C007E SPECIFICATION, FUNCTION OF TOOL FEATURES,TROUBLE SHOOTING, FORMULAE
TROUBLE SHOOTING FOR TURNING... N002 CHIP CONTROL FOR TURNING... N004 EFFECTS OF CUTTING CONDITIONS FOR TURNING... N005 FUNCTION OF TOOL FEATURES FOR TURNING... N007 FORMULAE FOR CUTTING POWER... N011 TROUBLE SHOOTING FOR FACE MILLING... N012 FUNCTION OF TOOL FEATURES FOR FACE MILLING... N013 FORMULAE FOR FACE MILLING... N016 TROUBLE SHOOTING FOR END MILLING... N018 END MILL FEATURES AND SPECIFICATION... N019 PITCH SELECTION OF PICK FEED... N021 TROUBLE SHOOTING FOR DRILLING... N022 DRILL WEAR AND CUTTING EDGE DAMAGE... N023 DRILL FEATURES AND SPECIFICATION... N024 FORMULAE FOR DRILLING... N027 METALLIC MATERIALS CROSS REFERENCE LIST... N028 SURFACE ROUGHNESS... N032 HARDNESS COMPARISON TABLE... N033 FIT TOLERANCE TABLE (HOLE)... N034 FIT TOLERANCE TABLE (SHAFT)... N036 DRILL DIAMETERS FOR TAPPING... N038 HEXAGON SOCKET HEAD BOLT HOLE SIZE... N039 INTERNATIONAL SYSTEM OF UNITS... N040 TOOL WEAR AND DAMAGE... N041 CUTTING TOOL MATERIALS... N042 GRADE CHAIN... N043 GRADES COMPARISON TABLE... N044 INSERT CHIP BREAKER COMPARISON TABLE... N050 N001
TROUBLE SHOOTING FOR TURNING Solution Insert Grde Selection Cutting Conditions Style nd Design of the Tool Mchine, Instlltion of Tool Trouble Fctors Select hrder grde Select tougher grde Select grde with better therml shock resistnce Select grde with better dhesion resistnce Cutting speed Feed Up Down Depth of cut Coolnt Do not use wtersoluble cutting fluid Determine dry or wet cutting Select chip breker Rke Corner rdius Led ngle Up Down Honing strengthens the cutting edge Clss of insert (Unground Ground) Improve tool holder rigidity Increse clmping rigidity of the tool nd workpiece Decrese holder overhng Decrese power nd mchine bcklsh tool grde Insert wer quickly generted cutting edge geometry Deteriortion of Tool Life Chipping or frcturing of cutting edge cutting speed tool grde cutting conditions Lck of cutting edge strength. Therml crck occurs Wet Dry Build-up edge occurs Wet Lck of rigidity Out of Tolernce Deteriortion of Surfce Finish Dimensions re not constnt Necessry to djust often becuse of over-size Poor finished surfce Poor insert ccurcy Lrge cutting resistnce nd cutting edge flnk tool grde cutting conditions Welding occurs cutting edge geometry Chttering Wet Genertion of Het Workpiece over heting cn cuse poor ccurcy nd short life of insert cutting conditions cutting edge geometry N002
Solution Insert Grde Selection Cutting Conditions Style nd Design of the Tool Mchine, Instlltion of Tool Trouble Fctors Select hrder grde Select tougher grde Select grde with better therml shock resistnce Select grde with better dhesion resistnce Cutting speed Feed Up Down Depth of cut Coolnt Do not use wtersoluble cutting fluid Determine dry or wet cutting Select chip breker Rke Corner rdius Led ngle Up Down Honing strengthens the cutting edge Clss of insert (Unground Ground) Improve tool holder rigidity Increse clmping rigidity of the tool nd workpiece Decrese holder overhng Decrese power nd mchine bcklsh Notch wer Burrs (steel, luminium) cutting conditions Wet cutting edge geometry Burrs, Chipping etc. Workpiece chipping (cst iron) cutting conditions cutting edge geometry Vibrtion occurs tool grde Burrs (mild steel) cutting conditions cutting edge geometry Wet Vibrtion occurs cutting conditions Wet Poor Chip Dispersl long chips Chips re short nd scttered Lrge chip control rnge cutting edge geometry cutting conditions Smll chip control rnge Dry cutting edge geometry N003
CHIP CONTROL FOR TURNING ychip BREAKING CONDITIONS IN STEEL TURNING Type A Type B Type C Type D Type E Type Smll Depth of Cut d < 7mm Lrge Depth of Cut d=7 15mm Curl Length l No curl l > 50mm l < 50mm 1 5 Curl i 1 Curl Less Thn 1 Curl Hlf Curl Note Irregulr continuous shpe Tngle round tool nd workpiece Regulr continuous shpe Long chips Good Good Chip scttering Chttering Poor finished surfce Mximum Cutting speed nd chip control rnge of chip breker In generl, when cutting speed increses, the chip control rnge tends to become nrrower. 0.6 vc=50m/min 0.6 vc=100m/min 0.6 vc=150m/min 0.5 E 0.5 E 0.5 E Feed (mm/rev) 0.4 B 0.3 0.2 C D Feed (mm/rev) 0.4 B 0.3 0.2 C D Feed (mm/rev) 0.4 B 0.3 0.2 C D 0.1 A 0.1 A 0.1 A 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 Depth of Cut (mm) Depth of Cut (mm) Depth of Cut (mm) Workpiece : DIN Ck45(180HB) Tool : MTJNR2525M16N Insert : TNMG160408 Dry Cutting Grde : P10Cemented Crbide Effects of coolnt on the chip control rnge of chip breker If the cutting speed is the sme, the rnge of chip control differs ccording to whether coolnt is used or not. Feed (mm/rev) 0.6 0.5 0.4 0.3 0.2 Coolnt : Dry B D C E Feed (mm/rev) 0.6 0.5 0.4 0.3 0.2 Coolnt : Wet (Emulsion) B C D E 0.1 A 0.1 A 1 2 3 4 5 6 Depth of Cut (mm) 1 2 3 4 5 6 Depth of Cut (mm) Workpiece : DIN Ck45 Cutting Conditions : vc=100m/min N004
EFFECTS OF CUTTING CONDITIONS FOR TURNING yeffects OF CUTTING CONDITIONS Idel conditions for cutting re short cutting time, long tool life, nd high cutting ccurcy. In order to obtin these conditions, selection of efficient cutting conditions nd tools, bsed on work mteril, hrdness, shpe nd mchine cpbility is necessry. ycutting SPEED Cutting speed effects tool life gretly. Incresing cutting speed increses cutting temperture nd results in shortening tool life. Cutting speed vries depending on the type nd hrdness of the work mteril. Selecting tool grde suitble for the cutting speed is necessry. Cutting Speed (m/min) 500 400 300 200 AP25N NX2525 UE6105 MC6025 MP3025 VP15TF MC6015 NX3035 MC6035 Workpiece : DIN Ck45 180HB Tool Life Stndrd : VB = 0.3mm Depth of Cut : 1.5mm Feed : 0.3mm/rev Holder : PCLNR2525M12 Insert : CNMG120408 Dry Cutting 100 10 20 30 40 50 60 70 80 90 100 Tool Life (min) P Clss Grde Tool Life Cutting Speed (m/min) 500 400 300 200 150 100 80 MC7025 US735 MP7035 UTi20T MC7015 US7020 Workpiece : DIN X5CrNi189 200HB Tool Life Stndrd : VB = 0.3mm Depth of Cut : 1.5mm Feed : 0.3mm/rev Holder : PCLNR2525M12 Insert : CNMG120408-MA Dry Cutting 60 10 20 30 40 60 100 Tool Life (min) M Clss Grde Tool Life Cutting Speed (m/min) 500 400 300 200 150 100 80 60 MC5015 UE6110 AP25N UTi20T MC5005 UC5115 NX2525 UC5105 HTi10 Workpiece : DIN GG30 180HB Tool Life Stndrd : VB = 0.3mm Depth of Cut : 1.5mm Feed : 0.3mm/rev Holder : PCLNR2525M12 Insert : CNMG120408 Dry Cutting 10 20 30 40 60 100 Tool Life (min) K Clss Grde Tool Life Effects of Cutting Speed 1. Incresing cutting speed by 20% decreses tool life by 50%. Incresing cutting speed by 50% decreses tool life by 80%. 2. Cutting t low cutting speed (20 40m/min) tends to cuse chttering. Thus, tool life is shortened. N005
