Rotogran rotors are a welded and machined fabrication. This method produces a higher quality rotor in terms of material specification and long term durability.
The rotor is welded fabrication made from a 5” diameter C1045 HRS and several flame-cut profiles cut from C1045 plate comprising the rotor fins. The rotor shaft and fins are pre-machined for assembly and fitted together in an accurate positioning jig. The tack-welded fabrication is then pre-heated in a rotating heat soaking furnace after which final semi automatic welding is done while the shaft is still in the furnace. After cooling, the fabricated rotor is sent for stress relieving and then on to the machine shop.
The rotor is turned on a lathe to bring the journals and fins to size, and then machined on a CNC boring mill to finish the blade seats and tap the blade mounting holes. Finally, the rotor journals are precision ground to accept the bearings and the flywheel bushings.
Following machining, the rotor is dynamically balanced and inspected before assembly into the granulator chamber.