rolling 1

[sahinoz]

hi everyone,
Let say, I have a 75mm diameter clay cylinder and I want to reduce its diameter to 50mm by using bunch of rollers. I know that I can reduce its diameter by using only one roller couple but I just want to know what kind of calculations I have to go through in order to decide the number of rollers if I work with real metals like Al, or steel.

thanks in advance

 

[ccw]

Hi Sahinoz,
It is not clear what process you are describing. Are you going to "extrude" or "draw" through rollers by moving the round along its axial direction, and is it continuous or can the round be fixed length, or are you going to compress an initial fixed length of round in the center of an array of parallel cylindrical rollers? Are you going to do this hot at 50 to 75% of melt temperature or are you going to do it cold? Do you need any particular physical properties or dimensional control in the material after it is finished? Does this process need to have availability and maintainability considerations for a long duration process or is this laboratory "one shot" work?

 

[sahinoz]

Hi ccw,
thanks for the reply. Actually I want to design a small device which I will draw playdough through horizontal roller couples to get a perfect cylindrical shape. it's obvious that I can do it in one shot by using only a roller couple but instead of using only one couple I want to use several, (may be 3) because the device is going to be used in manufacturing labs to demonstrate the rolling operation to students. so, it's going to be simple. But i still need to come up with some mathematical proofs that show the reasons behind my dimensions of rollers, HP or torque of my motor, etc. If I can figure out the calculation process for this device, I can easily built something real, right.

thanks

 

[ccw]

Hi Sahinoz,
While I applaud your effort to demonstrate metal forming principles, I disagree with your one couple approach to get a perfect cylinder shape. If one examines the tangential velocity at several material contact points of the couple of rollers, one will see that the part will have considerable distortion using this approach.

Also, in the real world of rolling metal rounds, your approach will result in very high axle bearing loads. There are geometric problems getting large enough roller axle bearings close in to the rolled part. In the real world the rolls would be backed up by other rolls (stacked) so additional bearings could be brought into play.

I don't know of any metal rounds formed the way you describe, but that is not to say there are none in existence.

Also, play-dough is a plastic, almost from the start. It probably has some definable, repeatable realastic properties but no where near metallurgical properties. I think you should consider whether play-dough is scalable to metal mechanical properties before proceeding.