Fanuc wire EDM C-series electronic and software developments

Citation

(2004), "Fanuc wire EDM C-series electronic and software developments", Aircraft Engineering and Aerospace Technology, Vol. 76 No. 6. https://doi.org/10.1108/aeat.2004.12776fab.005

Fanuc wire EDM C-series electronic and software developments

Fanuc wire EDM C-series electronic and software developments

Keywords: Machine tools, Electronics, Software

The 600 Group informs us that with the launch of A1 pulse control, feed rates can be increased by up to 40 per cent on the latest Fanuc Robocut Alpha-/ C series of wire electro-discharge machines. And, when combined with the latest Nano Interpolation development giving NC commands to the machine servodrives with an ultra-fine pitch of 0.001 mm, high speed cutting up to 330 mm²/min using 0.3mm brass wire can be performed with a high precision capability such as holding roundness to within 1.2 µ on a 30 mm diameter hole to a surface finish of 0.7 µm (Figure 1).

Figure 1 Fanuc Robocut's new Pulse Control and Nano Interpolation enables feed rates to be increased by up to 40 per cent

The two new robocut machines in the C-Series from 600 Centre of Shepshed, Loughborough, UK, are available in the 0 version, having cutting strokes of 320 mm × 220 mm × 180 mm and a 500 kg table loading or the larger capacity I variant, having cutting strokes of 550 mm × 370 mm × 310 mm and a 1 tonne table loading.

Both machines feature the latest Fanuc 180 is – WB advanced control. This system also supports the claims of the world's fastest disconnection to reconnection automatic wire feed (AWF) in just 12 s using thermal melting techniques.

The developments of the patent pending Al pulse control are said to enable precise monitoring of the number of pulses applied to the cutting process and responsive issue by the CNC control of velocity commands. This reaction enables the energy density and discharge gap between wire and workpiece to be optimised and kept uniform throughout the cutting process. As a result problems such as wire breakage due to concentrated discharge are said to be eliminated and with the increased smoothness of axis motions, accommodates initial penetration into the workpiece by the wire and overcomes any variation at the point of cut. This enables feed rates to be improved by up to 40 per cent over conventional Fanuc wire machines with less likelihood of wire breakage.

As Nano Interpolation software distributes positioning commands from the CNC control with a pitch of 0.001 mm (1 nm) to the axis servo motors, which are equipped with ultra-high resolution 16 million pulse coder feeds, any accumulation of axial movement errors are eliminated by giving a very precise and smoother feed to further enhance the machining accuracy.

When these new developments are combined with well-proven functions such as high speed non- electrolysis AC cutting and the latest Al active corner control that pre-empts a change in either the roughing or finishing cutting path and removes any slack from the wire feed, precise corner control can be achieved without having to modify the programmed cutting path. A micro finish power supply option also enables fine surface finishes as high as 0.7 µm to be achieved.

The ultra-high speed AWF system thermally melts the wire which dramatically simplifies the wire cutting mechanism design reducing service demands and extending the reliability of the machine. According to the 600 Group the annealing effect of the heat generated in the wire improves its straightness and creates a very sharp edge at the point of cut. It is also stated that with the thermal melting system, wire disconnection takes just 4s and wire reconnection 8 s, while the sharp edge created helps automatic insertion of the wire in the wire guide and eliminates any need for a split guide. As an option, this system can be applied to finer wire diameters between 0.05 and 0.07 mm.

Wire threading can also be performed while submerged on workpieces up to 100 mm thick which eliminates time to drain and refill the tank and hence improves the productivity of the process.

As a further addition, to help in applications involving unmanned wire cutting, when the process start hole is very small or the hole is not in the correct position, the control system software will automatically search for a position where connection can be made, and, if a short-circuit occurs after connection, it will automatically carry out a search for a short-circuit released position. Should the automatic reconnection of wire be required, it can be performed on, or very close to the breakage point in the profiled cutting groove without having to return to the start position.

The Fanuc Alpha-O/C has a maximum workpiece capacity of 650 mm × 450 mm × 180 mm with table travel of 320 mm × 220 mm while the Alpha-l/C will accommodate parts up to 830 mm × 730 mm × 300 mm as standard. As an option, this can be increased to 1;000 mm × 730 mm × 300 mm: Table travel is 550 mm × 370 mm.

The U and V-axis that travels on both machines is ± 60 mm × ± 60 mm and maximum standard taper angle is ± 30° over 80 mm. As an option, this can be increased to ± 45° over 40 mm. Wire size as standard is 0.1-0.3 mm with option of 0.05-0.3 mm diameter. Maximum wire capacity is 16 kg however, an optional 20 kg supply can be provided.

Details available from: 600 Centre. Tel: 01509600600; E-mail: cnctools@600centre.co.uk; Web site: www.600centre.co.uk