Delta ASDA-A3 Series User Manual page 509

Motion Control
For E-Cam curves used in the rotary shear applications, apart from the requirements of
synchronous speed and fixed length, the speed has to be stable. The arc length between cutter
ends (Figure 7.3.7.8) and the cutting length proportion will determine the speed variation. The
larger the value, the greater the variation. If each arc length between cutters is longer than the
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cutting length, the motor speed is faster than the master axis before entering the synchronous
speed zone. So, the motor needs to decelerate to the master axis speed, as shown in Figure
7.3.7.5 (a). If the arc length between cutters is shorter than the cutting length, the motor speed
is slower than the master axis before entering the synchronous speed zone. Therefore, the
motor needs to accelerate to the master axis speed, as shown in Figure 7.3.7.5 (b).
(a) Arc length between cutter ends > cutting length
Figure 7.3.7.5 Correlations between the cutting length, speed, and arc length between cutter ends
You can adjust the cutting length by changing the cutter rotation speed. However, the larger the
synchronous speed zone, the less flexibility to adjust the cutting length. As shown in Figure
7.3.7.6, the cutting length is the same, meaning the rotation distances of the pointed cutter and
wide blade cutter are the same (measure of the speed curve area). When you use a wide blade
cutter, the non-synchronous speed zone is larger and requires an abrupt acceleration or
deceleration, which may easily make the motor reach the maximum torque limit. When the
cutter cannot cut the material with a shorter length due to the cutter speed or the maximum
current limit, increase the cutter number to shorten the operation distance per cutting, making
the cutter slower and the current output lower.
Speed
(small synchronous speed zone)
7-106
Speed curve
Position curve
Material
feeding axis
Cutting axis
speed
Material
feeding axis
speed
(a) Pointed cutter
Figure 7.3.7.6 Size of the synchronous speed zone and motor speed
speed
(b) Arc length between cutter ends < cutting length
Speed
Time
(b) Wide blade cutter
(large synchronous speed zone)
ASDA-A3
Material
feeding axis
speed
Position curve
Speed curve
Cutting axis
speed
Material
feeding axis
speed
Time