Grob G 350 T

The GROB G 350 T is listed by GROB among its mill-turn machining centers. Its B axis, the 360 degree table axis, runs at up to 1,200 rpm, so a part can be turned and milled in one clamping within 600 mm of X, 855 mm of Y and 750 mm of Z travel.

Only one spindle is listed. It has an HSK-A/T63 interface, 206 Nm of torque, 16,000 rpm and 32 kW. The G350, by comparison, starts with an 83 Nm, 12,000 rpm HSK-A63 spindle rated 52 kW. The mill-turn machine therefore comes with the high-torque spindle as its single configuration, at lower power, and tooling has to match the HSK-A/T63 interface.

For turned parts the figures to plan around are the 620 mm interference diameter, the 570 mm table and the table load: 270 kg with a pallet, 350 kg without. The G350 carries 340 kg with a pallet and 400 kg without, so the turning table costs some capacity. A part spinning at up to 1,200 rpm must also be balanced and clamped for that speed. The table says nothing about permitted speed against part weight, which is a question to put to GROB with the actual part.

The rest of the machine is quick. Rapid traverse is 70/45/90 m/min in X/Y/Z, chip-to-chip time is 2.7 s (t1, according to VDI 2852) and positioning accuracy is 0.006 mm in X, Y and Z. The A axis swivels 230 degrees. Tool length is 365 mm with the single disk-type magazine and 365/180/550 mm (bottom/top/over both disks) with the double one. Weight is 15,500 kg, and the control is SIEMENS 840D sl or HEIDENHAIN TNC 640 with GROB4Pilot.