Citizen Sliding-Head Lathe Gains Patented Chipbreaker Software

Citizen Machinery has incorporated its LFV (low frequency vibration) chipbreaking technology into the 12-axis, 25 mm capacity Cincom D25-VIII CNC sliding-headstock turn-mill centre. It considerably enhances the lathe's production flexibility and efficiency, especially when turning difficult-to-chip materials that traditionally produce long, stringy swarf, such as copper, plastics and steels with high alloy content. LFV can also be applied to grooving, thread cutting and drilling.

The latest D25-VIII features the Industry 4.0-ready Mitsubishi 800 CNC system with touch screen and QWERTY keyboard. Providing three axis control groups so that three tools can be in cut at the same time, as well as simultaneous 5-axis machining capability for producing complex parts, it is an advanced control whose operating system incorporates the patented LFV software.

When the technology is applied to a cutting cycle, it encourages chipbreaking without the need for high pressure coolant by rapidly oscillating the tool in two axes in synchronisation with the rotation of the machine spindle. This is in contrast to the intermittent chipbreaking action being programmed into a cycle as a macro, which can generate heat and cause tool tips to wear prematurely.

In addition to offering other advances in the machine’s operational functions, the simultaneous 5-axis control ensures the contact angle between each engaged cutter and the component is maintained during the production of complex parts, enhancing surface finish, reducing cycle times and extending tool life.

The Cincom D25-VIII LVF has gang toolposts in front of and behind the spindle centreline, with Z-axis motion provided on the rear carrier to allow balanced turning, milling or drilling, or simultaneous rough and finish turning. There is also a 135-degree swivelling B-axis on the front post carrying up to four driven tool on either side to service both the main and counter spindle. This configuration is believed to be a world first.

A manually set tilt spindle can be mounted on the rear gang carrier and the back toolpost. Together with the major advantage of programmable control of chip size, the tilt spindle has the ability to help eliminate deflection when turning very small, precise diameters. An optional, two-axis, opposite tool carrier next to the counter spindle provides a facility for reverse end machining at the main spindle.

For executing complex cycles, operational flexibility is maximised by deploying up to 59 tools in the cutting area, coupled with the advantage of being able to remove the guide bush for more economical material usage when producing shorter components up to 2.5 times bar diameter.

The main and counter spindle are rated at 5.5 kW and 3.7 kW respectively and both have a maximum speed of 10,000 rpm. The gang driven tool stations are powered by 2.2 kW drives with maximum speeds of 9,000 rpm, while live cutter speed in the back toolpost is up to 6,000 rpm. Rapid traverse rates are 32 m/min, with 24 m/min available in the Z-axis of the rear gang toolpost.

The machine footprint is compact, requiring just 1.5 metres by 2.55 metres of space on the shop floor. To meet LFV technology demands, the 3.4-tonne machine is mounted on six legs and drive is through 25 mm diameter ballscrews, adding a massive 16 per cent to the rigidity factor of the lathe.

A fully opening guard gives excellent access to the work zone for easy setting and an additional sliding door is incorporated at the rear of the machine. Twin coolant pumps are included with a 200 litre tank. A 90 mm wide workpiece conveyor is standard.