A basic principle of the roll forming process is that the strip is bent in a straight line longitudinally. However, the pressure generated during bending deformation combined with the residual stress present in the strip often causes the strip to deviate from the cold bending equipment.
To describe the degree of deviation of the strip from the subsequent forming roll, the commonly used words are: side bending-horizontal bending, warping-vertical bending, twist-spiral. A straightening mechanism should be used at the end of the roll forming machine to solve these problems.
The basic principle of the straightening mechanism is to apply sufficient pressure in the opposite direction through the correcting mechanism to deform the profiles with side bending, warping and other defects. If the amount of deformation in the opposite direction is appropriate, the profile can be completely straightened after springback.
If the profile is twisted in one direction and the straightening mechanism sequence rotates the profile in the opposite direction, plastic deformation will come up. If the angle of rotation is suitable, the profile will no longer twist after springback.
Straightening of bends or twists is usually carried out between the last forming roll and the cut-off die of the roll forming machine. If the last roll does not support the profile effectively, the entire profile section must be supported when entering the side of the straightening mechanism. When straightening an asymmetrical profile, there is a possibility of torsional deformation at the same time as straightening. At this time, it is necessary to perform bending and torsional straightening simultaneously in the opposite direction of profile deformation.
During the straightening process, the profile will move up and down, left and right, so the gap between the straightening mechanism and the profile is required to be relatively loose. There can be a certain gap between the straightening mechanism and the surface of the profile.
The commonly used straightening mechanism is the Turkish correction head.
Roll forming machines are widely used in metal manufacturing, mainly for metal forming. The connection form of the roll forming machine can generally be divided into two types: detachable connection and non-detachable connection:
1. Common non-detachable connections include welding, riveting and interference connections and so on, among which interference connections are mostly used for shaft and hole matching. To achieve interference connection, methods such as press fit, thermal expansion fit and cold shrink fit are commonly used.
The general spring machine can use the press fit method and the important or precise machine can use the thermal expansion and cold shrink fit method.
2. Removable connection of interconnected parts does not damage any parts and can be reconnected after disassembly. Common detachable connections include threaded connections, key connections and pin connections. Among them, threaded connections are widely used.
The quality of the threaded connection of the roll forming machine has a lot to do with the assembly process. The tightening force of each bolt, the tightening sequence of multiple bolts and the balance of tightening force should be reasonably determined according to the shape of the connected parts and components of the computer spring machine, the distribution and force of the bolts.