Not long ago, five-axis set-ups represented a baseline in CNC machine flexibility and functional versatility. Now, manufacturers and machine shops have pushed their own capabilities — and their expectations of CNC machines — beyond the limits of five-axis designs.
Machine builders are responding. Recently, Schütte introduced its 325linear machine, a five-axis CNC grinder with extended X- and Y-axis movement, plus two auxiliary slides for workpiece clamping and improved grinding wheel guidance over the entire machining envelope. Micro tools, gun drills, hob cutters, and complex geometries can be accommodated on this machine, which typically operates in the range of 2,500-4,000 rpm.
The additional second auxiliary slide enables the 325linear to use tool guidance, part support, tailstock or workpiece pallets in operation. In addition to more set-up options, the machine expands the users’ automation opportunities with advances in wheel change and robotic workpiece handling.
Specifically, on the A-axis, a user can install collet chucks, hydraulic expansion chucks or multi-range chucks. With the automated collet changer on the machine, workpieces with different diameters can be clamped with high concentricity in the unmanned loader station. The Schütte A-axis configuration on the 325linear also permits position-oriented clamping of non-rotationally symmetrical workpieces. In this way, sequential workpieces with various roughing and finishing requirements can be preset on the machine for continuous processing.
Likewise, the Schütte grinding system offers scalable automation, with a 140-position tool changer, 5-24 grinding wheel magazine, and a flexible robotic tool gripper for changing the smallest micro tools.
The same base machine can be used for continuous production of a single part in a work cell set-up, or for sequential one-off work, as needed.
The 325linear features a universal rotation A-axis with a high level of concentricity (<0.0001º resolution) and pitch accuracy, while the XYZ-axis resolution is maintained at <0.1 microns.
The swiveling C-axis for the grinding head has a 225º range of motion, also with <0.0001º resolution accuracy. The primary motor spindle operates up to 12,000 rpm with 15kW max. drive output, while the grinding spindle option affords a max. speed of 24,000 rpm. Linear axis travel on the machine is (XYZ) 480 mm x 250 mm x 275 mm.
The 325linear machine is supplied with SIGSpro (Schütte Integrated Grinding Software) as the proprietary control interface, so users and programmers can assign clamping options for each grinding operation being performed. When the support and tool guidance system are used, pre-set distances from the grinding wheel to the workpiece can be defined and held constant. In the 3D mode, all cycle steps can be simulated, controlled and optimized for exact estimating, collision avoidance and even external workstation integration with the other workpieces.
All motion control on this new grinder is maintained on a Siemens 840D sl CNC with compatible drive technology.