Starrag Bumotec s181

The Starrag Bumotec s181 is a dual-station 5-axis multi-technology machining center from Starrag’s Swiss Bumotec division, engineered for high-volume production of precision small parts in medical devices, watchmaking, connectors, and micro-mechanical assemblies. The twin-station configuration is the s181’s defining feature: while one station is machining, the other is loading and unloading, achieving near-continuous production with minimal non-cutting time.

The s181 provides X/Y/Z axis travels of 490 x 160 x 430 mm (19.3 x 6.3 x 16.9 in), with rapid traverse rates of 40 m/min and acceleration of 8 m/s² (0.9 g) on all linear axes. The main C-axis spindle handles bar stock up to 32 mm diameter with turning speeds up to 8,000 RPM and 11 kW peak power, while the high-speed milling spindle delivers 30,000 RPM standard with a 40,000 RPM option for micro-feature machining. The HSK-E40 or HSK-T40 tool interface provides the rigidity needed for precision milling at these speeds.

Tool capacity ranges from 30 positions standard up to 60 or 90 with optional magazine expansion, with tool-to-tool change times of 1.1 seconds. Through-spindle coolant at 100 bar is available as an option for deep-hole drilling and difficult material machining. The axis resolution of 0.0125 micrometers and C-axis resolution of 0.0001 degrees reflect the ultra-precision positioning capability designed into the machine.

The s181 runs on a Fanuc 31i-B5 control with a 15-inch display panel. The compact 3.5 m² footprint makes it exceptionally space-efficient for production cells. At 5,000 kg machine weight, the s181 is relatively light but well-damped for its precision class. New machines typically price between $500,000 and $800,000 depending on configuration.