Sheet metal fabrication requires specific forces to be applied to a piece of metal in order to change its geometry to a certain shape and thickness. When a certain amount of force is applied to the material, it causes it to deform to the point it can be stretched or bent in a wide range of complex shapes. The following are many processes that sheet metal forming includes:
This particular sheet metal fabrication process requires the application of force to the sheet metal in order to bend it at a certain angle and form a specific shape. The deformation is caused along a single axis, but if the operator wishes to, he can also perform multiple bends which result in a more complex part. When it comes to the bent parts, they can be small (like a bracket for instance), but they can also be large of up to twenty feet.
The process of bending a material results in both compression and tension in the sheet metal. Therefore, while the inside part of the sheet is going to shorten after being compressed, the external part will stretch to a certain length after experiencing tension.
When a piece of sheet metal is bent, due to the residual stresses in the material, the sheet will slightly spring back after it’s been exposed to a force that can cause it to bend. Because of this slight recovery, the sheet needs to be over-bent to a certain extent in order to achieve the desired bend angle and bend radius. The final bend angle is going to be smaller, while the final bend radius is going to be larger. The initial bend to the final bend ratio is referred to as the springback factor and the amount of it varies based on certain factors, such as the initial bend radius, the bend angle, the bending operation and the material bent.
In order to bend a sheet of metal, a special machine called a press brake is used. The press brake can be operated automatically or manually. In terms of size, press brakes are available in many sizes, ranging from twenty tons and up to two hundred tons, depending on the type of application they are used for. The press brake contains a die and a punch between which the sheet metal is located.
The sheet is placed over the die while the back gauge holds it in place so it can be punched and eventually bent. If the machine is an automatic type, then a hydraulic ram is used in order to force the punch into the sheet. The depth is usually controlled very accurately in order to ensure that the user achieves the right bend. Standard tools are generally used for the die and punch, which translates into a lower production cost.
On the other hand, in order to create custom bends, custom tools need to be used and these are always going to make the cost go up. The tooling material is selected by taking into consideration the bending degree, the material the sheet metal is made of and the production quantity. For more severe bending operations, harder sheet metal and larger quantities, stronger tools are required. To include some examples of tooling materials used for this process, they include carbide steel, tool steel, and low carbon steel.
Advantages of sheet metal fabrication
Sheet metal fabrication is not only one of the most common raw materials in the manufacturing industry, but it is also the basis for a wide range of low cost fabrication processes. Thanks to this process, many types of parts can be bent in a wide range of shapes. Compared to parts that need to be machined from block material, sheet metal fabrication uses a lot less material and is therefore more economical from this point of view. Better yet, combining sheet metal fabrication processes with other metal fabrication processes can result in a higher degree of flexibility.
Sheet metal is very well known for being used in a wide range of non-industrial and industrial applications. Some of them include:
• Office equipment
• Kitchen equipment
• Car trim parts
• Car body panels
• And many, many, more!