Kern Evo

The Kern Evo is a small 5-axis machining center for micro-milling: 300 mm of X, 280 mm of Y and 250 mm of Z, an HSK 25 spindle that reaches 50,000 rpm, and a rotary-swivel table for workpieces up to 50 kg. An authorised distributor's page is the source of these figures. The control is a Heidenhain iTNC 530, where the Micro Vario and the Pyramid Nano are listed with a Heidenhain TNC 640. Anyone who programs or post-processes for several machines should take that difference into account.

Everything about the spindle points at small cutters. HSK 25 is a small interface, the top speed is 50,000 rpm and the power is 6.4KW, so stock comes off in many light passes at high feed and not in a few heavy ones. The tool limits say the same thing: 50 mm maximum diameter and 105 mm maximum length. Check long-reach tools for deep cavities against that 105 mm before a job is quoted.

The swivel axis runs from -10° to +100° and the rotary axis is 360° continuous. That reaches just past horizontal on one side, but the table hardly tips the other way, so a part that needs access from both sides of vertical has to be brought round by the rotary axis. The clamping surface is 350 x 230 mm and the workpiece size is given as 280 x 260 mm. With 280 mm of Y against 220 mm on the Micro HD, the Evo has the longer Y stroke of the two, while the Micro HD has 350 mm of X.

Three magazine sizes are listed: 32, 63 or 95 tools. Chip-to-chip time is 5.5 s, which costs little on long finishing cuts and more on parts made of many short operations. The machine weighs 3,100 kg and needs at least 2.50 x 2.80 x 2.20 m (W/D/H). It is the lightest of the range to site: the Micro Vario is listed at 5.200 kg and the Pyramid Nano at ca. 8.000 kg.