LMT FETTE T18F - Putting into Operation and Setup; Rolling Speed and RPM; Working Feed - Number of Workpiece Rotations

Operating Manual
Tangential Rolling System T18F - T27F
28
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6 Putting into operation and setup
6.1 Rolling speed and RPM
NOTICE
Never use a rolling speed below 20 m/min. Otherwise the material cannot
start to flow.
The rolling speed v should be between 20–60 m/min. For specific work applications,
rolling speeds of up to 100 m/min are also possible.
Tensile strength and breaking elongation of the material:
A higher material tensile strength R
m
requires a smaller rolling speed. We recommend
approx. 20–30 m/min for high material strengths and large forming volumes. In addi-
tion, the rolling speed for materials with a higher breaking elongation A must be set
higher than for smaller elongation values.
Profile form:
In principle, V-threads can be created with a higher rolling speed than trapezoi-
dal threads. Depending on the workpiece profile and existing workpiece RPM,
20–60 m/min is recommended for V-threads. For trapezoidal threads and similar
profiles, 15–30 m/min is recommended.
The estimated value for the rolling speed v is used to calculate the RPM n of the drive
spindle as follows:
n =
1000 · v
________
d
a
· π
[1/min]
The rotational direction (rotating to the left or
right) of the machine spindle is arbitrary.
6.2 Working feed – number of workpiece rotations
With the tangential method, the complete length of the thread or the profile is created
with several workpiece rotations. It is important that the number of workpiece rotations
n
W
is strictly maintained during the rolling process. The rolling process should be
ended within n
W
= 10 … 35 workpiece rotations.
The number of workpiece rotations is dependent on the rolling head size, the thread pitch
P, the thread length L and the tensile strength of the material. In general, the following
applies: the larger the forming operation, the higher the number of workpiece rotations to
be selected. Table 7 lists reference values for medium tensile strength materials.
Calculation example:
Thread M16 x 1.5
Blank diameter d
A
= 15.03 mm
Rolling speed v = 60 m/min
n =
1000 · 60
_________
15.03 · π
1
____
min
= 1270.7
1
____
min
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