Multiple Processes in Single Setup

MIAMISBURG, OH — United Grinding Technologies, Inc. (UGT) announces the 6-axis CNC ewamatic line, a new addition to the Ewag line of high-precision tool grinding centers specifically designed for tough-to-grind tungsten carbide, polycrystalline diamond (PCD) and polycrystalline boron nitride (PCBN) tools, indexable inserts and rotary tooling. The ewamatic combines in a single machine multiple processes often required to address these difficult materials. Chris Stine, VP / National Sales Manager, explains that grinding tungsten carbide, PCD and PCBN has long been fraught with difficulty — dulling of the diamond grinding wheel, reduced grind times, constant wheel surface regeneration and uncertain stock removal rates. “More often than not,” he says, “precision tools of these materials are manufactured in two or more stages — a material removal process, such as EDM, followed by finish grinding.  This conventional method, however, has its own problems, the major one being a degradation of tolerances due to multiple chucking from one machine to another.  The ewamatic line approach combines both processes — spark erosion and grinding — in a single machine, in a single setup.” General SpecsX-axis travel is 360 mm, Y-axis travel is 240 mm and Z-axis infeed is 220 mm.  X-, Y- and Z-axis resolution is 0.0001 mm, with a feed rate of 10 m/min. Infinitely variable swiveling B-axis travel is  ±120°, with a resolution 0.0001° and a feed rate of 6,500°/min. Inclining A-axis travel (single-spindle grinding head or turret grinding head) is -10° to +23°, with a resolution of 0.0001° and a feed rate of 1,500°/min. C-axis resolution (dividing head with or without cylindrical grinding, or workhead with side clamping for periphery grinding) is of 0.0001°, with a feed rate of 6,000°/min .The 4 kW AC variable speed motor achieves 8,000 RPM (7.5 kW, 12,000 RPM). FeaturesModular by design, the ewamatic can be tailored to address a wide range of individual product applications. “The ewamatic excels at ultra-precise grinding of highly complex tools, screws, inserts and other parts, many common to the medical/dental industries,” Barber says.  “Bone screws, reamers, hip and joint replacement parts, as well as the equally complex tools needed to produce them are areas of growing interest.” Step reamers, drills or milling cutters, as well as circular and angular PCD or PCBN indexable inserts, can be ground efficiently to extraordinarily tight tolerances.  Convex radii and tangents with equal or unequal clearance angles are also handled routinely.  The versatility of the ewamatic is facilitated by the star-shaped turret grinding head which features up to six independent grinding spindles (max. 12 grinding wheels) to accommodate rotary applications from 0.1 mm to 35 mm in diameter. Changing a single work head permits grinding of periphery, cutting angles and edge chamfers, or spark erosion followed by finish grinding complex cylindrical or conical tools with straight or spiral teeth from tungsten and other tough materials. Multiple process operations are accomplished in a single clamping.  3D measuringCalculating stock removal in grinding PCD/PCBN is, quite simply, impossible. The considerable wear on the grinding wheel face, as well as the unknown stock removal of the tool being ground, requires an in-process measuring system to check effective stock removal.  On the ewamatic, an automatic swiveling 3D measuring probe inspects the cutting edge of the tool to be ground and automatically transmits compensation data relative to the infeed rate. The measuring cycle repeats itself several times during grinding, depending on the workpiece, and follows the “measure-grind-measure” principle until the required tolerances are achieved. ControlThe NUM 1050 is a highly flexible, robust and user-friendly CNC control. Setup and changeover are fast and uncomplicated due to user-friendly Windows™-based Numroto-Plus software permitting conversational or real-time programming of standard or special tools.  Integrated data management system allows storage of all grinding features, parameters, cycles and routines and allows simultaneous programming of different batches with different geometries. Remote diagnostics, process control and trouble-shooting via standard telephone line and machine modem link are easily facilitated A standard simulation program displays the grinding wheel during the grinding process in relation to the calculated grinding path.  This powerful tool permits process analysis and verification prior to actual grinding, assuring that the simulated process matches the desired finish ground result. The ewamatic line is also designed for production as a fully automated cell, including automatic loading and unloading by means of a Scara 4-axis robot (with or without machine vision for part handling), part sorting, multiple pallets and pallet stacking and an ultrasonic cleaning station.