GF Machining Solutions 5-Axis Machining Centers

GF Mikron MILL S 400 U

$350,000 - $480,000 Updated 2025-03-15

Key Specifications

X Travel

500 mm (19.7 in)

Y Travel

245 mm (9.6 in)

Z Travel

360 mm (14.2 in)

Max Spindle

42,000 RPM (30,000 RPM option)

Spindle Taper

HSK-E40

Tool Capacity

68 tools (168 optional)

Overview

The GF Mikron MILL S 400 U is GF Machining Solutions' mid-range speed-class 5-axis machining center, built for precision mold finishing and electrode production with full 5-axis simultaneous capability. With 500 x 245 x 360 mm (19.7 x 9.6 x 14.2 in) of X/Y/Z travel and spindle options up to 42,000 RPM in HSK-E40, this machine brings the S series' high-speed finishing DNA into the 5-axis world.

The spindle choices include 30,000 and 42,000 RPM Step-Tec units in HSK-E40, delivering 13.5 kW and 8.8 Nm of torque. At 42,000 RPM, micro-diameter cutters reach optimal SFM on hardened steel and graphite, enabling the kind of surface finishes that reduce or eliminate hand polishing on mold cavities and cores. The polymer granite base provides the vibration damping that makes these speeds productive rather than destructive.

Rapid traverse is an impressive 61 m/min (2,402 ipm) with the S designation, minimizing non-cutting time. The 68-pocket standard tool magazine (168 optional) handles complex 5-axis programs with extensive tooling requirements. The trunnion table accepts workpieces up to 25 kg (55 lb) on System 3R MacroMagnum 156 or ITS 148 pallets.

The Heidenhain TNC 7 or Siemens SINUMERIK ONE control provides advanced 5-axis kinematic functions including automatic calibration, volumetric compensation, and sophisticated look-ahead algorithms. The machine weighs 7,000 kg (15,432 lb) and features integrated thermal management to maintain accuracy during continuous 5-axis finishing operations.

New MILL S 400 U machines price between $350,000 and $480,000. The machine competes with the Makino DA300, Hermle C 250, and DMG Mori DMU 50 in the precision 5-axis mold finishing segment. For shops that need 5-axis access to mold cavities with the S series' signature speed-class surface finish capability, the S 400 U is the primary choice.

Full Specifications

Parameter	Value
X-Axis Travel	500 mm (19.7 in)
Y-Axis Travel	245 mm (9.6 in)
Z-Axis Travel	360 mm (14.2 in)
Max Spindle Speed	42,000 RPM (30,000 RPM option)
Spindle Taper	HSK-E40
Spindle Motor Power	13.5 kW (18 hp)
Spindle Torque	8.8 Nm (6.5 ft-lb)
Tool Capacity	68 tools (168 optional)
Table Size	System 3R MacroMagnum 156 / ITS 148 pallet
Max Work Weight	25 kg (55 lb)
Rapid Traverse Rate	61 m/min (2,402 ipm)
CNC Control	Heidenhain TNC 7 / Siemens SINUMERIK ONE
Machine Weight	7,000 kg (15,432 lb)
Machine Base	Polymer granite

Specifications sourced from gfms.com — verified 2026-03-28

Strengths & Limitations

Strengths

42,000 RPM Step-Tec spindle delivers speed-class surface finishes on 5-axis mold cavities and electrode work
61 m/min rapid traverse minimizes non-cutting time, maximizing productivity on complex multi-feature 5-axis programs
168-pocket expanded tool magazine supports extensive tooling for complex programs without manual intervention
Polymer granite base with thermal management enables consistent accuracy during continuous 5-axis finishing
Choice of Heidenhain TNC 7 or Siemens SINUMERIK ONE — both top-tier 5-axis control platforms
System 3R pallet integration enables automated 5-axis mold finishing and electrode production

Limitations

245 mm Y-axis travel is notably short, restricting workpiece depth and limiting some 5-axis approach angles
25 kg max workpiece weight is very restrictive — only suitable for small mold inserts and electrodes
HSK-E40 taper and 8.8 Nm torque limit this to finishing and semi-finishing only — zero roughing capability
Premium pricing at $350K-$480K for a machine with limited workpiece capacity requires high-value finishing work to justify
Specialized mold finishing focus means limited versatility for general 5-axis production work

Best For

5-axis mold finishing requiring speed-class surface quality on complex cavity and core geometries Electrode production requiring 5-axis access for complex electrode forms with micro-detail features Medical implant finishing where 5-axis surface contouring on small components demands the highest finish quality Watch and luxury goods manufacturing requiring 5-axis precision on small, intricate components Automated 5-axis finishing cells using System 3R for lights-out mold component production Turbine blade and vane finishing where aerodynamic surfaces demand exceptional 5-axis surface quality

Frequently Asked Questions

01 What does a new GF Mikron MILL S 400 U cost?

New MILL S 400 U machines price between $350,000 and $480,000 depending on spindle choice, control, tool magazine size, and automation. The 168-pocket expanded magazine adds approximately $20,000-$30,000. System 3R automation packages add $60,000-$150,000. Used machines from 2016-2020 trade between $150,000 and $300,000.

02 Why is the Y-axis only 245mm?

The S 400 U is designed around pallet-based mold insert and electrode work where parts are typically fixtured on System 3R pallets within a compact envelope. The machine prioritizes spindle speed, acceleration, and surface finish over raw travel. For larger Y-axis travel with 5-axis capability, GF offers the MILL S 600 U with 600 mm of Y travel.

03 How does the S 400 U compare to the Makino DA300?

Both target precision 5-axis mold finishing. The Makino DA300 offers a 20,000 RPM HSK-A63 spindle with higher torque (120 Nm), making it more versatile for combined operations. The S 400 U counters with 42,000 RPM for superior fine finishing and the polymer granite base for better vibration damping. The DA300 handles more material removal; the S 400 U achieves better surface finishes. Pricing is comparable.

04 Can the S 400 U work with the X 400 U high-dynamics version?

The MILL X 400 U variant uses linear motors instead of ballscrews, achieving up to 100 m/min rapids and significantly higher acceleration. This X designation adds roughly $50,000-$80,000 to the price but dramatically reduces non-cutting time. For high-volume electrode production, the X 400 U variant is worth the premium.

05 What's the realistic surface finish capability?

On hardened steel (50-62 HRC), expect Ra 0.1-0.15 µm consistently with appropriate tooling and cutting parameters. On graphite and copper electrodes, Ra 0.1 µm is standard. These finishes significantly reduce or eliminate hand polishing on mold cavities, which is the primary ROI justification for the machine's premium price.