Despite weighing 23 tonnes, the machine does not need any special foundation as the polymer monobloc bed has inherent mechanical stability. The lathe offers the best deflection resistance of any comparable machine on the market, claims the company, and has good damping properties thanks to generously dimensioned linear guideways in the X and Z axes. A ratio of static masses to moving masses of greater than 5:1 not only provides high stiffness levels, but enables dynamic movements with low vibration.
Workpieces up to 1.6 m long can be machined from bar up to 102 mm in diameter, while the chuck diameter is 315 mm (optionally 400 mm). Precision is assured due to the thermal stability provided by extensive cooling circuitry throughout the machine’s structure, moving elements and peripherals. Stored energy can be used for other purposes, such as additional process steps or heating the user's factory.
The G420 features a 26 kW/12,000 rpm milling spindle moving in the X, Y, Z and B axes at the top of a vertical bed. A 58-position (optionally 115-position) magazine is supplied for HSK-T63 or Capto C6 tools.
The Z-axis slideway of the milling spindle, and the Y/B axis with hydrodynamic bearing support and linear scale feedback of quill movement, are symmetrically designed for stability. A Y-axis stroke of ±170 mm, B-axis swivel of ±115° and large X-axis travel of 750 mm, together with the Z-axis movement and C-axis on the main/counter spindles, allow up to 5-axis simultaneous machining of complex components.
There are two X/Y/Z turrets mounted on vertical guideways below the centerline, between the 34/41 kW (100%/40% DC) main spindle and identical counter spindle. The overall design ensures chip flow away from the machining area into a conveyor that can be mounted to the left or right.
Since each of the lower tool carriers is equipped with 12 live (7.5 kW/5,400 rpm) stations, more than enough tools are available for even the most demanding jobs, without the need for additional set-ups. The turrets feature a VDI 40 tool interface with W-serration, and both can be moved not only in the X and Z axes, but also ±70 mm in Y.
Both turrets are able to work at either spindle position, and if a static turning tool is mounted in the upper motor spindle, three tools can be in cut simultaneously. Alternatively, a steady can be mounted in one of the turrets to assist in machining shaft-type components with the other two tool carriers.
An integrated, 2-axis handling unit is optionally available for loading and unloading parts weighing up to 20 kg (120 mm maximum diameter). Further automation solutions, involving robotic handling and conveyor systems, can be integrated to meet specific needs.
Control is by an adapted Siemens 840D sl operated via the Industry 4.0-compatible iXpanel system from Index. Having an 18.5” touch-screen interface, the panel provides the operator with intuitive set-up and control using softkeys.
