Page 44 - Die_and_Molds_User_Guide_7861458_2017

b) Starting cutting speed Vc

Exactly as for the indexable endmills, calculation of starting cutting speed Vc for the face mills
rests on equation (1):
Vc = Vo x Ks x Kt

Where: Vc – starting cutting speed
Vo – basic cutting speed
Ks – stability factor (1 if stability is enough and 0.7 for unstable operations)
Kt – tool life factor (Table 8)

Table 9 specifies basic cutting speed Vo as dictated by the workpiece material, the carbide
grade and the type of machining, whilst defining the latter can be done through Tables 6 and 7.
If desired, upon condition that the starting feed was calculated from equation (3) and Table 29,
the type of machining for a face mill more suitable for the operation (when the width of cut
is 60-80% of the mill diameter) or for milling a full slot (100% diameter engagement), can be
taken from Table 31.
Milling Tools

Table 31 Type of Machining: Face Milling*
b/D
h/ap
60% 70% 80% 100%**
1/8 Light-duty (L) Light-duty (L) Light-duty (L) Medium-duty (M)
1/4 Light-duty (L) Medium-duty (M) Medium-duty (M) Medium-duty (M)
1/2 Medium-duty (M) Medium-duty (M) Heavy-duty (H) Heavy-duty (H)
3/4 Heavy-duty (H) Heavy-duty (H) Heavy-duty (H) Heavy-duty (H)
* For starting feed fz in accordance with equation (3)
** Milling full slot
Be aware: milling with a width of cut that is 60%-80% of a mill diameter ensures peak efficiency in face milling
Shoptalk: facing and shouldering
In the art of metal cutting, face milling is often called simply facing, slot milling – slotting, and
shoulder milling, correspondingly - shouldering.

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