Roku-Roku HC-658

$250,000 - $400,000 Updated 2026-03-14

Key Specifications

X Travel

23.6 in

Y Travel

19.6 in

Z Travel

15.7 in

Max Spindle

32000 rpm

Spindle Taper

HSK-E40

Tool Capacity

20 tools

Overview

The Roku-Roku HC-658 is a high-speed precision vertical machining center from one of Japan's most specialized graphite and electrode machining manufacturers. Roku-Roku (also written as Roku Roku or 6-6) has carved out a distinctive niche building machines optimized for graphite electrode machining, copper electrode finishing, and ultra-precision mold cavity work. The HC-658 with 650 x 500 x 350 mm (25.6 x 19.7 x 13.8 in) X/Y/Z travel is their mid-size workhorse, delivering the combination of high spindle speeds, fine surface finishes, and dust management that graphite machining demands.

The machine is built around a high-speed spindle running to 30,000 rpm standard (40,000 rpm optional) with an HSK-E40 interface. The small-taper HSK interface and high RPM are purpose-built for the small-diameter ball nose end mills (0.2-6 mm) used in graphite electrode finishing. The direct-drive spindle motor produces 5.5 kW (7.4 HP) continuous — modest by machining center standards, but graphite machining generates relatively low cutting forces. What matters is spindle speed, runout (under 1 micron at the nose), and thermal stability during extended finishing cycles.

Roku-Roku machines are known for their attention to the unique challenges of graphite machining. The HC-658 includes a sealed machining enclosure with dedicated dust extraction designed specifically for graphite particles, which are abrasive and conductive — a dangerous combination for exposed linear scales and ballscrews. All critical components are sealed and protected. The linear motor drives on all three axes provide rapid traverse of 60 m/min with acceleration that enables smooth high-speed contouring essential for complex electrode geometries.

Positioning accuracy is +/-2.0 microns with repeatability of +/-1.0 microns. The Fanuc 31i-B5 control with AICC-2 high-speed contouring provides the path control needed for complex 3D electrode shapes. The 20-tool ATC supports the relatively few tools typically used in electrode finishing. The HC-658 competes with the Makino EDAF series, Sodick MC series, and GF Mikron HSM series in the graphite/electrode machining segment. Roku-Roku's advantage is their singular focus on this application — every design decision optimizes graphite and precision electrode work.

Full Specifications

Parameter	Value
X-Axis Travel	23.6 in
Y-Axis Travel	19.6 in
Z-Axis Travel	15.7 in
Table Size	800 x 500 mm (31.5 x 19.7 in)
Max Table Load	500 kg (1,102 lb)
Spindle Speed	30,000 rpm (40,000 rpm optional)
Spindle Taper	HSK-E40
Spindle Motor	5.5 kW (7.4 HP) continuous
Spindle Runout	< 1.0 um at spindle nose
Positioning Accuracy	+/-2.0 um
Repeatability	+/-1.0 um
Rapid Traverse Rate	60 m/min (2,362 ipm) all axes
Drive Type	Linear motors (all axes)
Tool Capacity	20 tools
CNC Control	Fanuc 31i-B5 with AICC-2
Dust Extraction	Integrated graphite dust management system
Machine Weight	5,500 kg (12,125 lb)
Machine Travels X X Y X Z In	23.6 x 19.6 x 15.7 (600 x 500 x 400)
Max Spindle Speed	32000 rpm
Spindle Hp	8.4
Spindle Lubrication	Grease Packed
Tool Changer Size	30 Position Standard
Positioning Accuracy Repeatability In	±0.000060/±0.000020 (±1.5/±0.5)
Table Work Area X X Y In	30.0 x 20.0 (760 x 500)
Table To Spindle Nose Distance In	7.8 ~ 23.6 (200 ~ 600)
Max Workpiece Weight Lb	440 (200)
Coolant Tank Capacity Gal	None
Table Height From Floor In	31.5 (800)
Actual Measured Circularity In	0.000078 (2.0)
Spindle Air Purge	Standard
Air Blast Through Spindle	Standard
Oil Mist With Collector	Optional
Linear Scales X Y Z Axes	Heidenhain 0.00001mm Standard
Rapid Traverse Speed In Min	787 (20)
Cutting Speed In Min	787 (20)
Dust Collection System	Amano PiE-30 Standard
Machine Weight Lb	12,100 (5490)
Machine Height In	113 (2870)
Required Floor Space Machine Unit In	118 x 118 (3000 x 3000)
Control Unit	Fanuc 31i-A5 Super High-Speed Processor and Al Contour Control II
Power Requirements Kva	200 ~ 220V 22KVA
Air Supply	21 cu.ft./min @ 72 psi
X	23.6 in
Y	19.6 in

