GROB Horizontal Machining Center Multi-tasks Precisely

The machine tool division of GROB Systems Inc. introduces the G350 horizontal machining center that is capable of production using up to five axes, providing the ability to handle a multitude of jobs at once. The G350 features precise output, modular, cost-effective design and is long lasting in comparison to other similar systems, according to the manufacturer.

“These machines are not designed to be ‘throw away,’ where the machine has run its course after three to five years. We expect the lifetime to be well in excess of 10 years,” says Doug Schroeder, manager of process engineering and project management for GROB Systems.

The machining center’s Z-axis is particularly precise and stable with greater tool rigidity due to a slide-mounted spindle module. The spindle/slide arrangement is one of several high-strength construction elements. The spindle’s body is mounted on a slide that supplies the entire spindle drive module for the Z-axis movement; the spindle moves in the X-axis by means of a second slide instrument. The front bearing acts as a support point for the tool/spindle overhang, which is maintained by the spindle mechanism’s movement along the guideway surfaces. The G350 performs with positional tolerance precision of .01 mm (.00039 in) and a positional variation of .005 mm (.00019 in).

“The G-series machines in general were developed to be very robust and long-lasting machines while also being highly dynamic with excellent high-speed performance,” Schroeder says.

Front and side access for part loading and tool inspection is possible from the location of the spindle and table both on one side of the machine’s centerline. With this construction, program inputs and tool paths can be reviewed clearly, and the machine size is compact with a small footprint.

The machining system’s travel distances are 600 mm (23.6 in) in the X-axis, 655 mm (25.8 in) in the Y-axis and 675 mm (26.6 in) in the Z-axis. The X movements reach up to 65 m/min (2,559 in/min), Y at 36 m/min (1,417 in/min) and the Z-axis travels up to 90 m/min (3,543 in/min). The spindle drive provides tooling speeds that range from 8,000 to 18,000 rpm for optional spindle drives and up to 12,000 rpm for the standard drive. The machine’s table can be adapted for A/B-axes of tilt and rotation, or B-axis inclusion only.

The life, rigidity and precision of the G350 make the machine appropriate for high-volume production and tough metal removal environments including coolant-reliant and MQL operations. Chip fall and clearing under rigorous machining conditions are optimized by the horizontal spindle and the table’s column-mount and slide that facilitate the Y-axis movement.

The G350 has four control options—Fanuc, Siemens, Bosch Rexroth and Heidenhain— developed for operator familiarity, enterprise consistency and to meet application mandates. GROB based these options on a market study performed with worldwide job shops, in which the company determined that these four controls suppliers are the most common controllers used by GROB’s target customer base. The companies are not tied together by any sort of formal business relationship, according to Schroeder. “Control packages are all unique and typically require small changes in the way NC programs are written from one platform to the next. These companies are all ‘main stream’ and have spare parts and support for their products worldwide,” Schroeder says. “You do not have to worry about company-specific controllers (i.e. GROB-developed only) as you might with some other machining suppliers.”

The GROB G350 is 3,520 mm (139 in) long by 2,425 mm (85 in) wide by 2,680 mm (106 in) high. Turnkey automation components are available with pallet changer, pallet pools, robotic handling or gantry system for auto load/unload and unattended operation.

The horizontal machining center has a modular assembly produced at the company’s U.S. facility for short lead times.