EFFECTS OF CUTTING CONDITIONS FOR TURNING yfeed When cutting with generl holder, feed is the distnce holder moves per workpiece revolution. In milling, feed is the distnce mchine tble moves per cutter revolution divided by number of inserts. Thus, it is indicted s feed per tooth. Feed rte reltes to finished surfce roughness. Effects of Feed 1. Decresing feed rte results in flnk wer nd shortens tool life. 2. Incresing feed rte increses cutting temperture nd flnk wer. However, effects on the tool life is miniml compred to cutting speed. 3. Incresing feed rte improves mchining efficiency. Flnk Wer (mm) 0.4 0.3 0.2 0.1 0 0.03 0.06 0.08 0.1 0.2 0.3 0.6 Feed (mm/rev) Cutting Conditions Workpiece : Alloy steel Grde : STi10T Tool Shpe : 0-0-5-5-35-35-0.3mm Depth of Cut p=1.0mm Cutting Speed vc=200m/min Cutting Time Tc=10min Feed nd Flnk Wer Reltionship in Steel Turning ydepth OF CUT Depth of cut is determined ccording to the required stock removl, shpe of workpiece, power nd rigidity of the mchine nd tool rigidity. 0.4 Effects of Depth of Cut 1. Chnging depth of cut doesn't effect tool life gretly. 2. Smll depths of cut result in friction when cutting the hrdened lyer of workpiece. Thus tool life is shortened. 0.3 0.2 0.1 3. When cutting uncut surfces or cst iron surfces, the 0 0.03 0.05 0.1 0.2 0.5 1.0 2.0 3.0 depth of cut needs to be incresed s much s the Depth of Cut (mm) mchine power llows in order to void cutting the Cutting Conditions Workpiece : Alloy steel Grde : STi10T Tool Shpe : 0-0-5-5-35-35-0.3mm impure hrd lyer with the tip of cutting edge nd Feed f=0.20mm/rev Cutting Speed vc=200m/min therefore prevent chipping nd bnorml wer. Cutting Time Tc=10min Depth of Cut nd Flnk Wer Reltionship in Steel Turning Flnk Wer (mm) Uncut Surfce Depth of Cut Roughing of Surfce Lyer tht Includes Uncut Surfce N006
FUNCTION OF TOOL FEATURES FOR TURNING yrake ANGLE Rke ngle is the cutting edge ngle tht hs lrge effect on cutting resistnce, chip disposl, cutting temperture nd tool life. Positive Rke Angle (+) Negtive Rke Angle (-) Positive Insert Chip Disposl nd Rke Angle Negtive Insert Tool Life (min) 200 100 80 50 30 20 10 Rke Angle 6 Tool Life Stndrd VB = 0.4 mm Rke Angle 15 6 50 100 200 Cutting Speed (m/min) Cutting Speed (m/min) Verticl Force (N) Cutting Temperture ( C) 140 120 100 1400 1200 1000 600 500 Tool Life Stndrd : VB = 0.4mm Depth of Cut : 1mm Feed = 0.32mm/rev Rke Angle -10 Cutting Resistnce Cutting Conditions Grde : STi10 Depth of Cut : 1mm Feed : 0.32mm/rev Workpiece : Alloy steel Rke Angle nd Tool Life Verticl Force Depth of Cut : 2mm Feed : 0.2mm/rev Cutting Speed : 100m/min Depth of Cut : 2mm Feed : 0.2mm/rev Cutting Speed : 100m/min Rke Fce Men Temperture -15-10 -5 0 5 10 15 20 25 Rke Angle ( ) Cutting Conditions Workpiece : Alloy steel Grde : STi10T Tool Shpe : 0-Vr-5-5-20-20-0.5mm Dry Cutting Effects of Rke Angle on Cutting Speed, Verticl Force, nd Cutting Temperture Effects of Rke Angle 1. Incresing rke ngle in the positive (+) direction improves shrpness. 2. Incresing rke ngle by 1 in the positive (+) direction decreses cutting power by bout 1%. 3. Incresing rke ngle in the positive (+) direction lowers cutting edge strength nd in the negtive (-) direction increses cutting resistnce. When to Increse Rke Angle in the Negtive (-) Direction Hrd workpiece. When cutting edge strength is required such s in interrupted cutting nd uncut surfce cutting. When to Increse Rke Angle in the Positive (+) Direction Soft workpiece. Workpiece is esily mchined. When the workpiece or the mchine hve poor rigidity. yflank ANGLE Flnk ngle prevents friction between the flnk fce nd workpiece resulting in smooth feed. Wer Depth Lrge Flnk Wer D.O.C. (Sme) Wer Depth Smll Flnk Wer % % Smll Flnk Angle Lrge Flnk Angle D.O.C. (Sme) Flnk ngle cretes spce between tool nd workpiece. Flnk ngle reltes to flnk wer. Flnk Wer (mm) 0.3 0.2 0.1 0.05 Cutting Conditions vc = 200 vc = 100 vc = 50 Frcture Rke Angle 6 $ Flnk Angle $ 3 6 8 10 12 15 20 Flnk Angle ($) Workpiece : Alloy steel (200HB) Grde : STi20 Tool Shpe : 0-6-$-$-20-20-0.5mm Depth of Cut : 1mm Feed : 0.32mm/rev Cutting Time : 20min Flnk Angle nd Flnk Wer Reltionship Effects of Flnk Angle 1. Incresing flnk ngle decreses flnk wer occurrence. 2. Incresing flnk ngle lowers cutting edge strength. When to Decrese Flnk Angle Hrd workpieces. When cutting edge strength is required. When to Increse Flnk Angle Soft workpieces. Workpieces suffer esily from work hrdening. N007
FUNCTION OF TOOL FEATURES FOR TURNING yside CUTTING EDGE ANGLE (LEAD ANGLE) Side cutting edge ngle nd corner ngle lower impct lod nd effect feed force, bck force, nd chip thickness. B h f = Sme f = Sme f = Sme 1.04B 0.97h 0.87h kr = 0 kr = 15 kr = 30 Side Cutting Edge Angle nd Chip Thickness Effects of Side Cutting Edge Angle (Led Angle) 1. At the sme feed rte, incresing the side cutting edge ngle increses the chip contct length nd decreses chip thickness. As result, the cutting force is dispersed on longer cutting edge nd tool life is prolonged. (Refer to the chrt.) 2. Incresing the side cutting edge ngle increses force '. Thus, thin, long workpieces cn suffer from bending. 3. Incresing the side cutting edge ngle decreses chip control. 4. Incresing the side cutting edge ngle decreses the chip thickness nd increses chip width. Thus, breking the chips is difficult. 1.15B B : Chip Width f : Feed h : Chip Thickness kr : Side Cutting Edge Angle Tool Life (min) 80 60 40 30 20 10 8 6 5 4 3 Workpiece : Alloy steel Grde : STi120 Depth of Cut : 3mm Feed : 0.2mm/rev Dry Cutting Side Cutting Edge Angle 15 Side Cutting Edge Angle 0 100 150 200 300 Cutting Speed (m/min) Side Cutting Edge nd Tool Life When to Decrese Led Angle Finishing with smll depth of cut. Thin, long workpieces. When the mchine hs poor rigidity. When to Increse Led Angle Hrd workpieces which produce high cutting temperture. When roughing lrge dimeter workpiece. When the mchine hs high rigidity. A Receive force A. A ' Force A is divided into nd '. yend CUTTING EDGE ANGLE The end cutting edge ngle voids interference between the mchined surfce nd the tool (end cutting edge). Usully 5 15. Effects of End Cutting Edge Angle 1. Decresing the end cutting edge ngle increses cutting edge strength, but it lso increses cutting edge temperture. 