The Flying Shears of Steel Rolling MillAuthor : hani Time : 2021/09/10
1. Basic Requirements for Flying Shears
The cutting edge is synchronized with the rolling piece in the direction of the rolling piece’s movement: V=(1-1.03) Vo, Vo is the rolling piece speed, and at the same time completes the cutting to length, meeting the precision requirements of length and shape, and the productivity of the rolling mill or unit requirement.
2. Adjustment of Cutting Length
1) Adjust the Length of the Flying Shear of the Starting Working System
The shear length L is determined by the photoelectric device (or hot metal detector): l = VOT ± L ‘, where l’ is the distance from the photoelectric device to the flying shears, VO is the forward speed of the rolled piece, and t is the delay time of the flying shear. When the photoelectric device is in front of the flying shear, it takes a negative sign, and when it is behind, it takes a positive sign.
2) The length of the flying Shear of the Continuous Working System
When the rolling speed Vo is too large or the cutting length is too long, the flying shear of the starting working system cannot meet the requirements. The flying shears of the continuous working system must be used. The drive can be driven by a motor, or can be driven separately, changing the spindle speed n and changing the air cut coefficient k can change the fixed-length length L of the rolling piece.
3. Uniform Speed Mechanism
The cut-to-length length L of the rolled piece can be adjusted by adjusting the rotation number n of the main shaft of the flying shear, but at the same time, the horizontal speed v of the cutting blade must be kept equal to the speed Vo of the rolled piece during cutting, which is the so-called speed Synchronization, the mechanism that realizes this function is called a uniform speed mechanism, which is generally divided into flying shear spindle for unequal speed motion, and flying shear spindle for constant speed motion.
4. The Main Shaft of the Flying Shear Moves at Unequal Speeds
Including double crank uniform speed mechanism, elliptical gear uniform speed mechanism.
5. Uniform Speed Mechanism of Flying Shear Main Shaft for Constant Speed Motion
The flying shear with unequal speed of the main shaft has a relatively large eccentric mass, so the dynamic torque is large, especially when the speed is high, so it is generally used in high-speed shearing. In order to change the fixed length, the spindle speed n of the flying shear must be changed. In order to maintain the synchronization performance, the method of changing the radius of gyration of the knife-edge is adopted to achieve the goal of uniform speed, that is, the increase of n reduces the fixed length and reduces the radius of gyration R at the same time. To maintain the horizontal speed of the cutting blade equal to Vo.
6. Types of flying shears
Double drum flying shears, rotary flying shears, crank flying shears.