About Straightening in punch and shaping technology
Principle of roller straightening
1. Metal sheets up to more than 50 mm in thickness and metal strips down to the thinnest sheets are straightened in straightening machines before further processing. 2.  The sheets are subjected to a process of bending back and forth between rollers arranged as shown above with decreasing curvature.  3. The number of straightening rollers depends on the required straightening result. 4. Hardest to straighten are sheets that have unevenness not only in the rolling direction, but also transverse to it. In this case at least one precision straightening machine is required and the straightening process may need to be repeated several times to eliminate the multiaxial tension states in the sheet. 5. The best straightening results are achieved on a precision straightening machine designed with extremely limited stretching and equipped with roller deflection.
Straightening machine drive
1. All rollers are driven together by the distributor gear 2. Drive via three-phase motor, which has a frequency inverter as standard equipment. Depending on the application, a servo drive may also be used. 3. Strip straightening machines are constructed with a run-through speed of up to 120m/min for strip supply operation for pressing. 4. Part straightening machines are designed for a maximum of 20 m/min
How can i achieve good straightening result
1. Good initial material 2. The smallest possible straightening roller diameter+ roller distance 3.  Straightening machine with low strain and bending 4. At least 9 straightening rollers to straight coil curvature  5. At least 15 rollers for flat straightening, optimally 19/21 pieces  6. Straightening rollers must be supported