2. Decresing the end cutting edge ngle increses the bck force nd cn result in chttering nd vibrtion while mchining. 3. Smll end cutting edge ngle for roughing nd lrge ngle in finishing re recommended. ycutting EDGE INCLINATION Cutting edge inclintion indictes inclintion of the rke fce. When hevy cutting, the cutting edge receives n extremely lrge shock t the beginning of cutting. Cutting edge inclintion keeps the cutting edge from receiving this shock nd prevents frcturing. 3 5 in turning nd 10 15 in milling re recommended. Effects of Cutting Edge Inclintion 1. Negtive (-) cutting edge inclintion disposes chips in the workpiece direction, nd positive (+) disposes chips in the opposite direction. 2. Negtive (-) cutting edge inclintion increses cutting edge strength, but it lso increses bck force of cutting resistnce. Thus, chttering esily occurs. Bck Relief Angle ( ) Cutting Edge Inclintion Min Cutting Edge Side Cutting Edge Angle End Cutting Edge Angle Side Flnk Angle True Rke Angle End Cutting Edge Angle Corner Rdius N008
yhoning AND LAND Honing nd lnd re cutting edge shpes tht mintin cutting edge strength. Honing cn be round or chmfer type. The optiml honing width is pproximtely 1/2 of the feed. Lnd is the nrrow flt re on the rke or flnk fce. Honing Width Honing Width Lnd Width EDR Honing Angle Round Honing Chmfer Honing Flt Lnd Tool Life (Number of Impcts) 5000 1000 500 100 R Honing C Honing 0 0.02 0.05 0.1 0.2 0.5 Honing Size (mm) Workpiece : Alloy steel (280HB) Grde : P10 Cutting Conditions : vc=200m/min p=1.5mm f=0.335mm/rev Honing Size nd Tool Life Due to Frcturing Tool Life (min) 100 50 20 10 R Honing C Honing VB KT 5 0 0.02 0.05 0.1 0.2 0.5 Honing Size (mm) Workpiece : Alloy steel (220HB) Grde : P10 Cutting Conditions : vc=160m/min p=1.5mm f=0.45mm/rev Honing Size nd Tool Life Due to Wer Principl Force (N) Feed Force (N) Bck Force (N) 1700 1600 1500 1400 1400 900 800 700 600 800 700 600 500 R Honing C Honing 400 0 0.02 0.05 0.1 0.2 0.5 Honing Size (mm) Workpiece : Alloy steel (220HB) Grde : P10 Cutting Conditions : vc=100m/min p=1.5mm f=0.425mm/rev Honing Size nd Cutting Resistnce Effects of Honing 1. Enlrging the honing increses cutting edge strength, tool life nd reduces frcturing. 2. Enlrging the honing increses flnk wer occurrence nd shortens tool life. Honing size doesn't ffect rke wer. 3. Enlrging the honing increses cutting resistnce nd chttering. When to Decrese Honing Size When finishing with smll depth of cut nd smll feed. Soft workpieces. When the workpiece nd the mchine hve poor rigidity. When to Increse Honing Size Hrd workpieces. When cutting edge strength is required for uncut surfces nd interrupted cutting. When the mchine hs high rigidity. Cemented crbide, UTi, coted dimond nd indexble cermet inserts hve round honing s stndrd lredy. N009
FUNCTION OF TOOL FEATURES FOR TURNING yradius Rdius effects the cutting edge strength nd finished surfce. In generl, corner rdius 2 3 times the feed is recommended. Depth of Cut Feed Lrge Corner Rdius Feed Theoreticl Finished Surfce Roughness Finished Surfce (!) 40 30 20 10 Feed (mm/rev) 0.075 0.106 0.150 0.212 0.300 Depth of Cut Smll Corner Rdius Theoreticl Finished Surfce Roughness Corner Rdius nd Finished Surfce 0.4 0.8 1.2 1.6 2.0 Corner Rdius (mm) Workpiece : Alloy steel (200HB) Grde : P20 Cutting Speed : vc=120m/min p=0.5mm Tool Life (Number of Impcts) 2000 1000 0.5 1.0 1.5 2.0 Corner Rdius (mm) Workpiece : Alloy steel (280HB) Grde : P10 Cutting Conditions : vc=100m/min p=2mm f=0.335mm/rev Flnk Wer Width (mm) 0.4 0.2 0 Flnk Wer Crter Wer (Crter Depth) 0.5 1.0 1.5 2.0 Corner Rdius (mm) 0.08 0.04 0 Crter Wer Depth (mm) Workpiece : Alloy steel (200HB) Grde : P10 Cutting Conditions : vc=140m/min p=2mm f=0.212mm/rev Tc=10min Corner Rdius Size nd Tool Life Due to Frcturing Corner Rdius Size nd Tool Wer Effects of Corner Rdius 1. Incresing the corner rdius improves the surfce finish. 2. Incresing the corner rdius improves cutting edge strength. 3. Incresing the corner rdius too much increses the cutting resistnce nd cuses chttering. 4. Incresing the corner rdius decreses flnk nd rke wer. 5. Incresing the corner rdius too much results in poor chip control. Corner Rdius nd Chip Control Rnge When to Decrese Corner Rdius Finishing with smll depth of cut. Thin, long workpieces. When the mchine hs poor rigidity. When to Increse Corner Rdius When cutting edge strength is required for interrupted cutting nd uncut surfce cutting. When roughing workpiece with lrge dimeter. When the mchine hs high rigidity. 0.6 1.8 Feed (mm/rev) 0.5 0.4 0.3 0.2 0.1 B C E D A : 0.4R(TNGG160404R) : 0.8R(TNGG160408R) : 1.2R(TNGG160412R) 1 2 3 4 5 Depth of Cut (mm) 0.2 R1 15 Workpiece : DIN Ck45 (180HB) Insert : TNGG160404R TNGG160408R TNGG160412R (STi10T) Holder : ETJNR33K16 (Side Cutting Edge ngle 3 ) Cutting Speed : vc=100m/min Dry Cutting (Note) Plese refer to pge N004 for chip shpes (A, B, C, D, E). N010
FORMULAE FOR CUTTING POWER ycutting POWER (Pc) Pc = Kc p f vc Kc 60 10 3 ( Work Mteril Mild Steel Medium Steel Hrd Steel Tool Steel Tool Steel Chrome Mngnese Steel Chrome Mngnese Steel Chrome Molybdenum Steel Chrome Molybdenum Steel Nickel Chrome Molybdenum Steel Nickel Chrome Molybdenum Steel Hrd Cst Iron Meehnite Cst Iron Grey Cst Iron (kw) (Problem) Wht is the cutting power required for mchining mild steel t cutting speed 120m/min with depth of cut 3mm nd feed 0.2mm/rev (Mchine coefficient 80%)? Tensile Strength(MP) nd Hrdness Pc (kw) : Actul Cutting Power p (mm) : Depth of Cut f (mm/rev) : Feed per Revolution vc (m/min) : Cutting Speed Kc (MP) : Specific Cutting Force ( : (Mchine Coefficient) (Answer) Substitute the specific cutting force Kc=3100MP into the formul. Pc = 3 0.2 120 3100 = 4.65 60 10 3 0.8 (kw) Specific Cutting Force Kc (MP) 0.1 (mm/rev) 0.2 (mm/rev) 0.3 (mm/rev) 0.4 (mm/rev) 0.6 (mm/rev) 520 3610 3100 2720 2500 2280 620 3080 2700 2570 2450 2300 720 4050 3600 3250 2950 2640 670 3040 2800 2630 2500 2400 770 3150 2850 2620 2450 2340 770 3830 3250 2900 2650 2400 630 4510 3900 3240 2900 2630 730 4500 3900 3400 3150 2850 600 3610 3200 2880 