SWISS DRIVE SYSTEMS
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Industries / Machine Tools

Machine Tools .

Today's metal-cutting and sheet-metal fleet is built on high-precision servo systems. Main spindles of machining centers and CNC lathes run across a wide speed range with torque control, feed drives must position to single-digit microns at 1–2 g accelerations, and hydraulic presses and press brakes demand clean, stable hydraulics and couplings able to absorb stamping shock loads. There is no room for consumer-grade components here — the bet is on brand-name servo drives, precision ball screws and dedicated couplings for press main drives.

CNC machining center in operation
Key figures
±0.003 mm
axis positioning and repeatability of a production CNC turn-mill center on servo drives and preloaded ball screws
93.5 %
NC share of Japan's metal-cutting machine production value in 2024 — feed and spindle drives have almost fully moved to servo systems
3.2 kHz
speed-loop bandwidth of a modern machine-tool servo drive — sets contour-following stiffness on finishing passes
$27.3 bn
China's machine-tool production value in 2024 — world's #1 for the 15th year running, the main component source for Russia's fleet

Context & trends

Machine tools have moved almost entirely to closed-loop servo systems: in Japan the NC share of metal-cutting machine production value reached 93.5 % in 2024 (JMTBA/METI), and an open-loop asynchronous feed drive is now the exception. Production turn-mill centers reach ±0.003 mm axis repeatability through servo motors with an absolute encoder and preloaded ball screws; accuracy here is set not by the motor alone but by the encoder–mechanical stiffness–drive bandwidth chain (up to 3.2 kHz speed-loop on modern series).

For Russia's metalworking fleet the key shift is sourcing toward China: in 2024 the PRC accounted for about a third of global metal-cutting machine production and held the #1 spot by value for the 15th year in a row ($27.3 bn, Gardner Intelligence). This covers not only finished machines but the component base — servo drives, ball screws, couplings, press hydraulics. A drive is judged on verifiable parameters: feed-gearbox backlash (arc-min), zero-backlash of the ball-screw coupling, positioning accuracy per ISO 230-2, power-pack oil cleanliness per ISO 4406 — that is the line between industrial and consumer-grade execution.

Typical tasks
01

Servo motors and electric motors

The key difference between metalworking drives and general-industry drives is closed-loop servo systems. The main spindle uses a servo motor with torque control and a wide regulation range (from 1 rpm on rough turning up to 12,000 rpm on finishing and grinding). Feed drives use servo motors with low rotor inertia, an absolute encoder and a holding brake that locks the axis on power loss. Key parameters: positioning accuracy (encoder counts), rotor inertia (J kg·m²), torque-loop bandwidth (≥ 2 kHz for modern series) and compatibility with EtherCAT/Mechatrolink/CANopen fieldbus through which the CNC controls the axes.

Servo drives for main spindles of machining centers and lathes

Servo motors with built-in encoder and forced cooling for the main spindle. Torque must hold across a wide speed range: at low speeds for heavy turning, at high speeds for finishing. Inovance MS1H and Wolong WGM water-cooled series deliver 7.5–90 kW at speeds up to 12,000 rpm and low-speed torque up to 600 N·m.

  • 7.5–90 kW power, 1:10,000 control range
  • 23-bit absolute encoder (8,388,608 pulses/rev)
  • Torque-loop bandwidth ≥ 2 kHz
  • Forced liquid or air cooling (IC416/IC81W)
  • Bearing protection against shaft currents (insulated non-drive-end bearing)

X/Y/Z feed servo drives via ball screw

Precision servo motors with low rotor inertia and built-in holding brake. They couple to the ball screw directly via a bellows coupling or through a 1:3–1:10 feed gearbox. Low rotor inertia matters for fast reversals during contour following, and a holding brake is mandatory on the vertical Z axis so the spindle does not drop on power loss. Inovance SV660 / WOLONG WPM cover 0.4–7 kW.

