4-roll plate bending technology offer many decisive advantages. Easy to operate, immediate plate alignment into the rolls of the machine, pinch pre-bending of the leading edge with load pre-setting.
Plate clamped into the central rolls to ensure safe bending without slippage; rolling the whole plate surface along with the trailing edge in one direction and in one pass. This makes the four roll machine the best technology for automated production via CNC controller and PLC sequence roll bending
source: http://www.mgsrl.com/