2700 2500 900 3070 2650 2350 2200 1980 352HB 3310 2900 2580 2400 2200 46HRC 3190 2800 2600 2450 2270 360 2300 1930 1730 1600 1450 200HB 2110 1800 1600 1400 1330 ycutting SPEED (vc) vc = ) Dm n 1000 (m/min) vc (m/min) : Cutting Speed Dm (mm) : Workpiece Dimeter ) (3.14) : Pi n (min -1 ) : Min Axis Spindle Speed Divide by 1000 to chnge to m from mm. (Problem) Wht is the cutting speed when min xis spindle speed is 700min -1 nd externl dimeter is &50? (Answer) Substitute )=3.14, Dm=50, n=700 into the formul. vc = ) Dm n = 3.14 50 700 = 110m/min 1000 1000 Cutting speed is 110m/min. yfeed (f) f = l n (mm/rev) (Problem) Wht is the feed per revolution when min xis spindle speed is 500min -1 nd cutting length per minute is 120mm/min? (Answer) Substitute n=500, I=120 into the formul. f = l = 120 = 0.24mm/rev n 500 The nswer is 0.24mm/rev. f (mm/rev) : Feed per Revolution I (mm/min) : Cutting Length per Min. n (min -1 ) : Min Axis Spindle Speed f l ødm n n ycutting TIME (Tc) ytheoretical FINISHED SURFACE ROUGHNESS (h) Tc= Im l (min) Tc (min) : Cutting Time Im (mm) : Workpiece Length I (mm/min): Cutting Length per Min. (Problem) Wht is the cutting time when 100mm workpiece is mchined t 1000min -1 with feed = 0.2mm/rev? h= f 2 8RE 1000(!m) h (!m) : Finished Surfce Roughness f (mm/rev) : Feed per Revolution RE (mm) : Insert Corner Rdius (Problem) Wht is the theoreticl finished surfce roughness when the insert corner rdius is 0.8mm nd feed is 0.2mm/rev? (Answer) First, clculte the cutting length per min. from the feed nd spindle speed. (Answer) Substitute f=0.2mm/rev, RE=0.8 into the formul. I = f n = 0.2 1000 = 200mm/min h = 0.22 1000 = 6.25!m 8 0.8 Substitute the nswer bove into the formul. The theoreticl finished surfce roughness is 6!m. Tc = Im = 100 = 0.5min l 200 Feed Feed 0.5 x 60=30 (sec.) The nswer is 30 sec. Depth of Cut Theoreticl Finished Surfce Roughness Depth of Cut Theoreticl Finished Surfce Roughness Lrge Corner Rdius Smll Corner Rdius N011
TROUBLE SHOOTING FOR FACE MILLING Deteriortion of Tool Life Deteriortion of Surfce Finish Burr, Workpiece Chipping Trouble Insert wer quickly generted Chipping or frcturing of cutting edge Poor finished surfce Not prllel or irregulr surfce Burrs, chipping Workpiece edge chipping Solution Fctors tool grde cutting edge geometry cutting speed tool grde cutting conditions Lck of cutting edge strength. Therml crck occurs Build-up edge occurs Lck of rigidity cutting conditions Welding occurs Poor run-out ccurcy Chttering Workpiece bending Tool clernce Lrge bck force Chip thickness is too lrge Cutter dimeter is too lrge Low shrpness A lrge corner ngle cutting conditions Low shrpness A smll corner ngle Chttering Insert Grde Selection Select hrder grde Select tougher grde Select grde with better therml shock resistnce Select grde with better dhesion resistnce Cutting speed Feed Up Down Wet Dry Wet Cutting Conditions Wet Depth of cut Engge ngle Up Coolnt Do not use wtersoluble cutting fluid Determine dry or wet cutting Rke Corner ngle Up Down Style nd Design of the Tool Honing strengthens the cutting edge Mchine, Instlltion of Tool Cutter dimeter Number of teeth Smller Lrger Wider chip pocket Use of wiper insert Improve run-out ccurcy Cutter rigidity Increse clmping rigidity of the tool nd workpiece Decrese overhng Decrese power nd mchine bcklsh Chip Control Poor chip dispersl, chip jmming nd chip pcking Welding occurs Chip thickness is too thin Cutter dimeter is too smll Poor chip disposl Wet N012
FUNCTION OF TOOL FEATURES FOR FACE MILLING yfunction OF EACH CUTTING EDGE ANGLE IN FACE MILLING Axil Rke Angle Led (GAMP) Angle (KAPR) Wiper Insert Min Cutting Edge Cutting Edge True Rke Angle (T) Inclintion (I) Rdil Rke Angle (GAMF) Ech Cutting Edge Angle in Fce Milling Type of Angle Symbol Function Effect Axil Rke Angle Rdil Rke Angle Led Angle True Rke Angle Cutting Edge Inclintion GAMP GAMF KAPR T I Determines chip disposl direction. Determines shrpness. Determines chip thickness. Determines ctul shrpness. Determines chip disposl direction. Positive : Excellent mchinbility. Negtive : Excellent chip disposl. Smll : Thin chips nd smll cutting impct. Lrge bck force. Positive (lrge) : Excellent mchinbility. Miniml welding. Negtive (lrge) : Poor mchinbility. Strong cutting edge. Positive (lrge) : Excellent chip disposl. Low cutting edge strength. ystandard INSERTS Positive nd Negtive Rke Angle Stndrd Cutting Edge Shpe Negtive Rke Angle Neutrl Rke Angle Positive Rke Angle (-) 0 (+ ) (+ ) Axil Rke Angle (-) Axil Rke Angle (+ ) Axil Rke Angle Stndrd Cutting Edge Combintions Rdil Rke Angle Rdil Rke Angle Rdil Rke Angle (+ ) (-) (-) Insert shpe whose cutting edge precedes is positive rke ngle. Insert shpe whose cutting edge follows is negtive rke ngle. Double Positive (DP Edge Type) Double Negtive (DN Edge Type) Negtive/Positive (NP Edge Type) Axil Rke Angle (GAMP) Positive ( + ) Negtive ( ) Positive ( + ) Rdil Rke Angle (GAMF) Positive ( + ) Negtive ( ) Negtive ( ) Insert Used Positive Insert (One Sided Use) Negtive Insert (Double Sided Use) Positive Insert (One Sided Use) Work Mteril Steel Cst Iron Aluminium Alloy Difficult-to-Cut Mteril ylead ANGLE (KAPR) AND CUTTING CHARACTERISTICS Cutting Resistnce (N) 3000 Led Angle : 90 Led Angle : 75 Led Angle : 45 2500 2000 Principl Principl Principl Force Force Force 1500 1000 500 Feed Force 0.1 0.2 0.3 Feed Force Bck Force Feed Force Bck Force 0 0.1 0.2 0.3 0.1 0.2 0.3 Bck Force -500 fz (mm/t) fz (mm/t) fz (mm/t) Workpiece : DIN 41CrMo4 (281HB) Tool : ø125mm Single Insert Cutting Conditions : vc=125.6m/min p=4mm e=110mm Cutting Resistnce Comprison between Different Insert Shpes Principl Force Feed Force Bck Force Tble Feed Three Cutting Resistnce Forces in Milling p e Led Angle 90 Bck force is in the minus direction. Lifts the workpiece when workpiece clmp rigidity is low. Led Angle 75 Led ngle 75 is recommended for fce milling of workpieces with low rigidity such s thin workpieces. Led Angle 45 The lrgest bck force. Bends thin workpieces nd lowers cutting ccurcy. Prevents workpiece edge chipping when cst iron cutting. Led Angle 90 Led Angle 75 Led Angle 45 Principl force : Force is in the opposite direction of fce milling rottion. Bck force : Force tht pushes in the xil direction. Feed force : Force is in the feed direction nd is cused by tble feed. N013
