Calculating the pressure force of a lever roller printing press

[Eubie]

Hello Everyone. I need some advice in calculating the pressure of a roller printing machine. The machine is operated by a geared rotating lever which moves the impression roller across a print surface. I had thought it was a case of using the equation for rolling friction to work out the normal force and then just to use the normal force in the pressure formula but its not making sense to my mind. The way I have been doing it is by calculating the torque on the roller axle to work out a tangential force acting on the roller which I have been assuming is equal to the rolling resistance force, then using a coefficient of rolling friction to get the normal force from the roller onto the surface but I am sure something is not right. I know the deformation of the roller is important but again I was not sure exactly how it comes into play. I am assuming the roller is made of ebonite rubber with a young's modulus of 500MPa and an input force on the handle of 100N. I also assumed an area of 5mmx127mm because the 127mm is the roller length and I just used the 5mm to give something to work with, I realize that's not correct but I just did it to get an estimated pressure area. Here is how i saw it.


F_n(normal force)=F_r(friction force)⁄CRF(coefficient of friction)

F_n=100⁄0.01

F_n=10000N


P=F_n⁄Area

P=10000⁄0.00127

P=7.8 MN⁄m^2

I have attached a couple of sketches of the problem. Ignore the 200mm length as I changed it afterwards to 127mm. Any help with this would be much appreciated. Cheers.

 

[gtoguy97]

To calculate the pressure of a roller printing machine, you will need to take into account the size and shape of the roller, the force applied to the roller, the coefficient of friction between the roller and the surface, and the elastic properties of the roller. First, calculate the normal force on the roller by multiplying the applied force by the coefficient of friction. Then, use the normal force to calculate the pressure on the surface using the equation P = F/A, where F is the normal force and A is the area of the roller in contact with the surface. Finally, take into account the elastic properties of the roller by calculating the deformation of the roller due to the normal force. This will give you an estimate of the actual pressure on the surface.