Guardrails as a metal forming product.

The Ultimate Guide for Sheet Metal Forming

Oct 31, 2023 | custom fabrication

Metal forming is one of the world’s most widely used manufacturing processes and is responsible for creating everyday items we wouldn’t want to live without, like fishing rods, golf clubs, wrenches, hinges, screwdrivers, and much more.

Designs for sheet metal fabrication products can get complicated quickly. There is a lot that goes into a forming project and it can be easy to misunderstand the requirements for the design.

This guideline will help you understand the general capabilities of metal forming. With this guideline, you will be better suited to design a project that will be successful from start to finish. No matter how flawless the design may seem, it is always best to consult with your metal fabricator before getting too far into the project. This article will also help you eliminate design mistakes before sending parts to your fabricator.

The Basics of Metal Forming

Metal forming is a process in which metals are shaped and manipulated to create a desired form or geometry. To achieve the desired shape, size, or structural properties, fabricators will use mechanical, thermal, or combined methods.

The exact capabilities of a specific fabricator will range from one to the other. It will depend on the machinery they possess, technological investments, expertise, and communication you have with them.

You can bend, stamp, roll, form, or change metal in many different ways, but it’s important to make sure you use the correct method for your project.

That’s where working with a fabricator can help.

What are the Main Materials that can be Formed?

Since metal forming is a versatile process, there is a wide range of materials that can be used and formed. Here are the 6 most common types of materials that are formed:

  1. Aluminum
  2. Brass
  3. Copper
  4. Stainless Steel
  5. Steel
  6. Galvanized Steel

General Guideline for Sheet Metal Forming

While we will work with clients to try and make any project happen, there are some general forming capabilities that we go by to make sure a project is possible. 

  • Standard forming tolerances (tolerances increase as thickness and part size increases)
    • 3 place decimals ±0.015”
    • 2 place decimals ±0.030”
    • 1 place decimals ±0.060”
  • Inside Radius is generally same as the material thickness for air bending
  • Minimum flange length is generally material thickness X 5
  • OD dimensions on drawings are easiest for operators to program with and to check the flat blank length.
  • For best results, Aluminum lasered and formed parts should be 5052 series.
  • Think about sheet size when adding bends to parts, to save cost make sure blank sizes fit in standard width material; 48″ or 60″.
  • Holes on or near bend lines will have distortion. If possible, keep holes material thickness x5 away from bend lines.
  • All of the above tolerances are general guidelines, they can all be manipulated better or worse on a case by case basis. Prices increase with complexity
  • Missing information on drawings is the biggest challenge faced in a job shop setting.
  • The drawing should relay the design intent. For example, if the part is a guard that must mate up to another part, the mating dimensions should be the ones that have the tolerances associated with them.
  • All details that can be added to the part level model should be, adding holes in the wrong level of a SW model causes manufacturing problems

The 9 Main Types of Metal Forming

  1. Bending: Bending is the deformation of a metal piece to create specific shapes, angles, channels, curves, and other structural elements, usually with the help of a press brake machine. Press brake machines use force to sandwich the metal between the punch and the die to create a desired shape. 
  2. Forging: Forging is one of the oldest methods of metalworking. It involves applying compressive force to a metal in order to shape it. The metal is typically heated before this, to make it more malleable. Types of forging include:
  3. Extrusion: Extrusion is a forming process in which a cylindrical billet is pushed inside a closed cavity, the end product is called an extrudate and is pushed out using either a mechanical or hydraulic press. 
  4. Rolling: Rolling, also known as roll forming, is a metal forming process where metal is fed through one or more rollers to reduce the thickness of the metal. 
  5. Cutting: Cutting is a method where there is a separation of metal, also known as cutting, where excess material is removed using different tools. 
  6. Stamping: Stamping, also known as pressing, is when a flat sheet of metal is placed into a stamping press and the press uses a tool and die surface to form the metal into a desired shape.
  7. Casting: Casting is a process in which molten metal is poured into a cast, or mold, and is formed. Once the metal and cast cool, the metal is extracted and machined and finished.
  8. Hydroforming: In hydroforming, a metal sheet is placed over a die and then highly pressurized water will force the metal down and make it conform to the shape of the mold. There are two types of hydroforming: Sheet and tube hydroforming. 
  9. Machining: Machining, also known as subtractive manufacturing, is the metal forming process in which a piece of raw material is cut and it creates a desired final shape and size.

How to Get the Part you Need, When you Need it

Metal forming is one of the most commonly used manufacturing techniques and our day to day lives wouldn’t be the same without products created from metal forming.

Metal fabricators all have different metal forming capabilities. Some may specialize in one field, but not do any work in another.

So what is the way to find the fabricator with the forming capabilities you need? Reach out to our friendly staff here at Impact Fab, and let us help you get your project started.