FUNCTION OF TOOL FEATURES FOR FACE MILLING ylead ANGLE AND TOOL LIFE Led ngle nd chip thickness When the depth of cut nd feed per tooth, fz, re fixed, the smller the led ngle (KAPR) is, then the thinner the chip thickness (h) becomes (for 45 KAPR, it is pprox. 75% tht of 90 KAPR). Therefore s the KAPR increses, the cutting resistnce decreses resulting in longer tool life. KAPR:90 KAPR:75 KAPR:45 h=fz 90 h=0.96fz 75 45 h=0.75fz fz fz fz Effects on chip thickness due to the vrition of led ngles Led ngle nd crter wer The tble below shows wer ptterns for different led ngles. When compring crter wer for 90 nd 45 led ngles, it cn be clerly seen tht the crter wer for 90 led ngle is lrger. This is becuse if the chip thickness is reltively lrge, the cutting resistnce increses nd so promotes crter wer. As the crter develops then cutting edge strength will reduce nd led to frcturing. Led Angle 90 Led Angle 75 Led Angle 45 vc=100m/min Tc=69min vc=125m/min Tc=55min vc=160m/min Tc=31min Workpiece : Alloy steel (287HB) Tools : DC=125mm Insert : M20Cemented Crbide Cutting Conditions : p=3.0mm e=110m fz=0.2mm/t Dry Cutting yup AND DOWN CUT (CLIMB) MILLING When choosing method to mchine, up cutting or down cut milling (climb milling) is decided by the conditions of the mchine tool, the milling cutter nd the ppliction. However, it is sid tht in terms of tool life, down cut (climb) milling is more dvntgeous. Up Cut Tool rottion Workpiece movement direction Portion mchined Down Cut Tool rottion Workpiece movement direction Milling cutter inserts Milling cutter inserts Portion mchined N014
yfinished SURFACE Cutting Edge Run-out Accurcy Cutting edge run-out ccurcy of indexble inserts on the cutter body gretly ffects the surfce finish nd tool life. Peripherl Cutting Edge Minor Cutting Edge Run-out Lrge Smll Poor Finished Surfce Good Finished Surfce Chipping Due to Vibrtion Rpid Wer Growth Stble Tool Life Shorten Tool Life Cutting Edge Run-out nd Accurcy in Fce Milling Improve Finished Surfce Roughness 1 2 3 4 5 6 1 f fz : Feed per Tooth f : Feed per Revolution Cutting Edge No. fz Sub Cutting Edge Run-out nd Finished Surfce D.O.C Tble Feed Since Mitsubishi Mterils' norml sub cutting edge width is 1.4mm, nd the sub cutting edges re set prllel to the fce of milling cutter, theoreticlly the finished surfce ccurcy should be mintined even if run-out ccurcy is low. Actul Problems Cutting edge run-out. Sub cutting edge inclintion. Milling cutter body ccurcy. Spre prts ccurcy. Welding, vibrtion, chttering. Countermesure Wiper Insert Mchine surfce tht hs lredy been mchined with norml inserts in order to produce smooth finished surfce. 1 Replce one or two norml inserts with wiper inserts. Wiper inserts re set to protrude by 0.03 0.1mm Wiper Insert Stndrd Insert 0.03 0.1mm from the stndrd inserts. 1. Vlue depends on the cutting edge nd insert combintion. How to Set Wiper Insert Body Loctor () One Corner Type Replce norml insert. Body Loctor (b) Two Corner Type Replce norml insert. Body (c) Two Corner Type Use loctor for wiper insert. Loctor Sub cutting edge length hs to be longer thn the feed per revolution. A sub cutting edge tht is too long cuses chtter. When the cutter dimeter is lrge nd feed per revolution is longer thn the sub cutting edge of the wiper insert, use two or three wiper inserts. When using more thn 1 wiper insert, run-out needs to be eliminted. Use high hrdness grde (high wer resistnce) for wiper inserts. N015
FORMULAE FOR FACE MILLING ycutting SPEED (vc) vc = ) DC n 1000 DC n (m/min) Divide by 1000 to chnge to m from mm. vc (m/min) : Cutting Speed DC(mm) : Cutter Dimeter ) (3.14) : Pi n (min -1 ) : Min Axis Spindle Speed (Problem) Wht is the cutting speed when the min xis spindle speed is 350min -1 nd the cutter dimeter is &125? (Answer) Substitute )=3.14, DC=125, n=350 into the formul. vc = ) DC n = 3.14 125 350 = 137.4m/min 1000 1000 The cutting speed is 137.4m/min. yfeed PER TOOTH (fz) fz = vf z n Feed per Tooth (fz) (mm/t) Feed Direction Wiper Edge Angle Tooth Mrk fz (mm/t) : Feed per Tooth z : Insert Number vf (mm/min) : Tble Feed per Min. n (min -1 ) : Min Axis Spindle Speed (Feed per Revolution f = z x fz) (Problem) Wht is the feed per tooth when the min xis spindle speed is 500min -1, insert number is 10, nd the tble feed is 500mm/min? (Answer) Substitute the bove figures into the formul. fz = vf 500 = = 0.1mm/t z n 10 500 The nswer is 0.1mm/t ytable FEED (vf) vf = fz z n (mm/min) n vf (mm/min) : Tble Feed per Min. z : Insert Number fz (mm/t) : Feed per Tooth n (min -1 ) : Min Axis Spindle Speed (Problem) Wht is the tble feed when feed per tooth is 0.1mm/t, insert number is 10, nd the min xis spindle speed is 500min -1? (Answer) Substitute the bove figures into the formul. vf = fz z n = 0.1 10 500 = 500mm/min The tble feed is 500mm/min. ycutting TIME (Tc) Tc= DC L vf L (min) l Tc (min) : Cutting Time vf (mm/min) : Tble Feed per Min. L (mm) : Totl Tble Feed Length (Workpiece Length: l+cutter Dimeter : DC) (Problem) Wht is the cutting time required for finishing 100mm width nd 300mm length surfce of cst iron (GG20) block when the cutter dimeter is &200, the number of inserts is 16, the cutting speed is 125m/min, nd feed per tooth is 0.25mm. (spindle speed is 200min -1 ) (Answer) Clculte tble feed per min vf=0.25 16 200=800mm/min Clculte totl tble feed length. L=300+200=500mm Substitute the bove nswers into the formul. Tc = 500 = 0.625 800 (min) 0.625 60=37.5 (sec). The nswer is 37.5 sec. N016
ycutting POWER (Pc) Pc = p e vf Kc 60 10 6 ( Pc (kw) : Actul Cutting Power p (mm) : Depth of Cut e (mm) : Cutting Width vf (mm/min) : Tble Feed per Min. Kc (MP) : Specific Cutting Force ( : (Mchine Coefficient) (Problem) Wht is the cutting power required for milling tool steel t cutting speed of 80m/min. With depth of cut 2mm, cutting width 80mm, nd tble feed 280mm/min by &250 cutter with 12 inserts. Mchine coefficient 80%. Kc Mild Steel Work Mteril Tensile Strength (MP) nd Hrdness (Answer) First, clculte the spindle speed in order to obtin the feed per tooth. n = 1000vc 1000 80 = = 101.91 min ) DC 3.14 250-1 fz = vf 280 Feed per Tooth = = 0.228mm/t z n 12 101.9 Substitute the specific cutting force into the formul. Pc = 2 80 280 1800 60 10 6 0.8 = 1.68 kw Specific Cutting Force Kc (MP) 0.1mm/t 0.2mm/t 0.3mm/t 0.4mm/t 0.6mm/t 520 2200 1950 1820 1700 1580 Medium Steel Hrd Steel Tool Steel Tool Steel Chrome Mngnese Steel Chrome Mngnese Steel Chrome Molybdenum Steel Chrome Molybdenum Steel Nickel Chrome Molybdenum Steel Nickel Chrome Molybdenum Steel Austenitic Stinless Steel Cst Iron Hrd Cst Iron Meehnite Cst Iron Grey Cst Iron Brss Light Alloy (Al-Mg) Light Alloy (Al-Si) Light Alloy (Al-Zn-Mg-Cu) 620 1980 1800 1730 1600 1570 720 2520 2200 2040 1850 1740 670 1980 1800 1730 1700 1600 770 2030 1800 1750 1700 1580 770 2300 2000 1880 1750 1660 630 2750 2300 2060 1800 1780 730 2540 2250 2140 2000 1800 600 2180 2000 1860 1800 1670 940 2000 1800 1680 1600 1500 352HB 2100 1900 1760 1700 1530 155HB 2030 1970 1900 1770 1710 520 2800 2500 2320 2200 2040 46HRC 3000 2700 2500 2400 2200 360 2180 2000 1750 1600 1470 200HB 1750 1400 1240 1050 970 500 1150 950 800 700 630 160 580 480 400 350 320 200 700 600 490 450 390 570 880 840 840 810 720 N017
