Shaper Cutting Speed, Feed and Depth of Cut
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Shaper Cutting Speed, Feed and Depth of Cut
Shaper Cutting Speed, Feed and Depth of Cut - The cutting speed at which metal may be removed with a shaper depends principally on:
(i) The type of material being cut,
(ii) The amount of material being removed at each cut,
(iii) The kind of tool material e.g. high speed steel of cast alloy, and
(iv)The rigidity of the machine.
Given
below
are
the
values
of
cutting
speed
for
shaping
different,
metals/alloys
using
high
speed
steel
cutting
tool.
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Cutting speed on shaper may be defined as the average speed of tool during the cutting stroke and depends primarily on the, number of ram strokes per minute and the length of the stroke.
Let L = length of stroke in metres.
N = Number of strokes per minute
Thus the distance moved by the shaper tool per minute
=LN metres
Since shaper works only during the cutting stroke and does no cutting during the return or idle stroke, the ratio of cutting speed to return speed enters into the calculation, as it is necessary 10 determine what proportion of time the cutting tool is , working. Thus with the ratio
Cutting stroke / Return stroke = 3/2, the Cutting time / Total time = 3/5
From (a) and (b) We find that the time actually spent in cutting
LN-m
is
only
3/5
min
and
not
I
min
because
no
cutting
is
done
during
the
return
or,
idle
stroke.
Thus
in
3/5
minutes
the
tool
cuts
LN
metres
length,
and
therefore
in
I
minute
the
tool
will
cut:
5LN/ 3 metres.
Hence the shaper cutting speed
C.S. = 1.67 LN metres
From (c), the number of strokes/minute for a desired cutting speed is then
N = C.S / 1.67 L = 0.6 C.S/ L
The total number of strokes required to complete a job,
S1 = W/F
where W is the width of the workpiece in mm
F is the feed in mm,
The total time required to complete a job
T= St/N minutes
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