No strings attached

The new machining development was demonstrated on the latest Citizen Cincom L20-VIII CNC sliding head turn/mill centre, is fully programmable and can be applied to processes including turning, facing, drilling and even thread cutting operations.

The patented process of Low Frequency Vibration cutting (LFV) took some three years to develop and was amongst the latest concepts unveiled and demonstrated to the 3,000 visitors from around the world at last year’s CFA85 Innovative Manufacturing Event staged at Citizen’s Japanese headquarters. This technology has also been recently demonstrated this autumn by Citizen at AMB in Stuttgart and BiMu in Milan where high levels of interest in the potential for its application were shown by visitors.

Cutting trials both in Japan and Europe have already demonstrated significant improvements to cutting efficiency, not only on exotic materials but also, on difficult to chip ferrous and non-ferrous materials. In certain cases, the need for integrated high pressure coolant systems and fume extraction has been reduced or even replaced, thus creating additional savings from reduced power consumption and improved set up times.

When LFV has been applied, it has led to forecasts that productivity can be revolutionised when machining malleable materials, for instance, and especially plastics and copper which pose machinists with a constant challenge to maintain effective chip control.

LFV creates the advantage of aiding the production of small chips by finely fragmenting the swarf generated and eliminating the possibility of in-cut interference from stringy materials and especially when ‘birds-nesting’ is occurring. LFV technology also enables an increase in depth of cut and can improve surface quality even on very small diameters or very thin walled components.

While LFV can be applied to longitudinal turning, facing, taper or eccentric turning and drilling, which also includes small diameter and deep hole operations and especially when high peripheral speed is required, it can even be used to support and improve the thread cutting process. Indeed, it can be applied to most turning processes where a normal continuous contact is maintained between the cutting tool and the material which can have a dramatic influence on improving tool life and increase spindle uptime.

The LFV process is activated through a G-code in the CNC program enabling an on-demand initiation anywhere in the cutting cycle. The servo axes of the drive system are ‘vibrated’ in the direction of feed in phases involving tens of microns which are synchronised to the rotation of the machine spindle.

As a result, regular ‘air-cutting’ is introduced to the cycle which breaks swarf into small chips eliminating the problems associated with bird-nesting. It also reduces the tendency for built-up edge on the tool tip, extends in-cut life, helps reduce thermal effects in the cutting zone and can be an important factor in difficult to control processes such as deep hole drilling and even fine surface micro-machining.

Most important is that the LFV operation is fully programmable. This means that the machine will perform as a standard Citizen L20-VIII when in non-LFV mode.

At the launch events, LFV was demonstrated on the latest Citizen Cincom L20-VIII in machining sequences at both the main and secondary spindles. See the technology in action machining nickel silver and nylon at

Citizen Machinery UK www.citizenmachinery.co.uk