling. Specialized tooling and machinery may also be required to perform curling, depending on the application.
Laser cutting is a process of using a high-powered laser to cut shapes into sheet metal. A sheet metal blank is fastened onto the laser cutter machine bed. A computer numerical control (CNC) system controls the movement of the laser beam, performing precise, clean cuts in a pre-programmed pattern.
Laser cutting is used in applications that require precise shapes, patterns, or holes to be cut into sheet metal. It is commonly used in the automotive, aerospace, and electronics industries. Laser cutting can be applied to many metals, such as: steel, stainless steel, aluminum, or copper. Galvanized steel can be cut with laser cutting, but this is not recommended, as the high heat can lead to the protective coating being damaged, as well as toxic zinc-oxide fumes being released.
Laser cutting offers high accuracy, versatility, and repeatability. Minimal post-processing is needed, and there is minimal material waste. However, the initial equipment cost can be high.
To learn more, see our guide on Sheet Metal Laser Cutting.
Bending involves using bending tools in order to create bends or curves along a straight axis of the metal sheet. Press brakes are commonly used, into which the metal is set or clamped and then bent to the desired angle. Bending is commonly used for making automotive body parts, enclosures, and electrical components. The process is suitable for most types of metals commonly used in sheet metal fabrication, such as: stainless steel, brass, aluminum, and galvanized steel.
Sheet metal bending is quick, accurate, low-cost, and requires fairly simple tooling. Some disadvantages include limitations to the thickness of metal that can be bent, as well as the need for consistent thickness.
To learn more, see our guide on Sheet Metal Bending.
Ironing is a process used to improve the surface finish of sheet metal parts and achieve uniform thickness. A metal part is pressed through a die or series of dies which incrementally reduces clearance. By passing through the die, the walls of the part are thinned and elongated, without altering the shape significantly.
Ironing is used for producing aluminum cans, but also for other applications in which a consistent thickness and a good surface finish are required. Metals with high ductility are suitable candidates for ironing, including steel and aluminum.
Ironing improves dimensional accuracy, surface finish, and thickness uniformity in metal parts, but requires specialized tooling and machinery. It is also unsuited for parts that require significant shape changes.
Hydroforming is a process of shaping metals into complex forms by using high-pressure fluid. A metal blank is placed within a die cavity, whereafter high-pressure fluid is pumped onto the blank, forcing it into the shape of the die.
Hydroforming is commonly used in the automotive, medical, and aerospace industries, for which complex shapes are often required. Metals with high ductility are suitable for hydroforming, like: aluminum, stainless steel, and brass.
Hydroforming can create complex shapes with uniform wall thickness, with reduced waste and relatively low cost compared to other forming methods. Disadvantages of hydroforming include the specialized equipment that is needed, which requires a high initial investment, as well as the specialized expertise needed to perform hydroforming.
Deep drawing is a process used to create hollow cylindrical shapes. It works by placing sheet metal over a die and pressing the metal blank into the die cavity using a punch, resulting in a hollow cylindrical shape with no reduction in the thickness of the sheet metal.
Deep drawing is used for creating containers, beverage cans, and automotive parts such as door panels. The process can be suitable with any metals with high ductility and malleability. Aluminum, stainless steel, copper, and brass are commonly used in deep drawing.
Deep drawing allows for the creation of complex hollow shapes with consistent wall thickness and precise dimensions. It requires minimal labor and is cost-effective at high production volumes.
Shearing is a cutting process used to cut sheet metal along a straight line. The sheet metal blank is positioned on a shearing machine, which has two blades that slide past each other to cut the metal. The blank is clamped in place, and the upper blade of the shearing machine is lowered onto the blank to make the cut.
Shearing is used to cut metal sheets into smaller pieces or to trim edges. It is widely used in the manufacturing, construction, and automotive industries. Steel, aluminum, and stainless steel, along with most other metals can be sheared. The thickness of the metal and the capability of the shearing machine are the limiting factors as to what can be sheared.
Shearing is a rapid process, produces minimal waste, and is cost-effective at high volumes, but can cause edge deformation and burrs, especially in thicker materials. Shearing only cuts along a straight line, and must be combined with other processes to produce complex shapes.
Punching is the process of removing material from sheet metal to create holes, slots, or specific shapes. Sheet metal is placed between a punch and a die. The die supports the sheet metal, while the punch is forced through the sheet metal into the die to create the hole or shape.
Punching is also used for creating enclosures, brackets, and panels. Most metals can be used for punching, with the thickness of the sheet and the capabilities of the punching machine being the limiting factor.
Punching is an automated, rapid process. It has good repeatability and is a highly efficient process, especially for high-volume production. On the other hand, tooling costs can be high, especially for custom shapes. Some post-processing may also be required, especially for intricate designs.
