Profile Ring Rolling

The three main rolls in the ring mill are the main roll, the mandrel and the axial roll. This means that these three rolls wear quickly and that these rolls should be replaced frequently. And among these three rolls, axial roll is the most expensive roll. Because the axial roll is cone shape, it is difficult to machine.   Why is the axial roll not a cylindrical shape that is easy to machine, but a cone shape that is difficult to machine? I have to explain the linear velocity of the axial roll to tell the reason. I explained the linear velocity of the main roll before  YouTube(What is the linear velocity) In the ring mill, the main roll and axial roll rotate the ring.  The linear velocities of the ring by the main roll(V1) and by the axial roll(V2) should be same.  This ensures that the ring remains in the center of the ring mill. When the linear velocity(V2) of the axial roll is faster or slower than the linear velocity(V1) of the main roll, the center of the ...

1. Cause of the ring climbing There are some reasons for the ring’s climbing up and down(Rippling). In this case the bad shape of the preform is the main cause of the ring’s rippling. I explained the process of making preform at my blog before. The process of making preform is cogging→upsetting →p unching →p iercing as I explained at that post. When you press the punch too much and don’t make the preform flat, you will have this bad shape of preform. When the axial roll press down the preform, the other side of the preform will go up. It’s not easy to make the ring stable if this happened. 2. Result of the ring climbing You can see a gap between the stacked rings. And you need to add more excess material for the ring. It makes the ring expensive 3. How to solve this problem If you have to press the punch deeply to save the material, you have to make the preform flat after piercing it. The quality of the preform is very important. It aff...

I got a call from the ring mill operator of my company. He told me that the main roll stopped rotating while rolling a ring. But the main roll was rotating when I arrived at the ring mill shop. I wasn’t at the sight so I couldn’t see the problem.  I looked over the technical data saved in the PC. And I could find the cause of this problem as soon as I saw the data. * Technical data of CALTEK ring mill I found the main motor was rotating at high speed and the motor current went down suddenly. If the motor is over current, it could be stopped. But the current is not high in this case. I could guess the motor had no problem, it was normal. But why didn’t the main roll rotate? There’s a gear box between main motor and main roll. It transfer the motor’s driving power to the main roll. Motor rotates but main roll doesn’t rotate.   I can guess there’s something wrong in the gear box. We checked the gear ...

There are 3 kinds of dimension to design the ring rolling product. They are machining, cold and hot ring dimensions. The first step to design the dimension of ring rolling products is analyze the customer drawings. There may be some different ODs, IDs and Hs in the drawing for the customer products. Among the many ODs, IDs and Hs, the maximun OD , minimun ID and maximun H come to the dimension of machining ring. The machining ring dimension of this item should be   OD 1,500 * ID 980 * H 150 . You need to design the dimension of the cold ring by considering the additional dimension. You decide the hot ring dimension by considering shrinkage from the hot ring to the cold ring. You can use this expression to calculate the hot dimension: Hot dimension = cold dimension ×100÷(100- shrinkage rate) The shrinkage rate can be different depending on the ring dimension, material, the atmosphere temperature of the factor...

The process for manufacturing ring rolling products is as follows: Cutting →  Heating →  Blanking →  Ring Rolling →  Heat treatment →  Machining The blanking and ring rolling processes are main forging processes among these processes. I’ve introduced the ring rolling process before, I’ll introduce the blanking process this time. Blanking is the process of making a preform for ring rolling. Blanking processes are 1. cogging, 2. upsetting, 3. punching and 4. piercing. The cogging process is a process to make a square material into a circle, and it is not necessary if you use a round bar as a raw material.  The upsetting process is the process of compressing the material in the longitudinal direction.  The punching process is the process of inserting a punch to make holes in the material.  A piercing process is a process of punching holes in a material.  This is the finished prefor...

There are a total of 6 encoders in the ring mill, and the dimensions of the ring are measured using these 6 encoders. In order to determine the shape of the ring, three dimensions of outer diameter, inner diameter and height must be measured. The outer diameter of the ring is the sum of two encoders: Axial Slide Encoder and TR Encoder. To measure the inner diameter of the ring, the values of three encoders, an axial slide, a TR, and a mandrel encoder are required. The inner diameter of the ring is calculated by the Axial Slide Encoder + TR Encoder -2 × Mandrel Encoder. The height of the ring is the value of the Axial Roll encoder. If you have measured the dimensions of the ring immediately after you produce the ring and the actual measured ring outer diameter differs from the the encoder value, you need to check the Axial Slide Encoder or TR Encoder. If the actual measured ID of the ring differs from the encoder value, you should check all three encoders: Ax...

The ring mill has six encoders to measure the ring dimensions. The mandrel encoder is the distance from the main roll to mandrel bar. The mandrel encoder is the value of the ring's radial thickness. The Axial roll encoder represents the distance from the lower axial roll to the upper axial roll. The axial roll encoder is the the height of the ring. The centering encoder is the length of the centering cylinder. The centering cylinder operates in a straight line, but the centering roll moves in a circular orbit based on the fixed point. As the centering cylinder stroke increases, the centering roll closes in the direction of the main roll and away from the main roll as the length of the centering cylinder decreases. There are two centering cylinders on each side of the main roll, and each centering cylinder has an encoder. The TR encoder is the distance from the virtual vertex of the axial roll to the tracer roll. The axial slide(axial stand) encoder i...