Components are becoming more and more complex, and drawing tolerances ever-tighter. The ability of a CNC turn-mill centre’s live turret tooling to move in the Y axis, as well as in X and Z, has therefore become increasingly important to facilitate high accuracy, one-hit machining. If travel in only the latter two axes is available, the milling of flats, deburring, and the possibility of machining pockets and off-centre features in-cycle, are either difficult or impossible.
The latest Miyano fixed-head lathe from Citizen Machinery UK to feature a Y-axis turret, in this case with all 12 tool stations driven, is the new BND-64SY for turning parts from bar up to 64 mm diameter. Joining a similar model that accepts bar up to 51 mm diameter through the main spindle, the 4.75-tonne machine is a mid-range, multi-purpose, twin-spindle turning centre. A ribbed monobloc bed slanted at 30°, and carrying precision-scraped square guideways, provides high rigidity, optimal thermal and mechanical stability, and excellent vibration damping, says Citizen.
These characteristics result in highly accurate machined components and longer service life of the tools, which can mount flexibly in the turret using multi-tool holders in any position. The robustness of machine construction allows the turning and milling of tough alloys and metals in their hardened condition, even when taking intermittent cuts. Polygon turning and thread milling are both options in the FANUC 0i-TD control, which is capable of simultaneous four-axis interpolation.
The specification of the Japanese-built machine includes turret travels in X/Y/Z of 175/75/435 mm, some 530 mm of sub-spindle axis travel, and up to 20 m/min rapid feed rate.
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