  • 0.4–7 kW power, 1.3–22 N·m torque
  • Low rotor inertia (J ≤ 5 × 10⁻⁴ kg·m²)
  • Built-in 24 V holding brake on the Z axis
  • 300 % overload for 3 s (for accelerations)
  • EtherCAT or Mechatrolink-III fieldbus to the CNC controller

Flywheel motors for press shears and crank presses

Mechanical shear-type presses use a 75–500 kW asynchronous motor to spin the flywheel up to working speed. Working-stroke energy comes not from the motor but from the flywheel's stored kinetic energy; in steady state the motor only tops up 10–20 % to recover speed. No VFD start is required here — a general-industrial motor with high starting torque or a soft starter is sufficient.

  • 75–500 kW power, 6 or 8 poles
  • Starting torque ≥ 1.8 × rated
  • Insulation class F, IP55
  • Compatibility with the press friction clutch (heavy extended shaft)
  • S6 duty capability (continuous with short-time load)

Motors for press power packs and coolant systems

Standard 5.5–200 kW asynchronous motors driving axial-piston and vane pumps in hydraulic power packs. S1 continuous duty, IP55, class F. Large hydraulic presses use several pumps on separate motors — this allows shutting down part of the pumps in low-flow cycles and saving energy. Variable-output presses use VFD start via Invt or Inovance drives.

  • 5.5–200 kW power, 4 or 6 poles
  • Insulation class F, IP55, S1 continuous duty
  • Pump compatibility via IEC B3/B5 flange
  • Inverter-duty option (NEMA MG1 Part 31) for VFD operation
  • Built-in PTC thermal protection

High-speed motors for grinding and tool-grinding machines

Grinding operations need spindles running at 6,000–15,000 rpm with fine rotor balancing (G1.0 or better). Dedicated servo motors or 1.5–15 kW high-frequency asynchronous motors (200–400 Hz) with G2.5 balancing are used. Bearings are ceramic or forced oil-lubricated. A specific requirement is low no-load vibration — otherwise vibration marks transfer to the ground surface.

  • 6,000–15,000 rpm speed
  • Rotor balancing per ISO 1940 G1.0–G2.5
  • Long-life bearings (ceramic or oil-mist)
  • No-load vibration ≤ 1.8 mm/s (zone A per ISO 10816)
  • High-frequency VFD compatibility
02

Gearboxes and gear motors

Gearboxes play a supporting role in metalworking: spindle main drives are increasingly direct (motor-spindle without a gearbox), but gear motors stay on feed drives of large gantries, buffers, tool magazines and material feed for shears. The critical parameters here are backlash (no more than 1–3 arc minutes for precision feeds), efficiency under high accelerations, low inertia referred to the output shaft, and flange compatibility with servo motors.

Low-backlash planetary feed gearboxes

Precision planetary gearboxes 1:3–1:100 with 1–3 arc-min backlash, used to couple servo motors to ball screws and rack-and-pinion drives of gantry machines. Low inertia and high torsional stiffness preserve the position-loop bandwidth of the servo drive. On large gantry plasma cutters they are used to synchronize the two Y axes.

  • 1:3 – 1:100 ratio
  • Backlash ≤ 3 arc-min (precision class)
  • Torsional stiffness ≥ 10 N·m/arc-min
  • Servo motor flange compatibility (DIN or proprietary chart)
  • Low referred inertia (J ≤ 1 × 10⁻⁴ kg·m²)

Gear motors for buffers, chip conveyors and coolant feed

Standard industrial helical-bevel (K-series) or in-line (R-series) gear motors for auxiliary drives: chip conveyors, workpiece chain conveyors, coolant feed, tool magazine buffers. Boneng K and HB series 0.55–11 kW cover the full set of typical tasks.

