Citizen expands its single-turret lathe offerings to process larger bar diameters - Citizen Machinery

The twin-spindle, single-turret, fixed-head lathe programme offered by Citizen Machinery UK has been expanded with the introduction of a second generation of the Miyano BNX range. The first iteration, launched a decade ago, raised the capacity of this style of Miyano turn-milling centre from 42 mm bar capacity (BNA series) to 51 mm, while the second introduces a 65 mm capacity model as well. Additionally, LFV chipbreaking software has been added and the machines have been prepared for automation.

The rationale for a two-spindle, one-turret lathe configuration is to offer OEMs and subcontractors a high-productivity platform having multi-tasking and simultaneous machining capabilities approaching those of a twin-turret machine, but in a smaller footprint and at a more economical price. Engineered as EcoBalance machines, the BNX-51MSY and BNX-65MSY deliver high levels of productivity, while supporting Citizen’s commitment to sustainable, socially responsible manufacturing.

Despite having only one 12-station, Y-axis, live turret rated at 6,000 rpm / 25 Nm, the BNX-51/65MSY can perform complex rotational and prismatic machining operations thanks to the addition of independent X-axis movement of the sub-spindle. It means that the turret can be working on the main spindle and the sub-spindle simultaneously using Citizen’s proprietary superimposed machining. Machining at both 5,000 rpm work spindles at the same time is able to emulate the operation of a twin-turret lathe, greatly reducing cycle times.

A new function built into the operating system of the control is LFV (low-frequency vibration) chipbreaking software with different programmable modes. They cause oscillation of the slideway motions to break stringy swarf generated when machining malleable materials into short chips that are easy to clear from the working area. The problem of bird’s nesting and swarf entanglement around the tool or workpiece is eliminated, reducing scrap rates to virtually zero and promoting long periods of trouble-free running, including lights-out.

Automation and labour-saving features are integral to the BNX-51/65MSY’s design. Options include an in-machine unloader that transfers parts damage-free to the next process, a machine-mounted robot, automatic shutters, chip conveyors, and a choice of bespoke or standard automation systems such as collaborative pick-and-place robots. These features allow manufacturers to configure the machine for automated production, supporting both high-mix and high-volume applications.

Control is via Mitsubishi’s advanced M800LC-V CNC with a 15-inch touchscreen interface. This platform improves operability, provides expanded functions and promotes energy efficiency. Standard features include collision detection and a quick program check function, which enhance safety, reduce set-up times and simplify cutting cycle validation.