Summary:
uired
find HP of electrical Motors Required

Dear guys,
As you see in picture, there is a two rolls.

Top roll have a Rubber Surface Coating (Weight : 1000kg, OD:550mm, ID: 448mm, Face Length : 1950mm),
Bottom roll (Weight : 1500 kg, OD:605mm, ID: 535mm , Face Length : 1950mm ) is a steel surface.

Now the paper pass between them, and load applied to press the paper, (Nip Pressure) is 200 kg/m2.

And my question is, How can I calculate HP required to rotate the roll at 100 rpm.

NOTE: i even make the formula table (Attached Herewith) from the another post given in the https://www.physicsforums.com/showthread.php?t=201254, But the load consideration is not there..

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• Calender.jpg
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• HP Calculation.xls
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anorlunda
Staff Emeritus
The power needed depends on the rolling resistance, or friction. That is normally something that we measure by experiment, not calculate. Formulas are not helpful if we do not know the values of the coefficients.

If you don't have access to a test machine, or to a laboratory, I suggest looking at similar rolling mills and find out what size motors they user.

If you really want a calculation (and I cannot tell you how to do such), you will have to get into the deformation mechanics of the rubber roll face. Rubber is a somewhat strange material, rather nonlinear. As Anorlunda has said, an experiment is probably your best option.

jrmichler
Mentor
Ah yes, a rubber on steel calendar. I've seen many of them. As @anorlunda and @Dr.D posted above, there are no equations. You need to run some tests, or scale from existing machines. Keep in mind that the rolling resistance is due to hysteresis in the rubber, so is dependent on the exact rubber formulation, nip pressure, and running speed.

Asymptotic and phinds