On the principle and application of anti channeling turning-roll

For the welding turning-roll,when both the roller and the weldment are ideal cylinders,and the size of each roller is the same, and the rotation axis is in the same level and parallel to the weldment axis,the weldment will rotate around its own axis without axial movement. 

However,when one of the conditions is damaged,such as the manufacturing and installation error of the welding turning-roll,the irregular geometry of the weldment, the height difference between the front and rear rollers,and the axis of the roller is not parallel to the axis of the weldment,resulting in the self weight of the weldment and the axial component force in the contact between the driving roller and driven roller and the weldment,the weldment will move in the axial direction.

The welding quality and welding process are carried out normally.Some manufacturers use the method of hard top at the end of the weldment to stop the movement of the weldment. This method will damage the weldment and equipment.Therefore,the development and application of the anti galloping turning-roll can control the movement momentum of the weldment within ±3mm,which can meet the requirements of various welding methods for welding position accuracy.

It has been proved that the parallelism between the axes of the roller and the axis of the weldment is the main factor affecting the axial movement of the weldment. Therefore, when manufacturing and using welding turning-roll, attention should be paid to: 

1) The center line of the driving roller carrier and the driven roller carrier shall be consistent; 

2) The roller spacing shall be equal; 

3) The axes of each roller shall be in a horizontal plane and parallel to each other.

Article 6.2 of JB/T9187-1999, revised by China in 2000, stipulates that the circumferential speed of the driving roller should be steplessly adjustable in the range of 6-60m/h,the speed fluctuation should be less than ± 5% or ±10% according to different welding process requirements,and the circumferential speed of the roller should be stable and uniform,and crawling phenomenon is not allowed.According to JB/T9187-1999 article 6.9:when the cylinder workpiece is welded on the anti axial movement roller carrier, the axial movement of the workpiece shall be less than ±3mm during the whole welding process.

In the actual production,in order to weld of different diameters,the distance between rollers of welding turning roller should be able to reduce joints.There are two ways of adjustment: one is self-regulation;the other is non self-regulation.The self-adjusting type can automatically adjust the spacing of the roller carrier according to the diameter of the weldment.There are three types of non self-adjusting ones:adjustable screw rod, manual bolt shifting and electric sliding plate shifting.By adjusting the center distance of the roller the cylinder with different diameters can be applied.On the basis of non self-adjusting roller carrier,the roller of driven frame is made into lifting type.Photoelectric encoder is used to detect the movement of workpiece,and the system controller controls the lifting of driven roller.The displacement detection frame is placed at one end of the workpiece,and the detection wheel is pressed on the end face of the workpiece (the end face must be processed).The detection wheel can rotate with the workpiece. 

When the workpiece moves axially,the detection wheel will move with the workpiece.The photoelectric encoder detects the movement and direction of the workpiece,and the signal is input to the system controller for processing.The controller can adjust the lifting stroke,speed and interval time of driven roller according to the amount of movement,and control the up or down according to the movement direction.The movement of workpiece always fluctuates between -2mm and +2mm.In this way,the movement of workpiece is limited in a certain range,which can basically meet the needs of welding.

With the development of science and technology,great progress has been made in the practicability and reliability of the anti channeling welding turning roller.Through the actual test,its comprehensive index is close to or better than that of foreign similar products, and is more and more used in production.