Общий каталог Sumitomo 2018 - 2019 - страница 557

Technical Guidance Basics of Turning Calculating Power Requirement Cutting Force Cutting Speed and Cutting Force Rake angle: -10° Principal force (N) 1600 F2 Pc : Net power requirement (KW) v c : Cutting speed (m/min) 800 doc . f . vc . K c Rake angle: 0° Pc = f : Feed rate (mm/rev) F3 60 5 10 3 5 η ap : Depth of cut (mm) 0 0 80 160 240 F1 η : Machine efficiency Cutting speed (m/min) F1 : Principal force Pc (0,70 ~ 0,85) H = 0,75 K c : Specific cutting force (N/mm2) F2 : Feed force Rake Angle and Cutting Force F3 : Back force H : Required horsepower (HP) l Calculating cutting force Principal force (N) 2800 P : Cutting force (N) l Rough value of specific cutting force (Kc) P= Kc . q Kc : Specific cutting force (N/mm2) 2400 General steel : 2.500 ~ 3.000 N/mm2 kc x doc x f q : Chip area (mm2) 2000 Cast iron : 1.500 N/mm2 = 1000 doc: Depth of cut (mm) 1600 Aluminum : 800 N/mm2 20 10 0 -10 -20 f : Feed rate (mm/rev) Rake angle (degree) Feed Rate and Specific Cutting Force Calculating Cutting Speed (For carbon steel) j Calculating rotational speed from cutting speed 8.000 Traverse n : Spindle speed (min -1) rupture 1000 . vc strength Specific cutting resistance (N/mm2) m vc : Cutting speed (m/min) n= n 800 N/mm2 π.D D : Diameter of workpiece (mm) 6.000 600 N/mm2 d oc π ≈ 3,14 400 N/mm2 (Eg.) vc =150m/min, D=100mm 1000 x 150 n= = 478 (min -1) 4.000 3,14 x 100 n : Spindle speed (min -1) k Calculating cutting speed from rotational speed v c : Cutting speed (m/min) 2.000 π.D.n f : Feed rate (mm/rev) vc = Refer to the above table doc : Depth of cut (mm) 1.000 Dm : Diameter of workpiece (mm) 0 0,1 0,2 0,4 1,0 0,04 Feed rate (mm/rev) When feed rate decreases, specific cutting force increases. Roughness Nose Radius and Cutting Force l Theoretical Surface Finish l Ways to Improve Surface Finish 4000 3500 Rz : Surface finish (mm) j Use an insert with a larger nose radius. Principal force Cutting force (N) f2 Rz = f : Feed rate (mm/rev) 8x r k Optimize the cutting speed and feed Feed force r : Nose radius (mm) 1500 rate so that built-up edge does not Rz occur. 1000 f Back force r 500 l Select an appropriate insert grade. 0,4 0,8 1,2 1,6 Nose radius (mm) m Use wiper insert. l Actual surface roughness Large nose radius increases back force. Steel : Work : 42CrMo4 (Hs38) Theoretical surface finish x 1,5 ~ 3 Inserts : TNGA2204 Cast iron : Holder : PTGNR2525-43 Theoretical surface finish x 3 ~ 5 Condition : v c =100m/min d oc =4mm f =0,45mm/rev Technical Guidance N2