As reported previously here at IMT Machining Journal, GF AgieCharmilles will be showing its machinery at TECMA 2013 in Mexico City. Among that machinery will be a 5-axis machining system that has been designed as much for accuracy, advanced alloys, and short production runs as for large part volumes and conventional metals.
The high-performance Mikron HPM 450U has a number of features that optimize machining and productivity, says Gisbert Ledvon, director of business development at the Lincolnshire, Ill., company.
Among these is a direct-drive rotary/tilt table that allows tools to operate at maximum torque and cutting speeds. Ledvon says this is because the table axes move at the same speed as the cutting-tool axes. The table rotates 360 deg at up to 140 rpm, and has a tilt angle of -120/45 deg. These capabilities help assure precision cutting, good surface finish and longer tool life, especially when removing materials such as high-strength alloy. The table also improves the machining of 3-D parts — all five axes can operate simultaneously — and helps maintain a constant chip load.
Ledvon says that with the rotary/tilt table there is no need for second or third operations after machining to finish a part. This is a benefit for low-run parts, such as in aerospace, where production volumes can be as low as 50 to 100 pieces and customers want orders on a just-in-time basis and at low cost.
AgieCharmilles has installed the rotary/tilt table on other high-speed machining systems, but this is the first time it is on the HPM series machines.
Another feature of the machining system is a “smart” control that monitors vibration and heat expansion in the spindle. The machine’s frame is made of polymer granite, a material that dampens vibrations and is, Ledvon says, 10 times less susceptible to heat expansion than conventional cast iron frames. However, because the spindle is metal, cutting deviation caused by heat expansion is a concern. Thus, when the smart control detects thermal expansion in the spindle, Ledvon says the control compensates by making minor adjustments — 1 to 5 microns, for example — to the X, Y, Z and B axes to maintain cutting precision.
The HPM 450U has a compact footprint. This is due in part to the polymer granite, which permits an internal tool-changing magazine (60 tools) to be integrated within the machine, Ledvon explains. Normally, this would add about 1.5 m (4.9 ft) to the side of the unit. An external circular magazine is also available, with a capacity for 220 tools. If an automated pallet changer were to be installed, it would add 3 sq m (32.3 sq ft) to the footprint, he estimates.
The machine has a large work envelope. The maximum X- and Y-axis traverse paths are 600 and 437 mm (23.6 and 17.2 in, respectively), while the Z axis has a 450-mm (17.7-in) clearance between the table surface and spindle nose.
Two spindle options are available: 12,000 and 20,000 rpm. The lower-speed option has an ISO 40 taper for conventional tools, and the high-speed version has an HSK-A63 taper for machining diverse metals. Both have vector control for maximum torque at low speeds, a ceramic hybrid spindle bearing, and spindle casing cooling with controlled internal coolant.
Ledvon says the Mikron HPM 450U replaces the UCP600 Vario machining system, which is no longer being produced.