Metal fabrication is one of the most important processes in the manufacturing industry. For the metal to be altered into something useful it needs to be fabricated. The first step towards metal fabrication is the cutting of the metal. There are different methods to cut a metal varying from manual to mechanical processes. One such popular method of cutting metal is shearing. Metal shearing is a process where a sheet of metal is separated by applying great shearing force to it. In this article, we will discuss how the process of metal shearing really works.
The Shearing Machine
Basically, the process of shearing produces straight line cuts to separate any given piece of metal sheet. The machine which facilitates the shearing process is called power shear. It can be operated manually by labourers or can use advanced modes like hydraulic, pneumatic, or electric power.
How it works
The machine holds the metal sheet in the exact position so that it comes between the blades or with precise measurements. The upper blade or the punch and lower blade (the die) are not placed at the same position. There’s a slight difference or offset between them called the clearance. Normally, the lower blade remains stationary while the upper blade is pushed downwards forcefully. It is set at such an angle that the cut is made from one end to another, instead of at once. It reduces the amount of force required to cut the metal. Moreover, the blades don’t have a knife sharp edge; they have a square edge and can be of different kind of metals depending on the suitability for the given job. Given that the shearing process is highly dependent on the blades, you would do well to use highly quality blades like Amada shear blades or those from other top manufacturers.
The edge of the sheared metal forms a rough edge after the process as the blade is forced on the metal. It is because of the great stress that makes the metal fail and fracture forming burr edges. The amount of deformation depends upon the force with which the blades hit the metal and the clearance area, which is generally 5-40% of the total thickness of the metal but it largely depends on the kind of metal being sheared. The rough edges can be reduced if a die cushion is placed at the top of the metal sheet. On the other hand, it might worsen if there is too much clearance space between the upper and lower blade.