It minimizes machine vibration, noise, web flutter, and bearing wear. It also minimizes the effect of critical speed.
If the roll is very short in relation to its diameter or if the running speed is very slow (below 100 rpm).
In practice, the perfect balancing cannot be achieved because some inherent unbalance will remain. The best one can do is to reduce this unbalance to a certain acceptable level.
It can be either. Most of the time, Double E Group adds weight to the roll.
When weight is removed, it is removed from the end of the roll by drilling holes in the end.
When weight is added, it is added on the inside of the tube near the ends. Weight is added to the middle of the roll if it is "whip" balanced.
The materials used are lead and a two-part epoxy called Dynaweight.
It is an ISO 1940-1 Balance Quality Grade. The numerical value of "G" is equal to the vibration velocity mm/sec (6.3 mm/sec = .25 in/sec) of a freely suspended rotor.
The ISO 1940-1 recommends paper machinery rolls and print rolls to be balanced at this grade.
5500 FPM
Yes, the charge is figured on a case-by-case basis. The charge is related to the extra time required to perform this balance.
Typical balancing machines made to handle long rolls (+140" long) are made to balance to a certain sensitivity based on the customary weight of a metal roll of that size. Composite rolls present a special set of conditions which require higher sensitivity than most industrial roll balancing machines are able to handle due to their light weight. Double E Group has balancing machines to handle a full range of idler rolls sizes, lengths, and weights.
SealMaster ERX bearings have 10%-15% of the grease a standard bearing would have. Standard bearings have a 40%-60% grease fill.
Andok B grease
180 to 200 degrees Fahrenheit