Providing advantages for productivity improvements on shorter length parts

Citation

(2009), "Providing advantages for productivity improvements on shorter length parts", Aircraft Engineering and Aerospace Technology, Vol. 81 No. 2. https://doi.org/10.1108/aeat.2009.12781bab.002

Providing advantages for productivity improvements on shorter length parts

Article Type: Aerospace technologyFrom: Aircraft Engineering and Aerospace Technology: An International Journal, Volume 81, Issue 2

Developed to provide more competitive production of shorter length to diameter ratio components up to 20 mm diameter and especially providing additional savings when cutting expensive materials, the non-guide bush version of the Citizen A20-VIICL is also very competitively priced, has a very small footprint and is available as a ready-to-run machining package.

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.

It is reported that 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 giving high accuracy, excellent surface finish and high levels of flexibility involving turn-milling cycles.

Available from Citizen Machinery UK of Watford, the Citizen A20-VIICL is said to be quick to reset and change over to a new component and due to its shorter axis strokes and high acceleration to rapid traverse rates of 32 m/min, has the capability to significantly reduce cycle times against normal fixed-head lathes and turning centres.

The machine also claims the advantage of cutting with two tools simultaneously on the front and reverse sides of a component and is much faster in operation due to the high performance of the Citizen developed “Streamline Control” technology.

With a shorter working stroke, of up to 55 mm, instead of 165 mm of the normal A20, the length of the bar end remnant requirement is reduced that is able to create an important cost saving on expensive material. In addition, 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 floorspace requirement – considered an important factor in many machine shops.

The machine has the benefit of a built-in 8,000 rpm spindle and subspindle with full C-axis and four driven tools having a top speed of 6,000 rpm. 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 exclusively in conjunction with Citizen giving a tool change time within 40 sees. 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 0.75 kW motors and positioned by the Fanuc-based Series 32/control which very effectively utilises the “Streamline Control” software technology. This combination of control and software enables the creation of overlapped sequences to significantly reduce cycles times and introduces totally new levels of programming and operational flexibility.

The package also incorporates a completed workpiece outfeed conveyor and includes delivery, commissioning, training and a two-year warranty.

Details available from: Citizen Machinery UK Limited, Tel.: +44 (0) 1923 691500, web site: www.citizenmachinery.co.uk