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Controlling the movement of the axial stand in the ring mill

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Two steps to control the movement of the axial stand in the ring mill We know what the axial stand is and how it moves( Movement of the axial stand in the ring mill ).  As we know, the axial stand moves backward as the ring grows.  And now I’ll explain how the ring rolling machine developers like me control the axial stand’s movement.  You may not be a ring rolling machine develper, but it could be helpful to troubleshoot the problems with axial stand’s movement if you understand how it works and is being controlled. When the vertex of the axial roll coincides with the center of the ring, there’s no slip between the ring and the roll(main roll or axial roll).   So we control the position of the axial stand to be coincided with the center of the ring.  But when the ring grows and reaches the maximun range of the axial roll, we cannot make the vertex of the axial roll be coincided with the center of the ring.  We need to change the way we control the sta...

Movement of the Axial Stand in the ring mill.

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What is axial stand? The axial stand supports the axial roll assembly and moves the axial roll assembly as the ring grows.   There are axial rolls, axial roll gear box, axial roll motor and TR in the axial stand. Movement of the axial stand The axial stand is moved by the hydraulic cylinder in the direction of the long axis of the ring mill. I explained in my previous post( Do you know why the axial roll is cone shape? ) that the linear velocity distribution by the main roll and the linear velocity distribution by the axial roll correspond when the virtual vertex of the axial roll(C a ) coincides with the center of the ring(C r ). The ring mill program controls the position of the axial stand so that the virtual vertex of the axial roll matches the center of the ring. As the ring rolling progresses, the ring becomes larger. As the size of the ring increases, the center of the ring moves away from the main roll. As the center of the ring moves, the axial stand ...

Controlling the roation speed of main roll

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I explained that the rotation speed of the main roll is constant in the ring rolling machine( Rotation speed control of axial roll ). But it isn’t constant in the CALTEK ring mill. I’ll tell you why the rotation speed of the main motor is not constant in our ring mill. Increasing the rotation speed of the roll during rolling can reduce the rolling force because the coefficient of friction between the roll and the workpiece becomes smaller.  That’s why I always ask the ring mill operators to make the rotation speed of the main roll as fast as possible.  However, if the size of the ring is small, the ringmill operator should not rotate the main motor in the maximum speed. I’ll explain the reason with this ring mill belows: * Main motor rpm : 0 ~1,200 * Main roll gear box reducer ratio : 1/40 * Axial roll cone angle : 40 * Axial roll gear box reducer ratio : 1/10 * Axial motor rpm : 0~1,400 * TR range : 200~600 Tis is a graph of the rotational speed of the axial motor according t...

Rotation speed control of axial roll.

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The driving force that rotates the ring in the ring mill is generated by the main roll and the axial roll. Of these two rotational speeds, the rotational speed of the main roll is used as a reference, and the axial roll is controlled according to the rotational speed of the main roll.  Normally, the rotation speed of the main roll is fixed and the rotation speed of the axial roll is controlled according to the position of the ring. In the previous, we have understood the concept of linear velocity( What is linear velocity ) and studied how to obtain the linear velocity of the main roll( The linear velocity of main roll ) and the linear velocity of the axial roll( The linear velocity of axial roll ). The linear velocity of the main roll(V m ) is fixed and constant and we control the rpm of axial roll to match the linear velocity of the axial roll(V a ) with that of the main roll. The linear velocity of the main roll(V m ) is, V m = R m x ω m The linear velocity of the a...

The linear velocity of the axial roll in ring rolling.

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I posted on this blog about the linear velocity of the main roll.( The linear velocity of the main roll in ring rolling ) The formula for calculating the linear velocity of an axial roll is a bit more complicated than that of the main roll because the axial roll is a cone shape. As you know, the linear velocity is the product of the rotation radius and the rotation speed. V = R x ω (V : linear velocity, R : rotation radius, ω : rotation speed) 1. The rotation radius of the axial roll The rotation radius of the main roll(R m ) is constant, but the rotation radius of the axial roll(R a ) varies with the position of the ring. The rotation radius of the axial roll(R a ) is, R a   = TR x sin(θ/2) (TR : the encoder value of the Tracer Roll, θ : the cone angle of the axial roll) I explained in the previous post about the TR encoder( The encoders of the ring mill ). 2. The linear velocity of the axial roll The linear velocity of the axial roll is, V a = R...

The linear velocity of main roll in ring rolling

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The linear velocity is proportional to the rotation radius and rotation speed.The linear speed of the main roll is obtained by multiplying the radius of the main roll by the rotational speed of the main roll. V=r × ω There are a motor, gear box and main roll in the main roll assembly. The main roll assembly has a main motor, gear box and main roll. In general, the main speed displayed on the ring-mill program screen is the rotation speed of the main motor.  The main roll assembly has a main motor, gear box and main roll. In general, the main speed displayed on the ring-mill program screen is the rotation speed of the main motor. The rotation speed of the main roll( ω M ) is calculated by the rotation speed of the motor( ω m ) and the reduction ratio of the gearbox(R). ω M = ω m ×R Therefore, the linear velocity of the main roll(V) is, V=R x  ω M  ( R : reduction ratio of the main gear box,   ω M  : rotation speed of the main motor) L...

What is the linear velocity?

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There are usually three ways to express the speed of rotation. They are rpm , angular velocity and linear velocity .   rpm is the number of revolutions per unit time. The unit of rpm is rev/min.   Many people confuse linear velocity with angular velocity.  I will explain the difference between linear velocity and angular velocity, and how to calculate linear velocity. Angular velocity is the angle of rotation per unit time.  The unit of angular velocity is rad/s.  Linear velocity is the distance traveled per unit time.  The unit of linear velocity is m/s. The formula of angular velocity( ω)  is belows: ω= θ/t ( θ : angle, t : time) Linear velocity is the distance of the arc that moves per unit time. The length of the arc is as follows: ℓ=r θ The linear velocity( V)  is as follows: V= ℓ/t= r θ/t=r ω Linear velocity(V) is proportional to rotation radius(r) and angular velocity( ω). ...