TROUBLE SHOOTING FOR END MILLING Deteriortion of Tool Life Deteriortion of Surfce Finish Burrs, Chipping, etc. Poor Chip Dispersl Trouble Lrge peripherl cutting edge wer Severe chipping Brekge during cutting Vibrtion during cutting Poor surfce finish on wlls Poor surfce finish on fces Out of verticl Poor dimensionl ccurcy Burr or chipping occurs Quick bur formtion Chip pcking Solution Fctors Non-coted end mill is used A smll number of cutting edges cutting conditions Up cut milling is used cutting conditions Frgile cutting edge Insufficient clmping force Low clmping rigidity cutting conditions Low end mill rigidity Overhng longer thn necessry Chip jmming cutting conditions Low end mill rigidity Low clmping rigidity Lrge cutting edge wer cutting conditions Chip pcking. The end cutting edge does not hve concve ngle Lrge pick feed Lrge cutting edge wer cutting conditions Lck of end mill rigidty cutting conditions Low clmping rigidity cutting conditions Lrge helix ngle Notch wer cutting conditions Metl removl too lrge Lck of chip pocket Insert Grde Selection Coted tool Cutting speed Wet Feed Cutting Conditions Up Down Depth of cut Pick feed Down Down cut Down Cut Use ir blow Coolnt Increse coolnt quntity Do not use wtersoluble cutting fluid Determine dry or wet cutting Style nd Design of the Tool Helix ngle Insert number Concvity ngle of end cutting edge Tool dimeter Up Lrger Down Smller Cutter rigidity Wider chip pocket Mchine, Instlltion of Tool Shorten tool overhng Increse tool instlltion ccurcy Increse spindle collet run-out ccurcy Collet inspection nd exchnge Increse chuck clmping power Increse work clmping rigidity N018
END MILL FEATURES AND SPECIFICATION ynomenclature Run-out Neck Flute Shnk Dimeter Shnk dimeter Length of cut Overll length Lnd width Primry clernce lnd Rdil primry clernce ngle Rdil secondry clernce ngle Rdil rke ngle Corner End cutting edge End gsh Axil rke ngle Concvity ngle of end cutting edge Peripherl cutting edge Helix ngle Axil primry relief ngle Axil secondry clernce ngle ycomparison OF SECTIONAL SHAPE AREA OF CHIP POCKET 2-flutes 50% 3-flutes 45% 4-flutes 40% 6-flutes 20% ycharacteristics AND APPLICATIONS OF DIFFERENT-NUMBER-OF-FLUTE END MILLS Feture Advntge Fult Chip disposbility is excellent. Drillng is esy. Low rigidity 2-flutes 3-flutes 4-flutes 6-flutes Chip disposbility is excellent. Suitble for sinking. Dimeter is not mesured esily. High rigidity Chip disposbility is poor. High rigidity. Superior cutting edge durbility. Chip disposbility is poor. Usge Slotting, side milling, sinking. Wide rnge of use. Slotting, side milling Hevy cutting, finishing Shllow slotting, side milling Finishing High Hrdness Mteril Shllow slotting, side milling N019
END MILL FEATURES AND SPECIFICATION ytype AND GEOMETRY (1) Peripherl Cutting Edge Type Shpe Feture Ordinry Flute Regulr flute geometry s shown is most commonly used for roughing nd finishing of side milling, slotting nd shoulder milling. Tpered Flute A tpered flute geometry is used for specil pplictions such s mould drfts nd for pplying tper ngles fter conventionl stright edged milling. Roughing Flute Formed Flute Roughing type geometry hs wve like edge form nd breks the mteril into smll chips. Additionlly the cutting resistnce is low enbling high feed rtes when roughing. The inside fce of the flute is suitble for regrinding. Specil form geometry s shown is used for producing corner rdii on components. There re n infinite number of different geometries tht cn be mnufctured using such style of cutters. (2) End Cutting Edge Type Shpe Feture Squre End (With Centre Hole) Generlly used for side milling, slotting nd shoulder milling. Plunge cutting is not possible due to the centre hole tht is used to ensure ccurte grinding nd regrinding of the tool. Squre End (Centre Cut) Generlly used for side milling, slotting nd shoulder milling. Plunge cutting is possible nd greter plunge cutting efficiency is obtined when using fewer flutes. Regrinding on the flnk fce cn be done. Bll End Geometry completely suited for curved surfce milling. At the extreme end point the chip pocket is very smll leding to inefficient chip evcution. Corner Rdius End Used for rdius profiling nd corner rdius milling. When pick feed milling n end mill with lrge dimeter nd smll corner rdius cn be used efficiently. (3) Shnk And Neck Prts Type Shpe Feture Stndrd (Stright Shnk) Long Shnk Most widely used type. Long shnk type for deep pocket nd shoulder pplictions. Long Neck Long neck geometry cn be used for deep slotting nd is lso suitble for boring. Tper Neck Long tper neck fetures re best utilised on deep slotting nd mould drft pplictions. N020
PITCH SELECTION OF PICK FEED ypick FEED MILLING (CONTOURING) WITH BALL NOSE END MILLS AND END MILLS WITH CORNER RADII End mill h h= RE 1 cos sin -1 ( P ) 2RE RE RE : Rdius of Bll Nose, Corner Rdius P P h : Pick Feed : Cusp Height ycorner R OF END MILLS AND CUSP HEIGHT BY PICK FEED P Pitch of Pick Feed (P) Unit : mm RE 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0. 5 0.003 0.010 0.023 0.042 0.067 0.100 1 0.001 0.005 0.011 0.020 0.032 0.046 0.063 0.083 0.107 1. 5 0.001 0.003 0.008 0.013 0.021 0.030 0.041 0.054 0.069 0.086 2 0.001 0.003 0.006 0.010 0.016 0.023 0.031 0.040 0.051 0.064 2. 5 0.001 0.002 0.005 0.008 0.013 0.018 0.025 0.032 0.041 0.051 3 0.002 0.004 0.007 0.010 0.015 0.020 0.027 0.034 0.042 4 0.001 0.003 0.005 0.008 0.011 0.015 0.020 0.025 0.031 5 0.001 0.002 0.004 0.006 0.009 0.012 0.016 0.020 0.025 6 0.001 0.002 0.003 0.005 0.008 0.010 0.013 0.017 0.021 8 0.001 0.003 0.004 0.006 0.008 0.010 0.013 0.016 10 0.001 0.002 0.003 0.005 0.006 0.008 0.010 0.013 12. 5 0.001 0.002 0.003 0.004 0.005 0.006 0.008 0.010 P Pitch of Pick Feed (P) RE 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 0. 5 1 1. 5 0.104 2 0.077 0.092 0.109 2. 5 0.061 0.073 0.086 0.100 3 0.051 0.061 0.071 0.083 0.095 0.109 4 0.038 0.045 0.053 0.062 0.071 0.081 0.091 0.103 5 0.030 0.036 0.042 0.049 0.057 0.064 0.073 0.082 0.091 0.101 6 0.025 0.030 0.035 0.041 0.047 0.054 0.061 0.068 0.076 0.084 8 0.019 0.023 0.026 0.031 0.035 0.040 0.045 0.051 0.057 0.063 10 0.015 0.018 0.021 0.025 0.028 0.032 0.036 0.041 0.045 0.050 12. 5 0.012 0.014 0.017 0.020 0.023 0.026 0.029 0.032 0.036 0.040 N021
