Siemens SIMOTICS M 1FE built-in synchronous spindle motor (also named 1FE1 frameless synchronous servo motor) is a frameless split-type direct-drive motor specially designed for CNC machine tool spindle assembly, perfectly matched with SINAMICS S120 servo drive system. Different from conventional flange-mounted servo motors like 1FK7 or 1FT7, this series has no complete motor housing and is embedded directly into the spindle housing by machine manufacturers to form an integrated high-performance motor spindle. Widely adopted in high-speed milling, precision grinding, multi-task turning center C-axis positioning and aerospace mold machining worldwide, it has gradually become the mainstream replacement solution for outdated 1PH series spindle motors.
1. Main Internal Structure of 1FE Built-in Synchronous Spindle Motor
The 1FE synchronous built-in motor consists of two core separated components: stator assembly and permanent magnet rotor, without end cover or standard casing.
- Water-cooled stator assembly
The stator core is wrapped with high-insulation class winding and integrated with an annular water jacket for circulating water cooling. The built-in cooling channel ensures continuous S1 rated operation under high-load and high-speed working conditions. Temperature sensors (PTC/KTY) are pre-installed inside the stator winding for real-time winding temperature monitoring and overheat protection.
- Permanent magnet hollow rotor
Adopts high-performance rare-earth permanent magnet embedded structure. Large central hollow bore allows spindle drawbar to pass through, realizing long bar feeding for turning equipment. Compact rotor design features low rotational inertia to realize ultra-fast acceleration and deceleration response.
- DRIVE‑CLiQ feedback interface
The matching encoder supports native DRIVE‑CLiQ communication. The electronic nameplate is stored inside the encoder, enabling automatic parameter identification once connected to S120 drives and drastically shortening on-site debugging time.
2. Core Technical Features & Selling Points
2.1 Outstanding dynamic performance for high-precision machining
As a synchronous permanent magnet motor, 1FE1 delivers high continuous torque and high overload capacity at low speed while maintaining ultra-high maximum rotating speed ranging from 12,000 rpm up to 40,000 rpm. Wide constant power speed range meets both heavy rough cutting and ultra-precision finish machining requirements. Low torque fluctuation guarantees superior workpiece surface finish.
2.2 Zero-backlash direct-drive structure cuts maintenance cost
Eliminate intermediate transmission parts such as drive belts, reduction gears and couplings. No mechanical clearance or transmission loss, improving spindle positioning accuracy and repeatability greatly. Machine owners save long-term spare part replacement and regular lubrication maintenance costs.
2.3 Compact layout optimizes machine design
Frameless split construction allows OEM manufacturers to customize spindle structure freely and reduce overall machine head size, helping designers develop compact, high-rigidity CNC equipment.
2.4 Stable water cooling design for continuous heavy-duty production
Full water-circulation cooling avoids overheating under non-stop S1 continuous operation, suitable for 24/7 automatic production lines in harsh workshop environments with high ambient temperature.
2.5 Seamless compatibility with Siemens S120 drive ecosystem
Plug-and-play coordination with SINAMICS S120 servo system is the biggest advantage for automation integrators. Standardized DRIVE-CLiQ connection simplifies wiring and reduces configuration error risks during installation.
3. Typical Application Scenarios
- High-speed vertical machining center & mold engraving milling machine
- Precision surface grinding, internal/external cylindrical grinding equipment
- Multi-task turn-mill composite machine C-axis servo indexing
- Aerospace, automotive and medical precision component processing equipment
Conclusion
Siemens SIMOTICS M 1FE built-in synchronous spindle motor is a professional direct-drive solution targeting mid-to-high-end CNC spindle market. Its unique frameless synchronous structure, superior dynamic property and perfect compatibility with S120 drives make it a preferred upgrade option for machine builders replacing old conventional spindle configurations. If you are sourcing original genuine 1FE series synchronous motors or need parameter selection consultation for spindle renovation, feel free to contact our technical support team.