  • 0.55–11 kW power, 5–200 ratio
  • Service factor ≥ 1.5
  • IP55 protection (IP66 in coolant zone)
  • Compatibility with 24 V brake
  • Seal resistance to oil-based coolants

Rack-and-pinion gantry drives for plasma and oxy-fuel cutters

On gantry cutting machines (plasma, oxy-fuel, laser) gantry drives run through a rack and pinion. Precision planetary gearboxes with an output pinion are used, with low backlash and high efficiency. Rack length reaches 10–24 m, so the stiffness of the gearbox-to-carriage mount and rack alignment accuracy are critical.

  • Output pinion with module 2–4 mm
  • Installed backlash ≤ 0.05 mm along the arc
  • Spring-loaded mounting to eliminate clearance
  • 1:5–1:20 ratio
  • Adjustable center distance

Sheet feed gearboxes for guillotine shears and press brakes

Servo drives with 1:10–1:50 planetary gearboxes on the back-gauge stops. Stop positioning accuracy defines the cut-length accuracy of the sheet — typically ±0.05 mm over 4 m. Backlash here must not exceed 1 arc-min and reverse repeatability must be high.

  • Stop positioning accuracy ±0.05 mm
  • Backlash ≤ 1 arc-min (high-precision class)
  • Reverse repeatability ≤ 0.02 mm
  • 1:10–1:50 ratio
  • Low thermal deformation (operating up to 80 °C)
03

Couplings for main drives and spindles

On press equipment the coupling between the flywheel and the eccentric shaft transmits stamping shock loads of tens and hundreds of tonnes — it is the most heavily loaded coupling in the machine fleet. Yongjing drum gear couplings are used for rigid connection with misalignment compensation, and Longxuan flexible couplings are used for vibration damping on finishing machining centers and grinding spindles. Ball-screw feeds use zero-backlash bellows or disc-pack couplings — no backlash is acceptable here.

Gear couplings for press and shear main drives

Yongjing GIICL drum-type double-engagement gear couplings transmit torque from flywheel to press eccentric shaft under stamping shock loads. The crowned tooth profile compensates angular misalignment up to 1°30′ after thermal expansion of housings and foundation settling. Grease lubrication via a fitting, replaced every 6 months.

  • 50–800 kN·m torque
  • Angular compensation up to 1°30′
  • Compatibility with flywheel and eccentric flange
  • G6.3 balancing at peripheral speeds > 15 m/s
  • Service factor for stamping loads ≥ 2.0

Flexible pin couplings for spindle vibration damping

Longxuan LX/LMC flexible couplings with elastomer bushings reduce vibration amplitude of the main motor under interrupted cutting (milling with entry/exit) and compensate small shaft misalignment. They sit between the main spindle motor and the gearbox or belt-drive pulley. Elastomer service life is at least 30,000 hours.

  • 0.5–25 kN·m torque
  • Radial misalignment compensation up to 0.5 mm
  • Torsional damping capability 1–2°
  • Elastomer life ≥ 30,000 h
  • Bushing replacement without coupling removal

Bellows and disc-pack couplings for ball-screw feeds

Zero-backlash metal couplings between the servo motor and the ball screw. Bellows couplings suit long shafts with greater misalignment compensation; disc-pack couplings suit short shafts with high torques. Torsional stiffness must exceed 200 N·m/rad, otherwise position-loop bandwidth is lost and oscillations appear on finishing passes.

  • 5–500 N·m torque
  • Zero-backlash design
  • Torsional stiffness ≥ 200 N·m/rad
  • Axial misalignment compensation ±0.5 mm
  • G2.5 balancing for speeds up to 6,000 rpm

Press combined clutch-brake units

A combined clutch-brake unit on the press eccentric shaft — engages the flywheel with the shaft on the working stroke and clamps the shaft with the brake during idle. Actuation is pneumatic or hydraulic, engagement time 100–200 ms. Used on crank presses and press shears. Friction-lining wear is monitored via piston travel; once the limit is reached, the disc set must be replaced.

