Общий каталог Sumitomo 2018 - 2019 - страница 557

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Basics of Turning

Calculating Power RequirementCutting ForceCutting Speed and Cutting Force
Rake angle: -10°
1600
P : Net power requirement (KW)F 2
c
vc : Cutting speed (m/min)800
d . f . v. KRake angle: 0°
P =occ cf : Feed rate (mm/rev)F
cη3
60 510 3 5a: Depth of cut (mm)0
p0240 160 80
ηF 1
: Machine efficiencyF : Principal forceCutting speed (m/min)
P1
H =c(0,70 ~ 0,85)F : Feed forceRake Angle and Cutting Force

0,75 2 K : Specific cutting force (N/mm2) c F 3 : Back force H : Required horsepower (HP) Calculating cutting force

l 2800 Rough value of specific cutting force (K ) P : Cutting force (N)

l c 2400

P= Kc . qK :Specific cutting force (N/mm2)
c
General steel : 2.500 ~ 3.000 N/mm2k x dx fq : Chip area (mm2)2000
=c oc
Cast iron :1.500 N/mm 21000d: Depth of cut (mm)
oc1600
Aluminum :800 N/mm2f :Feed rate (mm/rev)-20 -10 0 10 20

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 . vstrength
n =cv c :Cutting speed (m/min)
π . DD :Diameter of workpiece (mm)800 N/mm2

6.000 600 N/mm2 π ≈ 3,14 400 N/mm2 (Eg.) v =150m/min, D=100mm

c 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 : Cutting speed (m/min) c 2.000

π . D . n f : Feed rate (mm/rev)

vc =Refer to the above tabled: Depth of cut (mm)
1.000oc
Dm : Diameter of workpiece (mm)
00,10,20,41,0
0,04Feed rate (mm/rev)
When feed rate decreases, specific cutting force increases.
RoughnessNose Radius and Cutting Force
l Theoretical Surface Finishl Ways to Improve Surface Finish4000
Rz : Surface finish (mm)j Use an insert with a larger nose radius.3500Principal force
f 2
Rz =f : Feed rate (mm/rev)

8 x r k Optimize the cutting speed and feed Feed force

r : Nose radius (mm) 1500 rate so that built-up edge does not occur. 1000 Rz

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 =100m/min

c d oc =4mm f =0,45mm/rev