Threading Technology – Clamping Technology 520

427 Twist Drills STEEL VA Accessories 3 x D Tech. Info v c / f Product Finder 5 x D 6 x D 8 x D 2-3.5 x D 5.13 Problems, possible causes and solutions in drilling Problems: • Excessive wear on the corners • Built-up edge • Wear on the margins Possible causes: • Excessive machining times • High temperature and/or friction • Concentricity run-out > 0.02 mm • Unstable clamping of workpiece or tool • Coolant-lubricant too dry Solutions: • Exchange twist drill in time and regrind • Increase coolant-lubricant volume • Use coolant-lubricant with higher oil content, or additives • Reduce cutting speed • Reduce feed for drilling through Problem: • Chipping on the cutting corners Possible causes: • Excessive feed • Workpiece moves when the drill breaks through • Machine is unstable • Twist drill slips due to unsatisfactory tool clamping • Concentricity run-out > 0.02 mm Solutions: • Improve workpiece clamping • Use a different clamping tool, e.g. clamping system PGR or hydraulic expansion chuck • Reduce feed Problem: • Coating coming off on the margins Possible causes: • Excessive friction • Slanted exit • Adhesive workpiece material • Reground too many times (excessive coating thickness) Solutions: • Use coolant-lubricant with higher oil content, or additives • Reduce feed for exiting • Reduce the number of times you regrind your drills