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14. Cutting speed
14.1. Choice of the cutting speed
The following values are approximate values which are referred to as a basis for
sharp threads.
Crucial factors for the choice of the cutting speed are apart from the workpiece, the
strength of the die clamping and the unclamping- and the machining length.
In general, the upper values can only be achieved with inner coolant supply.
Material
Machining steel
Construction steel up to 500 N/m²
Construction steel over 500 N/m²
High- alloyed steel
Annealed cast iron
Grey cast iron
Short- chipping brass
Long- chipping brass
Bronze
Copper
Aluminium alloy
14.2. Calculation
The cutting speed is calculated according to this formula:
= d ∙ π ∙ n
v
c
1000
v
= cutting speed [m /min.]
c
d = thread diameter [mm]
n = rotation speed [min
Referring to the given cutting speed the rotation speed is calculated according to this
formula:
n=
vc ∙ 1000
d ∙ π
14.3. Choice of the infeed
The infeed has to correspond always with the lead of the thread to be cut. That means
an infeed of f =1, 00 mm has to be set for a thread M 12 x 1.
An infeed of 25, 4 mm /14 = 1,814 mm has to be set accordingly for an UNF thread
7/8-14 with a lead of 14 movements/ inch.
Cutting speed m/min.
15 - 50
10 - 25
5 - 15
5 - 10
10 - 30
10 - 25
30 - 60
30 - 50
20 - 50
15 - 50
20 - 60
]
-1
Cutting speed
Table 4:
Cutting speed
Operating Manual ZR 26-I
29
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