Roku-Roku HC-878

The Roku-Roku HC-878 is a high-speed vertical machining center purpose-built for graphite electrode machining and precision mold finishing. Roku-Roku has carved out a niche in the Japanese market as the specialist for graphite and copper electrode milling, and the HC-878 represents their latest thinking on combining high spindle speeds with exceptional rigidity in a compact footprint. With X/Y/Z travels of 800 x 700 x 400 mm and a 30,000 RPM direct-drive spindle as standard, it handles everything from roughing graphite blocks to finishing intricate electrode geometries.

The machine's linear roller guideway construction on all three axes delivers the combination of speed and stiffness that graphite electrode work demands. The direct-drive spindle eliminates belt vibration and gear train backlash, which matters when you're chasing single-digit micron accuracy on fine-detail electrodes. Positioning accuracy is rated at +/-2 um with repeatability of +/-1 um, putting it in the same class as competing machines from Makino and Sodick but at a more accessible price point for dedicated electrode shops.

Dust management is a serious consideration on any graphite machining center, and Roku-Roku addresses it with an integrated vacuum extraction system and fully enclosed machining chamber. The sealed spindle bearings and covered guideways protect precision components from abrasive graphite dust that would otherwise degrade accuracy over time. This is not an afterthought — the entire machine architecture is designed around dry graphite machining from the ground up.

The Fanuc 31i-B5 control comes standard with high-speed surface control (AICC II) and nano-smoothing for superior surface finishes on complex 3D electrode forms. The 60-tool ATC magazine supports extended unattended runs, and the tool length measurement system automatically compensates for tool wear during long electrode roughing cycles. Roku-Roku machines are well-established in Japanese mold shops and increasingly found in European and North American facilities that specialize in die-sink EDM electrode production.