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

Strengths & Limitations

Strengths

Purpose-built for graphite electrode machining with integrated dust extraction and sealed critical components
30,000 rpm standard spindle (40,000 optional) with sub-micron runout enables fine electrode finishing with micro tools
Linear motor drives on all axes provide 60 m/min rapids and smooth high-speed contouring for complex electrode geometries
+/-2.0 um positioning accuracy ensures electrodes match CAD geometry precisely for accurate EDM burn results
HSK-E40 interface provides excellent rigidity-to-weight ratio for the small tools used in electrode finishing
Roku-Roku's singular focus on graphite machining means every design detail is optimized for this specific application

Limitations

5.5 kW spindle power limits the machine to light cutting — not suitable for heavy milling in steel or cast iron
HSK-E40 taper restricts tool selection to small-diameter tooling, limiting versatility for general machining
Roku-Roku brand is relatively unknown outside the mold/die industry, which affects resale value and service accessibility
20-tool ATC is minimal, though electrode machining typically uses fewer tools than general milling applications
350 mm Z-travel limits part height, restricting the machine to shallow electrode and mold work

Best For

Mold shops machining graphite electrodes for sinker EDM operations, particularly complex 3D shapes and fine-detail electrodes Die shops finishing copper and copper-tungsten electrodes requiring sub-micron surface quality Precision mold cavity finishing in pre-hardened and hardened tool steels using small ball nose end mills Connector and electronics mold manufacturers producing micro-detail electrodes with features under 0.5 mm Shops standardizing graphite electrode production on a purpose-built platform rather than adapting general VMCs Any application requiring high-speed micro-milling with sub-micron spindle runout and precision path control

Frequently Asked Questions

01 What does a Roku-Roku HC-658 cost?

New HC-658 machines typically price between $250,000 and $400,000 depending on spindle speed option (30K vs 40K rpm) and accessories. The 40,000 rpm spindle option adds a significant premium. Used Roku-Roku machines are rare on the North American market.

02 Can the HC-658 machine materials other than graphite?

Yes. The HC-658 handles copper, copper-tungsten, aluminum, and pre-hardened steels up to about 50 HRC effectively. However, the 5.5 kW spindle and HSK-E40 taper limit it to light cuts — it is not a general-purpose machining center for heavy steel milling.

03 Why is graphite dust management so important?

Graphite dust is both abrasive and electrically conductive. Without proper containment, it damages linear scales, infiltrates ballscrew seals, shorts electrical components, and creates health hazards. The HC-658's integrated dust extraction and sealed construction address all of these issues.

04 How does the HC-658 compare to a Makino EDAF2?

Both target graphite electrode machining. The Makino EDAF2 is widely recognized and well-supported in North America with strong resale value. The Roku-Roku HC-658 offers linear motors for higher dynamics and Roku-Roku's deeper specialization in graphite machining. The Makino may be the safer choice for service; the Roku-Roku may edge ahead on graphite-specific performance.

05 Is the 40,000 rpm spindle option worth the upgrade?

For shops producing micro-detail electrodes with tool diameters below 0.5 mm, the 40,000 rpm spindle maintains proper surface speeds that the 30,000 rpm spindle cannot reach. For electrodes using tools above 1 mm diameter, the standard 30,000 rpm is sufficient.