A nip set consisting of two nip rollers is widely used on web lines to adjust web line tension, feed in inks for printing, conduct lamination, and etc. The nip rollers may have cover material such as rubber or foam. Here we are curious how the velocities and tension are changed by the different configuration of nip set. Specifically, we studied two types of the problem: the type-1 problem has the tension control on both upstream and downstream ends of the nip couple; the type-2 problem has the velocity controlled upstream and tension controlled downstream.

Two types of problems

We developed an implicit dynamic Abaqus model and studied the problem of a web transiting through a nip roller set. We studied different nip couple configurations: rubber-covered nip roller against rigid roller and rubber-covered nip roller against rubber-covered nip roller. We investigated how the nip loads and rubber material properties affect the tension and velocity upstream and downstream of a nip set for two types of problems with two nip configurations. This study provides additional detailed information for classic tension control theory with nip couples. The contact status (slipping / sticking) developed between nip rollers and the web has insights to the more accurate control in printing and lithography applications.

The maximum principle stress developed in nip-cover

The contact status: slipping / sticking between nip rollers and web