Precise 5-axis VMC has high stable axis traverse
Modified gantry design on a 5-axis vertical machining centre positions all guideways above the working area and Y-axis has a patented arrangement of three staggered guideways to give stable traverse
On display from Hermle, during the recent 50th Anniversary open day held by UK distributor, Geo Kingsbury Machine Tools, were three 5-axis, vertical-spindle machining centres (VMC). Each VMC has an integral, swivelling trunnion supporting a rotary table. The largest machine in the manufacturer’s C-Series, designated C 50 U, was demonstrated for the first time in the UK.
Capable of single-digit micron accuracy, its working envelope is two and a half times bigger than that of the next largest model in the range (C 40 U), extending the size of component that can be machined to 1000 x 1100 x 700mm.
Despite its large capacity and integral magazine that allows SK 40 / HSK A 63 or SK 50 / HSK A 100 tools to be picked up directly by the spindle, the machine occupies only 3 x 6.5 x 3.5m of space on the shop floor.
Production potential is high owing to 6m/s2 acceleration to traverse rates of 60m/min in the X- and Y-axis, 55m/min in Z, even though components can weigh up to two tonnes.
The modified gantry design positions all guideways above the working area.
The Y-axis has a tandem drive for high machine dynamics and features a patented arrangement of three staggered guideways, one mid way between and set back from the outer two.
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This halves the Y-axis span and gives stable traverse using three-point support.
Control options are Heidenhain iTNC 530 or Siemens Sinumeric 840 D, both enabled for modern Cube 67 / Profibus digital communication and networking.
Hermle offers multiple automation options for ‘lights-out’ running based on pallet change, transport and storage that either serves one machine, or can be extended to configure a flexible manufacturing system.
Likewise, there are robotic options for loading, handling and unloading components.
To give an idea of the machine builder’s capabilities in this area, the smallest C 20 U 5-axis machine was equipped with a PW 160 automatic handling and storage system for up to seven pallets of 500mm diameter or 400 x 400mm.
Capable of being factory-fitted or retrofitted, the system brings automation to the mould shop and complex component manufacturing environment, as pallets may be exchanged to and from the trunnion-mounted rotary table that provides fourth and fifth CNC axes in Hermle C-Series machines.
In its simplest form, the PW 160 handles three pallets using a rotating 2APC (twin automatic pallet changer) fitted with double grippers at each end.
It travels in the Y-axis direction, sharing its time between the machining area and a fixturing station at the front of the machine.
The design allows a component fixtured on a pallet to be introduced to the working area and production to start while the next component is still being set up, minimising idle time.
Additional flexibility can be obtained by increasing storage within the system to seven pallets.
An optional, four-pallet storage carousel is positioned to the side of the 2APC unit, exchange being effected by 180-deg rotation parallel to the X-axis.
Pallets with finished components and/or those awaiting machining may be parked in the carousel.
Pallet management software is built into the machine control, either a Heidenhain iTNC 530 or a Siemens S 840D, both of which are Ethernet enabled for networking.
Constructed on a mineral casting that provides stability for rapid, accurate pallet exchange, the PW 160 is easy to install, as it is a single-lift unit that does not need special foundations.
The footprint of the pallet changer is compact at 2.5m2 while that of the additional four-pallet store is only 1.0m2, so a full seven-pallet storage and handling system consumes only 3.5m2 of factory space in front of a machine.
Although the PW 160 is intended to facilitate automated running of a machining centre, the operator can nevertheless gain access to the working area from the side for manual intervention if necessary.
