Article From: 1/21/2009 Production Machining
Haas Automation Inc. offers a line of VMCs designed for the moldmaking, tool and die and medical industries. Called the VM Series, these VMCs provide the accuracy, rigidity and thermal stability required for high precision work, the company says. Available in three frame sizes, each machine features a 12,000-rpm spindle driven by a 30-hp vector dual-drive system, a 24-pocket side-mount toolchanger, a high-speed control with full look-ahead and a multi-fixturing table.
The smallest of the machines is the VM-2, with a 30" x 20" x 20" work cube and a 36" x 18" table. The VM-3 features a 40" x 26" x 25" work cube and a 54" x 25" table, and the VM-6 (the largest of the VM machines) has 64" x 32" x 30" travels and a 64" x 28" table. For maximum fixturing versatility, each machine’s cast-iron table features T-slots in the X and Y directions, as well as precision dowel-pin bores and a variety of drilled and tapped holes.
All VM machines feature cast-iron construction, with extensive internal ribbing to increase rigidity and dampen vibrations. High-precision linear guides on all axes are designed to increase rigidity, while offering low-friction and long-term reliability. High-speed brushless servos, fine-pitch ballscrews and high-resolution encoders ensure precise positioning and extreme repeatability, the company says.
The 40-taper spindle uses an inline direct-drive system that couples the motor directly to the spindle to reduce heat, vibration and noise. This results in smooth, quiet operation and extreme thermal stability. On-the-fly wye-delta switching provides plenty of low-end torque, as well as high rpm for high-speed machining.
To further ensure thermal stability, coolant is circulated through the head castings of VM machines to remove heat generated by the spindle. To prevent radiated heat from affecting the casting, the headstock is insulated and cool air is circulated through the entire assembly. An electronic thermal-compensation algorithm in the Haas control accurately models ballscrew heating from high-duty cycles and automatically corrects for any expansion that could cause positioning errors.
VM Series machines come standard with a 24-pocket side-mount toolchanger that swaps tools in 2.8 seconds. Also standard are an automatic chip auger, remote jog handle, programmable coolant nozzle, automatic air gun, high-speed machining software with look-ahead, hard drive with Ethernet interface, USB port, Visual Quick Code programming and expanded program memory to 16 MB.