Fanuc AC Servo Motor A06B-0235-B400 A06B0235B400 AO6B-O235-B4OO

Part Number: A06B-0235-B400
Also Searched As: A06B0235B400, Fanuc A06B-0235-B400, FANUC A06B0235B400
Motor Model: αiS 8/4000
Classification: Fanuc Alpha iS Series AC Brushless Servo Motor

The αiS 8/4000 is one of Fanuc's most widely deployed machine tool servo motors. The A06B-0235-B400 configuration features a straight smooth shaft with 24V spring-applied brake - ideal for vertical CNC axes requiring flexible disc or split-hub couplings and functional safety braking.

• 8 Nm Stall Torque at 4,000 rpm rated speed
• 2.5 kW Rated Output for demanding CNC applications
• Straight Smooth Shaft (ST, SLK) for precision servo couplings
• 24V Spring-Applied Brake for vertical axis safety
• Alpha i A1000 Absolute Encoder with 1,000,000 pulses/revolution
• IP65 Protection Rating for industrial environments

Eight Newton-metres of stall torque provides substantial capability for high-demand machining cycles. On a 10mm pitch ball screw with 90% efficiency, 8 Nm sustains approximately 4.5 kN of axial force - sufficient for vertical Z-axis applications with meaningful margin for cutting loads.

The 4,000 rpm rated speed drives a 10mm pitch screw at 40 m/min in direct coupling, achieving practical rapid traverse speeds without requiring gearboxes. The 2.5 kW continuous rated output handles typical CNC machining duty cycles without thermal overload.

The straight smooth shaft (ST/SLK designation) interfaces with split-hub precision servo couplings including bellows, disc, and jaw couplings that transmit torque through friction clamping. This design simplifies motor replacement - simply loosen the coupling clamp, slide the hub off, and reinstall without keyway alignment or taper seating procedures.

The electromagnetic brake is spring-applied and electrically released, providing fail-safe operation for vertical axis applications:

• Spring holds brake engaged by default
• 24V DC required to release brake for rotation
• Automatic engagement during E-stop, power loss, or servo-off
• No software or electronic dependencies for safety function
• Essential for vertical Z-axis spindle head retention

The serial absolute encoder provides 1,000,000 pulses per revolution resolution, enabling sub-micron positioning capability. Combined with the spring-applied brake, this allows immediate position recovery after power events without homing cycles. The multi-turn absolute counter is maintained by backup battery in the servo amplifier.

• Vertical Z-axis on CNC vertical machining centers with flexible couplings
• CNC turning center vertical or inclined feed axes
• Automated cell vertical transfer and lift axes
• Z-axis on Fanuc robot work positioners and tilt tables
• Replacement for worn B400 units on existing machines