Техническая информация Sumitomo - страница 9

Technical Guidance
Milling Edition Basics of Milling
■ Relation Between Engagement Angle and Tool Life


Relation to Cutter Position Relation to Cutter Diameter
Work material feed direction Vf Large Diameter Small Diameter
f f


Cutting Width W
Rotation DC DC
DC

E E
Small Large
Engagement angle E Insert
f
f
The Engagement angle denotes the angle
at which the full length of the cutting edge
comes in contact with the work material, E
with reference to the feed direction. Small E Large


Tool Life (Milling Area) (m2)
Tool Life (Milling Area) (m2)
· The larger E is, the shorter the


Relation to Tool Life
0.4
tool life. 0.3 0.6
FC250
S50C
· To change the value of E: 0.2 0.4
1) Increase the cutter size. 0.1 0.2
2) Shift the position of the cutter. -30° 0° 30° 60° -20° 0° 20° 40° 60° 80°
Engagement Angle Engagement Angle

● Relation between the number of simultaneously engaged cutting edges and cutting force: Normally, cutting width is considered to be appropriate with 70 to 80% of the cutter diameter engaged as shown in example
d). However, this may not apply due to the actual rigidity of the machine or work piece, and machine horsepower.
a) b) c) d) e)
Cutting


Cutting


Cutting


Cutting


Cutting
force


force


force


force


force
Time Time Time Time Time
material
Work


Cutter
· 0 or 1 edge in · Only 1 edge in · 1 or 2 edges in · 2 edge in · 2 to 3 edges in
contact at same contact at any time. contact. contact at any contact.
time. time.


■ To Improve Surface Roughness ● Surface roughness without wiper flat ● Influence of different face angles on surface finish
· Work : SCM435
(1) Inserts with wiper flat Feed rate Feed rate
per tooth per tooth · Cutter: DPG5160R
When all the cutting edges (Single tooth)
HC (A)
have wiper flats, a few teeth are · vc = 154m/min
fz = 0.234mm/t
intentionally elevated to play the
role of a wiper insert. ● Surface roughness with straight wiper flat Feed rate Feed rate
ap = 2mm
· Face Cutting Edge Angle
per tooth per tooth
· Insert equipped with straight wiper flat (A): 28'
(Face angle: 15' - 1°) (B) (B): 6'
×2,000
· Insert equipped with curved wiper flat HF ×100
(Curvature ≈ R500 (example))
h: Projection value of wiper insert ● Effects of having wiper insert (example)
( )
Fc: 0.05mm
(2) Wiper insert assembling system Al: 0.03mm
Wiper insert (Only · Work : FC250
normal ×1,000
A system to protrude one or Normal teeth) 20
20 · Cutter: DPG4100R
HW teeth 15
two inserts (wiper inserts) with (C) · Insert : SPCH42R
Roughness


10
(µm)


· Face run-out : 0.015mm
a smooth curved edge just a h 5
· Radial run-out: 0.04mm
Feed rate per rev.
little beyond the other teeth
to wipe the milled surface.
(Applies to WGC, RF types, etc.)
f : Feed rate per revolution (mm/rev) (With 1
wiper
insert) 20
×1,000
20
· vc = 105m/min
fz = 0.29mm/t
(1.45 mm/rev)
N
Technical Guidance /


15
(D) (C) : Only normal teeth
Roughness


References


10
(µm)


HC (D) : With 1 wiper insert
5
HW
Hc: Surface roughness with only normal teeth
Hw: Surface roughness with wiper insert


N17