Straightening machine are heavy machinery mostly employed in metal working industries. They are used to straighten different types of steel and metal objects like wires, bars, rods, sheets, beams, angles, channels, flats, H-beams etc. These machines are mainly designed to eliminate size inadequacies caused due to improper control means and procedures in steel rolling, cooling, impact and extrusion as well as other factors that might cause it to become bent and distorted during handling or transportation. These machines are also used to eliminate wavy edges, camber, centre buckles and trapped stresses within the material. Moreover, these machines help to remove up and down bending, side bending, torsion, gnawing, correction cracks, rolled on markings and other defects in the product.
These machines are divided into two categories: roll-type and stretching machines. The former type of machine is generally distinguished by the use of large diameter closely spaced work rollers that are usually backed up with small support journals. This arrangement is also known as a straightener or flattening machine and is the more common straightening solution.
A more advanced version of the straightener is known as a precision leveller. Unlike straighteners, which are typically built to handle the full range of metal thicknesses and widths, levellers can be specified with a specific range of maximum work-roller depth settings. This depth setting, often referred to as the ‘zero’ or ‘home’ position of the work-roller depth is the point at which the first upper work-roller reaches the surface of the material with no daylight between it and the corresponding lower fixed-roller.
If the work-roller depth of the machine is set at this location, the entire width of the sheet of metal can be run through the machine without excessive deflection of the work-rollers. Deflection of the work-rollers can result in a loss of contact between them and the sheet of material, reduced straightening efficiency and, in the worst case, broken work-rollers.
In order to determine the maximum work-roller depth setting for a specific machine, the manufacturer will provide the user with guidelines that are applicable to that particular model of straightening machine. The guidelines will typically be based on the maximum width of the machine and the maximum possible material thickness.
One of the most important parameters when determining the appropriate power supply for a straightening machine is the maximum yield strength of the material. This is because materials with higher yield strengths will require more power to be straightened than those with lower yield strengths.
A final note about the power requirements for straightening machines is that the amount of work-roller diameter and center distance spacing will have a significant impact on the overall power required to process the material. Consequently, the more precise the specification of the machine is in this regard, the more accurate the power requirement will be. This is especially important when attempting to match the capabilities of a straightener with the characteristics of specific material types.