Each process is meticulous under strictly full test analysis to ensure every parts in stictly quality control standard.
All spindles  are in stringent quality control procedures to ensures every  spindle passes the all key points of specification to meet standard requirement , and meet special requirement from customer.
Air flow
Water flow
End float/lift off
Axial load (inner)
Axial load (outer)
Torque
Static RUNOUT
Dynamic RUNOUT
Motor check
Vibration
......