Page 1030 - Tungaloy Catalog

Technical Reference
Milling Tools
Roughness of finished surface

(1) Theoretical surface roughness
Theoretical roughness as shown in Fig. 1, is the same as for single point turning
dWith corner R dWithout corner R
Rth: Theoretical roughness (µm)
Ћ Ќ fz: Feed per tooth (ipt)
r Џ Ћ Ќ r ε: Corner radius (in)
α : Corner angle
β : Face cutting edge angle

With corner R Without corner R

Rth Rth
r ε
α
β

Fig.1
Fig.1 f z f z
(2) Practical surface roughness
In case of practical milling, there are many teeth and natural differences in
levels of edges occur. The maximum difference is called “run out”. (Rp)
In the actual face milling, finished surface roughness, as shown in Fig. 2, is
Rp worse than the single point cutting. If only one tooth is projecting, it will be
similar to the single point shown in Fig. 1 but of a large value substituting
f (ipr) for fz (ipt).
f z (Feed per tooth)
f (Feed per revolution)
Fig.2
Fig.2
Improving surface roughness

Face run out must be minimized and a low feed rate and high speed should
Insert be used. Also, in order to attain good finished surface at high efficiency,
SPCN42ZFR there are the following methods:
Technical Reference (2) Use of TAC super finish mill for finishing.
Body
(1) In case of ordinary TAC mill
Locator
Use wiper insert as shown in the figure at left.
• Use of combination TAC mills with finishing insert such as TFD4400-A
and TFP40001A (ap < 1.0 in).
0.03 ~ 0.08
Fig.3
Fig.3
• Use of TAC supe finish mill for finishing such as NMS cutters and
SFP4000, etc.
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