  • Engagement time ≤ 200 ms
  • 5–6 bar pneumatic control or hydraulics
  • Torque reserve 1.75–2.0 × press rated stroke
  • Lining wear monitored via limit switch
  • Press eccentric-shaft fit compatibility
04

Hydraulic components for presses and press brakes

Hydraulic presses and press brakes are above all a hydraulic system: pump → manifold → proportional valves → cylinders. Ram travel accuracy (typically ±0.01 mm on a 100 tonf press) and force stability depend on valve quality and oil cleanliness. On press brakes with two-cylinder synchronization (mechanical torsion bar or CNC via linear scales), valves must have high repeatability and low thermal drift.

Power packs for 75–1,500 tonf hydraulic presses

Complete Donly 5.5–200 kW power packs with variable-displacement axial-piston pumps, heat exchanger, fine filtration and proportional force-control valves. Hot-stamping presses add a water oil cooler and tank heating for winter start-up. Donly is SDS's signature competence in power packs, including build-to-print assembly to customer drawings.

  • 5.5–200 kW power, 16–32 MPa pressure
  • Variable-displacement axial-piston pump
  • 10 µm fine filter with clogging indicator
  • Air or water oil cooler
  • Tank with level gauge, thermometer and heating up to 35 °C

Proportional valves for press force control

Huade DBE/2FRE/4WRE proportional pressure and flow valves for CNC-programmed press force and ram speed control. Used on CNC press brakes and in two-cylinder synchronization systems on long press brakes. Pressure regulation accuracy ±1 % of rated, response time 30–80 ms.

  • Pressure up to 31.5 MPa, flow 30–500 l/min
  • Regulation accuracy ±1 % of rated
  • Response time 30–80 ms
  • Control signal 0–10 V or 4–20 mA
  • IP65 protection, oil temperature -20…+80 °C

Cylinders and valves for CNC machine guideways

Hydraulic cylinders for table clamping, rotary indexers and Z-axis counterbalance on large machining centers. Standard Ini unloading and pressure-reducing valves control clamp/unclamp. On large horizontal boring mills the spindle headstock weight is counterbalanced by hydraulic cylinders held at constant pressure.

  • 16–25 MPa pressure
  • Cylinders per ISO 6020/6022 or proprietary
  • Pressure-reducing valves with ±2 % accuracy
  • Seals for long cycle life (≥ 2 million cycles)
  • Compatibility with HLP 46 / HM 46 oil

CNC press brake systems with synchronization

Hydraulic press brakes with two cylinders require synchronized motion via two linear scales (right and left ram ends). Control through Huade proportional valves with feedback delivers ram parallelism of ±0.02 mm over 4 m, which is critical for bend quality on long sheets.

  • Ram parallelism ±0.02 mm over 4 m
  • Magnetostrictive linear scales, 0.01 mm
  • Proportional valves with < 50 ms response
  • Software control from CNC controller (DA-66T / Cybelec)
  • Two-channel emergency stop (category 4)

Hydraulic systems for plasma and oxy-fuel cutters

Large oxy-fuel and plasma cutters with elevating tables use compact 5.5–22 kW hydraulic systems for grate lift, sheet clamping and slag-bin extraction. Components include Ini manifolds and directional valves, filters with vacuum clogging indicator. Oil cleanliness is critical: class no worse than 18/16/13 per ISO 4406.

  • 5.5–22 kW power, 16 MPa pressure
  • Oil cleanliness 18/16/13 per ISO 4406
  • 4/3 directional valves with 24 V DC solenoid control
  • 10 µm return-line filters
  • Power-pack protection class IP54
SDS solutions
Equipment for the industry92
Image credits: Psychlist1972 (CC BY 2.0) · Wikimedia Commons (CC BY 3.0) · Historic American Engineering Record (HAER) (Public domain) · Wikimedia Commons (Public domain) · Graibeard (CC BY-SA 3.0)
Gallery
INOVANCE EASY-PLC
WOLONG OLI
INVT DA180A
YONGJING GICL
LONGXUAN GIICL
DONLY DLBE
HUADE 4WE
INI IAP