Heavy-Duty VMC Provides High-Accuracy Positioning

The Johnford SV-60H vertical machining center, available from Absolute Machine Tools, is designed for durability, rigidity and capacity combined with speed.

The Johnford SV-60H vertical machining center, available from Absolute Machine Tools, is designed for durability, rigidity and capacity combined with speed. Available in #50- and #40-taper versions, the VMC performs heavy cutting in a large work envelope, providing X-, Y- and Z-axis travels measuring 60", 28" and 25", respectively. A two-speed gearbox spindle and boxway construction enable heavy cuts.

The VMC’s C frame is made from heavily ribbed Meehanite FC-30 cast iron, said to eliminate vibration while promoting good surface finishes and long cutting tool life. Four oversized boxways in the Y axis support the machine’s saddle and worktable, delivering high X-axis accuracy over the full travel range of the machine. All sliding surface areas and gibs are coated with Turcite-B and hand-scraped for precise fit and alignment.

The placement of the motor and gearbox ensures no offset and, along with the hydraulic counterbalance system, promotes steady, smooth movement of the headstock along the Z axis. This design significantly reduces torsion on the headstock and ensures optimum rigidity, long-term accuracy and repeatability, the company says. Large-diameter, pre-tensioned ballscrews have a double-nut preloaded design, reducing the potential for thermal growth and promoting high accuracy and high-speed positioning.

The machine has a 3.35" (85-mm) spindle shaft employing seven bearings for high stiffness and cutting stability. Class-7 steel bearings enable standard spindle speeds ranging to 6,000 rpm. For applications requiring high torque at low rpms, a standard two-speed gearbox head gives full power at only 375 rpm. When higher rpms are required, a 35-hp, 10,000-rpm direct-drive spindle or a 56-hp, 15,000-rpm integral spindle with HSK-100A interface as an option.

Additional features include a FANUC OiM-D control with Manual Guide I Conversational, a full enclosure, chip conveyors, a spindle chiller and a high-speed automatic toolchanger.