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KL-TECH s.r.o | www.klte.cz Cutting Data Diameter / Depth Chart and Speed / Feed Rate Calculation of NC Spot Drill Sectional view of Chamfering (for a = 90° only) Į d t Minimum 1 mm (0.04”) Sectional view of Spotting & Engraving Į d t Minimum 1 mm (0.04”) NC40 / NC60 Į d t Other grade Depth of Spotting ”t” Instruction of Use >> 1. From Spot diameter “d” to get drill depth “ t ”. 3RLQWDQJOH³Į´LVGHWHUPLQHGE\ZKLFKWRROKROGHU\RXXVH )URP³G´GUDZDKRUL]RQWDOOLQHWRJHWLQWHUVHFWLRQRIWKHOLQHE\SRLQWDQJOH³Į´ 4. From the intersection draw a vertical line to the bottom to have depth of spotting “ t ”. “ t ” is the drill depth of the NC program. 5. The sectional view of spotting will depend on the shape of insert, NC40 and other grades of inserts have different sectional view. 6. For chamfering, do not use tip of insert, 1mm(0.04”) minimum clearance is required for a smooth surface finish. Calculate spindle speed and feed rate >> 1. Using your “d” value and cutting speed Vc from the data sheet, calculate spindle speed “S”(RPM). 2. “ F” feed rate per minute F = f x S = RPM x IPR Metric Inch d = diameter-inch d = diameter -mm Vc X 1000 S = X d S = Spindle Speed -r.p.m. S = (3.82xSFM) Vc = Cutting Speed -m/min. F = S x f F = fxS d S = Spindle Speed-r.p.m. Speed-ft./min. SFM = Surface Vc (m/min.) x 3.28 f = mm/rev. f = IPR = inch/rev. F = mm/min. F = inch/min. 32 Nine9 Cutting Tool & Tool Holders