TROUBLE SHOOTING FOR DRILLING Deteriortion of Tool Life Deteriortion of Hole Accurcy Burrs Poor Chip Dispersl Trouble Drill brekge Lrge wer t the peripherl cutting edge nd long the lnd Chipping of the peripherl cutting edge Chisel edge chipping Hole dimeter increses Hole dimeter becomes smller Poor strightness Poor hole positioning ccurcy, roundness nd surfce finish Burrs t the hole exit Long chips Chip jmming Solution Fctors Lck of drill rigidity cutting conditions Lrge deflection of the tool holder Workpiece fce is inclined cutting conditions An increse in temperture t the cutting point Poor run-out ccurcy cutting conditions Lrge deflection of the tool holder Chttering, vibrtion The chisel edge width is too wide Poor entry Chttering, vibrtion Lck of drill rigidity drill geometry An increse in temperture t the cutting point cutting conditions drill geometry Lck of drill rigidity Lrge deflection of the tool holder Poor guiding properties Lck of drill rigidity Poor entry cutting conditions Lrge deflection of the tool holder drill geometry cutting conditions cutting conditions Poor chip disposl cutting conditions Poor chip disposl Cutting speed Up Down Feed Cutting Conditions Lower feed t initil cutting Lower feed when breking through Step feed Increse ccurcy of prep-hole nd depth Increse oil rtio Coolnt Increse volume Increse coolnt pressure Chisel width Style nd Design of the Tool Honing width Up Down Core thickness Shorten flute length Decrese lip height Use internl coolnt type drill Chnge to drill with X type thinning Increse tool instlltion ccurcy Mchine, Instlltion of Tool Shorten tool overhng Flt workpiece fce Increse work clmping rigidity Reduce mchine bcklsh nd increse rigidity N022
DRILL WEAR AND CUTTING EDGE DAMAGE ydrill WEAR CONDITION The tble below shows simple drwing depicting the wer of drill s cutting edge. The genertion nd the mount of wer differ ccording to the workpiece mterils nd cutting conditions used. But generlly, the peripherl wer is lrgest nd determines drills tool life. When regrinding, the flnk wer t the point needs to be ground wy completely. Therefore, if there is lrge wer more mteril needs to be ground wy to renew the cutting edge. We : Chisel edge wer width We Wf : Flnk Wer (The middle of the cutting edge) Wo Wf Wo : Outer corner wer width Wm : Mrgin wer width Wm' : Mrgin wer width (Leding edge) Wm Wm' ycutting EDGE DAMAGE When drilling, the cutting edge of the drill cn suffer from chipping, frcture nd bnorml dmge. In such cses, it is importnt to tke closer look t the dmge, investigte the cuse nd tke countermesures. b c b Cutting edge dmge c N023
DRILL FEATURES AND SPECIFICATION ynomenclature Stright shnk with tng Height of point Functionl length Clernce ngle Body Flnk Led Helix ngle Neck Tper shnk Tng Drill dimeter Outer corner Point ngle Axis Flute length Shnk length Overll length Neck length Mrgin width Mrgin Depth of body clernce Body clernce Chisel edge ngle Lnd width Flute Flute width Cutting edge yshape SPECIFICATION AND CUTTING CHARACTERISTICS Helix Angle It is the inclintion of the flute with respect to the xil direction of drill, which corresponds to the rke ngle of bit. The rke ngle of drill differs ccording to the position of the cutting edge, nd it decreses gretly s the circumference pproches the centre. High-hrdness mteril Smll Rke ngle Lrge Soft mteril (Aluminium, etc.) Flute Length It is determined by depth of hole, bush length, nd regrinding llownce. Since the influence on the tool life is gret, it is necessry to minimize it s much s possible. Point Angle Web Thickness Mrgin A stndrd point ngle is 118 nd be chnged to suit different pplictions. Soft mteril with good mchinbility Smll Point ngle Lrge The tip determines the drill dimeter nd functions s drill guide during drilling. The mrgin width is determined in considertion of friction with drilled hole. Poor guiding performnce Smll Mrgin width For hrd mteril nd high-efficiency mchining It is n importnt element tht determines the rigidity nd chip breking performnce of drill. The web thickness is set ccording to pplictions. Lrge cutting resistnce Smll cutting resistnce High rigidity Low rigidity Thin Web thickness Thick Poor chip rking performnce Good chip rking performnce High-hrdness mteril, Mchinble mteril cross hole drilling, etc. Lrge Good guiding performnce Dimeter Bck Tper To reduce friction with the inside of the drilled hole, the portion of the flute from the tip to the shnk is tpered slightly. The degree of tper is usully represented by the quntity of reduction in the dimeter with respect to the flute length, which is pprox. 0.04 0.1mm. It is set t lrger vlue for high-efficiency drills nd the work mteril tht llows drilled holes to be closed. N024
