Citizen develops non-guide bush sliding head lathe
March 10th 2009
The non-guide bush version of the Citizen A20-VIICL was developed to provide competitive production of shorter length-to-diameter ratio components, up to 20mm diameter.
The normal Citizen sliding head lathe has a guide bush between the collet and cutting tool that provides additional support to the material as it is fed out by the headstock and minimises any tendency for deflection when machining longer components.
The sliding headstock pushes the material through the guide bush during the cutting process creating the z-axis motion and enables the cutting tool to be positioned as close to the support point of the bush as practical.
With a non-guide bush machine, parts with lower length-to-diameter ratios can also be accurately machined with all the advantages of the normal sliding head lathe.
Available from Citizen Machinery UK of Watford, the Citizen A20-VIICL is quick to reset and change over to a new component.
Due to its shorter axis strokes and high acceleration to rapid traverse rates of 32m/min, it has the capability to reduce cycle times against normal fixed-head lathes and turning centres.
The machine also cuts with two tools simultaneously on the front and reverse sides of a component and is much faster in operation due to Citizen-developed Streamline Control technology.
With a shorter working stroke, of up to 55mm, instead of 165mm of the normal A20, the length of the bar end remnant requirement is reduced.
Due to the shorter component lengths being machined and reduced bar end remnant requirement, the non-guide bush machine can be installed with a short barfeed unit that also contributes to a lower floor-space requirement.
The machine has a built-in 8,000rev/min spindle and sub-spindle with full c-axis and four driven tools having a top speed of 6,000rev/min.
One of the driven tool positions is also interchangeable to accept rotary, face or slitting style tools.
Full advantage of the heavier duty cast construction of the A20 range can be taken with heavier cuts, good absorption of vibration to accommodate the interrupted cut nature of the milling process and very effective thermal displacement characteristics.
This platform also enables feed rates to be maximised with consistent production cycles maintained over extended periods.
The non-guide bush Citizen A20, like the standard machine, incorporates Sandvik Coromant’s QS, the quick-change tooling system, developed in conjunction with Citizen, giving a tool change time within 40 seconds.
There are five turning tools, four directed to front-end machining and eight positions for back-end machining that can be split into four tools on each side of the spindle.
Four driven tools are powered by 0.75kW motors and positioned by the Fanuc-based Series 32i control, which utilises the Streamline Control technology.
The package also incorporates a completed workpiece outfeed conveyor and includes delivery, commissioning, training and a two-year warranty.