Sheet metal forming can be applied to a wide variety of metals, depending on the application and specific properties required from the sheet metal part. Some common metals used in sheet metal forming are:
- Stainless Steel: Widely used in the medical and food industries. It has high strength, corrosion resistance, and good formability.
- Aluminum: A number of properties make it ideal for sheet metal forming, including good malleability, corrosion resistance, thermal and electrical conductivity, and an excellent strength-to-weight ratio. It is used in applications such as: household and industrial appliances, components for the aerospace industry, and in power lines.
- Hot-Rolled Steel: Relatively easy and cheap to produce. It is commonly used whenever price is more important than precision, such as structural components in the construction industry, automotive chassis components, and railroad tracks.
- Cold-rolled steel: Goes through more manufacturing steps than hot-rolled steel, which increases its tensile strength. It is usually used in home appliances, structural components, and the aerospace industry.
- Galvanized Steel: Durable metal with good corrosion resistance. It is commonly used in roof structure applications, air conditioning, and refrigeration.
- Copper: Very malleable, which makes it a good option for sheet metal forming. It has good electrical and thermal conductivity and is usually used for electrical applications.
Yes, galvanized steel can be used in sheet metal forming. It is commonly selected for its high durability and corrosion resistance, as well as its relatively low cost of production. Some common applications of galvanized steel parts include: roofing applications, air conditioning, refrigeration, and industrial machinery.
No, tool steel is simply not suitable for sheet metal forming. Tool steel is extremely hard and brittle, and it would break if subjected to the common metal-forming processes. Sheet metal forming relies on the ductility and malleability of metal sheets to form them into metal parts. Tool steels are generally hard with low ductility and malleability. This makes them less than ideal for sheet metal forming.
Sheet metal fabrication is extremely useful for a wide range of applications, as evidenced by how commonly the manufacturing process is used. Sheet metal forming is a relatively low-cost, extremely versatile process that can produce an almost limitless variety of parts.
Products made by sheet metal forming can be seen all around, in everything from beverage cans, household appliances, and metal furniture, to HVAC systems, structural components, and components for the aerospace industry.
Sheet metal forming is used in an incredibly wide range of industries, thanks to its versatility, relatively low cost, and the durability of the produced parts. Some industries that commonly use sheet metal forming are:
- Aerospace: Uses sheet metal forming due to the general precision of the forming processes, along with the high strength-to-weight ratio of the produced parts. It is commonly used for fuselages and structural components in aircraft and spacecraft.
- Automotive: Uses sheet metal forming for body panels, chassis components, and other structural parts of the vehicles. The durable, lightweight components produced by sheet metal forming make the method an ideal choice.
- Construction: Makes use of sheet metal forming to produce durable, weather-resistant components, such as: roofing sheets, structural components, and ductwork.
- Medical Equipment: Housings and enclosures for medical equipment, as well as medical devices, are commonly made by sheet metal forming, due to its ability to meet strict standards and requirements.
- Household Appliances: Sheet metal forming is commonly used for making enclosures, frames, and other structural components used in household appliances due to its versatility, precision, and durability.
Yes. The construction industry uses sheet metal forming for a wide range of applications. The relatively low cost and versatility of sheet metal forming, combined with the durability of sheet metal components make it an obvious choice for use in the construction industry.
Structural components such as: beams, columns, and brackets are made using sheet metal forming processes and are used for their high strength and load-bearing capabilities. Roofing sheets fabricated via sheet metal forming are used for their longevity and weather resistance. Ductwork for HVAC systems is commonly made using sheet metal forming.
Sheet metal forming has a number of advantages and benefits. Here are some advantages of sheet metal forming:
- Relatively inexpensive when compared to other manufacturing processes such as casting or forging.
- Very flexible in terms of design and application. Sheet metal can be formed in various ways with a wide variety of metals in order to produce a wide range of parts.
- Sheet metal parts are extremely durable, with good tensile strength and environmental resistance.
- Suitable for producing small batches, which makes it ideal for rapid prototyping.
- The use of thin sheets of metal makes sheet metal parts lightweight, while still remaining durable. This is ideal for applications in which a high strength-to-weight ratio is required.
Sheet metal forming does have some drawbacks. Here are some disadvantages of sheet metal forming:
- To start manufacturing with sheet metal forming, a high initial investment is required to acquire the necessary equipment and tooling.
- Very complex designs can be unsuitable for sheet metal forming and result in higher costs and production times.
- Sheet metal forming is a fairly labor-intensive process with many manual steps. This can make it slower than other processes such as stamping.
No. Sheet metal forming is relatively inexpensive and is known as a low-cost manufacturing process. The cost of sheet metal forming will change depending on the design of the part, the material used, and the number of processing steps involved. Fabrication costs can be kept low by sticking to fairly simple design elements and using standard sizes and options.
This article presented sheet metal forming, explained it, and discussed how it works and its processes. To learn more about sheet metal forming, contact a Xometry representative.
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