Back-up rollers for heavy duty levellers
BACK UP ROLLERS FOR LEVELER AND STRAIGHTENER 
Download complete catalog
Basically the different kind of back up rollers for metal flattening and straightening machines can be identified as:
1) Back up rollers of “NNTR” form (or similar to) without pin.
2) Back up rollers with cylindrical outer profiling with pin.
This publication highlights typical features and application data proper to back up rollers:
Maximum permissible dynamic and static load carrying capacity
The maximum permissible load carrying capacity on the roller (dynamic and static Frzull) must be taken into account when engineering a new project. Only using the load carrying capacity values and defined by ISO 281 and ISO 76 can be misleading.
It is important instead to review the inside dimensional proportioning, calculating dynamic Cw and static Cow values so to take into account the limiting elastic stresses when full load is applied to the back up roller.
Permissible maximum speed
The indicated maximum speed refers to back up rollers of full complement internal design, grease lubricated, and under a radial load calculated to achieve 50.000 hrs of theoretical L10h life.
Geometrical and dimensional tolerances
With often the need for higher than normal geometrical and dimensional tolerances, it is possible to furnish back up rollers in P6 and P5 precision classes and (if required) to supply them in factory preselected “H” section height classes for ease of assembly on the same shaft.
Radial internal clearance
Due to a usually high thermal temperature dispersion and the lack of press fit between shaft and bearing bore, the “normal” class of radial internal clearance as defined by DIN 620 is applied.
Axial back up roller guiding
When required by the application, it is possible to furnish back up rollers having inside a pair of roller or ball based thrust bearings, so to contrast axial loads.
Outside surface hardness
When required, it is possible to furnish back up rollers with a reduced outside surface hardness, so not to damage the intermediate and/or working rolls thus avoiding scratches and wear (we suggest at least a 2-3 HRC points difference).
Outside surface profiling
The outside surface profiling of back up rollers is cylindrical with both ends that can be either relieved or crowned.
This back up roller technical and engineering approach allows a variety of manufacturing solutions with regards to internal bearing design, lubrication and sealing system.
Whether a full complement, or with needle cages, to multirow cylindrical roller with cage and with ball or roller thrust bearing, several options are available to suit and solve specific application problem.
A standardized catalogue therefore becomes limiting to the many and different market requirements: for this reason Faro S.p.A. is at complete customer disposal to proactively study, engineer and execute optimized back up roller solutions.
The enclosed tables and listing show back up rollers and their technical data which have been actually engineered and manufactured by FARO S.p.A.
