Straightening machine is a heavy metal working equipment mainly used in industries to straighten different type so metal objects like bars, rods, strips, wire rod, studs, metal scrap, plates, channels, H-beams, tubes, and metal pipes. These machines are specially designed to achieve optimum straightening quality of various metal products. They are also used to eliminate residual stress, up and down bending, side bending, and torsion of rolled or drawn metal products, which can cause many other flaws in the end product such as gnawing, correction cracks, and incorrect marking.
Straightened metal products can be used for a variety of purposes such as manufacturing, engineering, and construction. In addition to the benefits of higher straightness, the use of a straightening machine can reduce the overall cost of the product and improve its appearance. In order to maximize the efficiency of the straightening process, it is essential that all variables associated with the machine are defined. This includes the optimum work roller depth setting, maximum straightening force, and minimum deformation. These factors are used to design the optimum straightening system for each application.
A typical straightening machine consists of a fixed set of deflectors and a moving head, both of which are powered by a drive motor. There are several methods of driving the work rolls, including discrete drives for each roller or a combination of power and speed limiting devices for each pair of deflectors. The number of working rollers can vary from two to ten, depending on the material thickness and width.
Generally speaking, the work roller depth setting is calibrated for the initial run of each material. Once the optimum depth is established for a particular material, it must be consistently returned to this point each time the machine is operated. This is critical in ensuring the work rollers produce the desired level of flatness and do not deform the product. Most straighteners utilize a simple calibration scale and pointer to establish the roller position.
For very long or thick products, the use of back-up rollers can provide additional support and reduce the pressure applied to the work rollers. The back-up rollers can be positioned in one, two, or three locations along the width of the work roll. The proper positioning of these rollers minimizes stress and potential deflection in the work roll, thereby increasing its life.
The Danieli multi-roll straightening machines offer high speed and excellent final bar/profile straightness. They are capable of handling large bending moments, allowing operators to apply a greater bending moment at the first pair of deflecting rolls and lessen it with each successive pass. This results in lower straightness tolerances and a more consistent finish. It also reduces the amount of re-straightening required after annealing. Consequently, these machines have a significantly lower operational cost per ton than other types of straighteners. Danieli has been designing and producing these types of machines for over 50 years. The machines are available in a wide range of sizes to handle bar diameters from 4 mm up to 250 mm.