ycutting EDGE GEOMETRY AND ITS INFLUENCE As shown in the tble below, it is possible to select the most suitble cutting edge geometry for different pplictions. If the most suitble cutting edge geometry is selected then higher mchining efficiency nd higher hole ccurcy cn be obtined. Cutting Edge Shpes Grinding nme Shpe Fetures nd effect Appliction Conicl The flnk is conicl nd the clernce ngle increses towrd the centre of the drill. Generl Use Flt The flnk is flt. Esy grinding. Minly for smll dimeter drills. Three flnk ngles As there is no chisel edge, the results re high centripetl force nd smll hole oversize. Requires specil grinding mchine. Surfce grinding of three sides. For drilling opertions tht require high hole ccurcy nd positioning ccurcy. Spirl point To increse the clernce ngle ner the centre of the drill, conicl grinding combined with irregulr helix. S type chisel edge with high centripetl force nd mchining ccurcy. For drilling tht requires high ccurcy. Rdil lip Centre Point drill The cutting edge is ground rdil with the im of dispersing lod. High mchining ccurcy nd finished surfce roughness. For through holes, smll burrs on the bse. Requires specil grinding mchine. This geometry hs two-stge point ngle for better concentricity nd reduction in shock when exiting the workpiece. Cst Iron, Aluminium Alloy For cst iron pltes. Steel For thin sheet drilling. yweb THINNING The rke ngle of the cutting edge of drill reduces towrd the centre, nd it chnges into negtive ngle t the chisel edge. During drilling, the centre of drill crushes the work, generting 50 70% of the cutting resistnce. Web thinning is very effective for reduction in the cutting resistnce of drill, erly removl of cut chips t the chisel edge, nd better biting. Shpe Fetures Mjor Applictions X type XR type S type N type The thrust lod substntilly reduces, nd the biting performnce improves. This shpe is effective when the web is rther thick. Generl drilling nd deep hole drilling. The biting performnce is slightly inferior to tht of X type, but the cutting edge is hrd nd the pplicble rnge of work is wide. Long life. Generl drilling nd stinless steel drilling. Cutting is esy. This shpe is generlly used. Generl drilling for steel, cst iron, nd non-ferrous metl. Effective when the web is comprtively thick. Deep hole drilling. N025
DRILL FEATURES AND SPECIFICATION ydrilling CHIPS Types of Chips Shpe Fetures nd Ese of Rking Conicl Spirl Fn-shped chips cut by the cutting edge re curved by the flute. Chips of this type re produced when drilling ductile mteril t smll feed rte. If the chip breks fter severl turns, the chip breking performnce is stisfctory. Long Pitch Long pitch chips exit without curling nd will esily coil round the drill. Fn This is chip broken by the drill flute nd the wll of drilled hole. It is generted when the feed rte is high. Segment A conicl spirl chip tht is broken just before the chip grows into the long-pitch shpe by the wll of the drilled hole due to its insufficient ductility. Excellent chip disposl nd chip dischrge. Zigzg A chip tht is buckled nd folded becuse of the shpe of flute nd the chrcteristics of the mteril. It esily cuses chip pcking t the flute. Needle Chips broken by vibrtion or broken when brittle mteril is curled with smll rdius. The breking performnce is comprtively stisfctory, but these chips cn become closely pcked. N026
FORMULAE FOR DRILLING ycutting SPEED (vc) vc = ) DC n 1000 (m/min) Unit trnsformtion (from "mm" to "m") n vc (m/min) : Cutting Speed DC (mm) : Drill Dimeter ) (3.14) : Pi n (min -1 ) : Rottionl Speed of the Min Spindle (Problem) Wht is the cutting speed when the min xis spindle speed is 1350min -1 nd drill dimeter is 12mm? (Answer) Substitute )=3.14, DC=12, n=1350 into the formul vc = ) DC n = 3.14 12 1350 = 50.9m/min 1000 1000 The cutting speed is 50.9m/min. DC yfeed OF THE MAIN SPINDLE (vf) vf = fr n(mm/min) vf (mm/min) : Feed Speed of the Min Spindle (Z xis) fr (mm/rev) : Feed per Revolution n (min -1 ) : Rottionl Speed of the Min Spindle vf n (Problem) Wht is the spindle feed (vf) when the feed per revolution is 0.2mm/rev nd the min xis spindle speed is 1350min -1? (Answer) Substitute fr=0.2, n=1350 into the formul vf = fr n = 0.2 1350 = 270mm/min The spindle feed is 270mm/min. fr ydrilling TIME (Tc) Tc = Id i n fr n Tc (min) : Drilling Time n (min -1 ) : Spindle Speed ld (mm) : Hole Depth fr (mm/rev): Feed per Revolution i : Number of Holes (Problem) Wht is the drilling time required for drilling 30mm length hole in lloy steel t cutting speed of 50m/min nd feed 0.15mm/rev? (Answer) Spindle Speed n = 50 1000 = 1061.57min 15 3.14-1 30 1 Tc = = 0.188 1061.57 0.15 = 0.188 60i11.3 sec ld N027
METALLIC MATERIALS CROSS REFERENCE LIST ycarbon STEEL Germny U.K. Frnce Itly Spin Sweden Jpn USA Chin W-nr. DIN BS EN AFNOR UNI UNE SS JIS AISI/SAE GB 1.0038 RSt.37-2 4360 40 C E 24-2 Ne 1311 STKM 12A A570.36 STKM 12C 15 1.0401 C15 080M15 CC12 C15, C16 F.111 1350 1015 15 1.0402 C22 050A20 2C CC20 C20, C21 F.112 1450 1020 20 1.0715 9SMn28 230M07 1A S250 CF9SMn28 F.2111 11SMn28 1912 SUM22 1213 Y15 1.0718 9SMnPb28 S250Pb CF9SMnPb28 11SMnPb28 1914 SUM22L 12L13 1.0722 10SPb20 10PbF2 CF10Pb20 10SPb20 1.0736 9SMn36 240M07 1B S300 CF9SMn36 12SMn35 1215 Y13 1.0737 9SMnPb36 S300Pb CF9SMnPb36 12SMnP35 1926 12L14 1.1141 Ck15 080M15 32C XC12 C16 C15K 1370 S15C 1015 15 1.1158 Ck25 S25C 1025 25 1.8900 StE380 4360 55 E FeE390KG 2145 A572-60 1.0501 C35 060A35 CC35 C35 F.113 1550 1035 35 1.0503 C45 080M46 CC45 C45 F.114 1650 1045 45 1.0726 35S20 212M36 8M 35MF4 F210G 1957 1140 1.1157 40Mn4 150M36 15 35M5 1039 40Mn 1.1167 36Mn5 40M5 36Mn5 2120 SMn438(H) 1335 35Mn2 1.1170 28Mn6 150M28 14A 20M5 C28Mn SCMn1 1330 30Mn 1.1183 Cf35 060A35 XC38TS C36 1572 S35C 1035 35Mn 1.1191 Ck45 080M46 XC42 C45 C45K 1672 S45C 1045 Ck45 1.1213 Cf53 060A52 XC48TS C53 1674 S50C 1050 50 1.0535 C55 070M55 9 C55 1655 1055 55 1.0601 C60 080A62 43D CC55 C60 1060 60 1.1203 Ck55 070M55 XC55 C50 C55K S55C 1055 55 1.1221 Ck60 080A62 43D XC60 C60 1678 S58C 1060 60Mn 1.1274 Ck101 060A96 XC100 F.5117 1870 1095 1.1545 C105W1 BW1A Y105 C36KU F.5118 1880 SK3 W1 1.1545 C105W1 BW2 Y120 C120KU F.515 2900 SUP4 W210 y ALLOY STEEL Germny U.K. Frnce Itly Spin Sweden Jpn USA Chin W-nr. DIN BS EN AFNOR UNI UNE SS JIS AISI/SAE GB 1.0144 St.44.2 4360 43 C E28-3 1412 SM400A, SM400B A573-81 SM400C 1.0570 St52-3 4360 50 B E36-3 Fe52BFN Fe52CFN 2132 SM490A, SM490B SM490C 1.0841 St52-3 150M19 20MC5 Fe52 F.431 2172 5120 1.0904 55Si7 250A53 45 55S7 55Si8 56Si7 2085 9255 55Si2Mn 1.0961 60SiCr7 60SC7 60SiCr8 60SiCr8 9262 1.3505 100Cr6 534A99 31 100C6 100Cr6 F.131 2258 SUJ2 ASTM 52100 Gr15, 45G 1.5415 15Mo3 1501-240 15D3 16Mo3KW 16Mo3 2912 ASTM A204Gr.A 1.5423 16Mo5 1503-245-420 16Mo5 16Mo5 4520 1.5622 14Ni6 16N6 14Ni6 15Ni6 ASTM A350LF5 1.5662 X8Ni9 1501-509-510 X10Ni9 XBNi09 ASTM A353 1.5710 36NiCr6 640A35 111A 35NC6 SNC236 3135 1.5732 14NiCr10 14NC11 16NiCr11 15NiCr11 SNC415(H) 3415 1.5752 14NiCr14 655M13 36A 12NC15 SNC815(H) 3415, 3310 1.6523 21NiCrMo2 805M20 362 20NCD2 20NiCrMo2 20NiCrMo2 2506 SNCM220(H) 8620 1.6546 40NiCrMo22 311-Type 7 40NiCrMo2(KB) 40NiCrMo2 SNCM240 8740 1.6587 17CrNiMo6 820A16 18NCD6 14NiCrMo13 1.7015 15Cr3 523M15 12C3 SCr415(H) 5015 15Cr N028