Why Do We Straighten Sheet Metal?
Straightening sheet metal is a process designed to make the subsequent machining process run more smoothly. It uses external forces such as heat or pressure to modify the sheet metal so that it takes the correct shape. Usually, there are two situations where sheet metal needs to be straightened, one at the beginning of the process and the other when it needs to be straightened.
It is well known that sheet metal originally comes from coils of metal. Usually, the sheet metal is collected and serves a great purpose in order to facilitate the transfer or whatever. Uncoiling the sheet metal and making them as flat as possible would be the first thing to do as the next step before any work is done with it. Sometimes sheet metal can be deformed, for example by being uneven, bent, twisted, wavy, or otherwise distorted.
Well-straightened sheet metal can be used as raw material for stamping, punching, or cutting processes such as milling or drilling. So, apart from the above, when should sheet metal be straightened? The answer is that although certain things have sheet metal parts that need to be repaired, such as vehicles, etc. There are various ways of straightening sheet metal, for example, using a straightener machine, with the aid of some tools, or even simply using a hammer.
Why Do We Straighten Sheet Metal?
In short, the sheet metal needs to be straightened while it is distorted. The following are three situations that can lead to distortion of sheet metal.
● Residual stresses
The most common distortion caused by residual stresses occurs during the rolling process. Rolling is a machining process which uses several rolls to flatten or form the sheet metal. It should generally finish perfectly, which will provide a fine sheet of metal for further use.
This is a common situation for a happy ending. However, sometimes mechanical adjustment errors occur, such as inconsistent distances between the rolls. Once this occurs, this inconsistency will seriously affect the levelness of the sheet metal. For example, if the distance between the two rolls is too narrow, the sheet metal will be stretched more, thus making some parts of the sheet metal thinner. On the other hand, if the two rolls are further apart, the sheet metal will not be able to withstand sufficient pressure to make it thicker. As a result, the machine-made sheet metal will be uneven and distorted, which is not allowed to be used in the manufacture of products.
● Deformation caused by the progress of steel processing
In addition to pressure, metal can be processed in many other ways, such as heating and cooling, shearing, cutting, welding, etc. In the previous section we learnt that inconsistent pressure can distort sheet metal. In the same concept, the processing methods listed above can damage sheet metal if they are applied unevenly. For example, temperature variations such as uneven heating or cooling can lead to uneven sheet metal forming.
● Improper transport or storage
Deformation can occur at any stage, sometimes during the production process, sometimes during transport and sometimes even in storage premises. The most common way of storing well-formed sheet metal or metal materials is to stack them on top of each other, which is recognized as the most space-efficient way of storing them, but may in fact cause some degree of damage due to pressure.