Demonstrating for the first time at a UK exhibition, Citizen Machinery UK is launching its sixth generation of Miyano BNJ-SY6 fixed head, two spindle, twin-turret, turn-mill centres. The new machine features higher rigidity to both of its spindles, greater torque for driven tools, a Y-axis on the main turret and a totally new design of eight-station second turret that in particular, creates a milling capability.
With the launch of the new generation this becomes an important upgrade to one of Miyano’s best-selling models around the world amongst both OEM and subcontract users due to its ease-of-use, fast changeover, high orders of accuracy and overall production efficiency.
While the new BNJ machine is available in two capacity versions, the 51 mm bar capacity BNJ-51SY6 will be under power on the exhibition stand. Meanwhile, there is also a smaller capacity 42 mm (BNJ-42SY6) machine available. These bar / 6 inch power chuck machines provide significant flexibility with an overlapping capability of the main turret in X1-, Z1- and Y1- axes with both main and secondary spindles.
As both spindles and driven tool turrets can be run independently, simultaneous machining can be performed with either / or both turrets at each spindle. This level of machine flexibility means machining cycles can also be precisely balanced for maximum production efficiency and with the introduction of driven tools in the latest generation machine to the second turret, this significantly extends both the level of flexibility and capability.
The main spindle has 15 kW of power delivering 5,000 revs/min with increased rigidity through the incorporation of angular contact ball bearings and double-row cylindrical bearings to increase support to the rear of the spindle mainshaft. This increase in spindle rigidity maximises material removal especially when milling at the main turret when making use of the higher rated 2.2 kW of power and massive 25 Nm of torque available to the 6,000 revs/min driven tools.
The secondary spindle (X2- Z2-) has 7.5 kW 5,000 revs/min drive, also supported by the new eight-station second turret. This has four positions driven by 0.75kW, 10 Nm, 3,000 revs/min motors. Rapid traverse rates are 20 m/min in each axis and 12 m/min for the new 80 mm stroke Y1-axis on the main turret.
Improved setting is a further benefit with a wide opening access door adjacent to the mounting of the Fanuc FS 0iTF control. The control was previously sited above the working area guarding. Within the control, providing an interface with correction in X- and Z- axes, thermal displacement is achieved via strategic sensor positioning using the input of coefficients applied to oil or water-based coolants. Collision buffering is also standard as well as parts-catcher and an outfeed conveyor.
