This video shows a motor shaft being straightened automatically after machining and heat treatment. The slender stepped shaft is supported between centers or on V-rests, a measuring head scans runout at the bearing seats and rotor fits, and the press corrects each bend before the shaft moves on to rotor stacking — a sequence built for the fast cycles motor manufacturers demand. Straight, balanced rotor shafts run quieter and extend bearing life, which is why motor makers straighten before rather than after final assembly.
Motor shafts run at high RPM, so residual bend must be minimal: the closed-loop system holds automotive-grade TIR of 0.02–0.05 mm and reaches precision grades of 0.02 mm or better where bearings require it, with springback compensation on hardened shafts, at 20–90 seconds per shaft. Measurement principles are covered in our article on TIR runout measurement.
The platform covers industrial motor shafts, servo and EV traction-motor shafts and generator rotors across a wide diameter span — a single machine commonly covers Ø20–120 mm with changeover by program, and one operator can run one or two CNC machines. See the automatic machine range for standard configurations.
To discuss your application, contact the SHANGDA engineering team with drawings and annual volume — factory visits in Tengzhou, Shandong are always welcome.
Straightens motor, servo and EV traction-motor shafts
Measures at bearing seats and rotor-fit diameters
TIR 0.02–0.05 mm; ≤0.02 mm precision grade for high-RPM shafts
20–90 second cycles for high-volume motor production
One machine commonly covers Ø20–120 mm by program changeover
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