KE-750_MAINTE.pdf - 第93页
3.8 Vacuum and Blow timing When Mounting Parts 3.8.1 Timing on KE-730/740 When blow operation is performed duri ng part mount on KE- 730/740, the nozzle pressure becomes positive or negative at the same timing of mountin…
Timing of chip rise ON/OFF when the distance from pick to mount is 78 mm
(minimum)
[Chip rise OFF]
3-point simultaneous pick
Waiting time for X/Y until chip rise detection
is complete. (In the example above q,
there is no waiting time.)
[Chip rise ON]
Movement of the Z
axis for chip rise
detection
Laser measurement
Laser scanning for chip rise detection
When the distance X-Y movement exceeds 80 mm, there is no X/Y waiting time.
[Chip rise ON]
There is no waiting time as in the example w above.
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3.8 Vacuum and Blow timing When Mounting Parts
3.8.1 Timing on KE-730/740
When blow operation is performed during part mount on KE-730/740, the nozzle
pressure becomes positive or negative at the same timing of mounting.
Therefore, the following may occur when there is an offset in the mount timing.
The part is picked at the negative pressure.
The part immediately after mount is rotated at positive pressure.
The parts those placed around are blown away at positive pressure.
For this reason, mounting is performed not using vacuum destruction by blow
but giving the time for the pressure to naturally recover to normal room
atmosphere. When recover the pressure not using blow but turning the
vacuum off only, the pressure inside the nozzle becomes normal room
atmosphere in 70 ms (for KE-730/740) as shown in Figure 1.
Negative pressure
Atmosphere
Positive pressure
Vacuum off
Figure 1
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Figures 2 and 3 show the vacuum blow timing when mounting on KE-730/740.
For chip parts, the vacuum is set off 70 ms before the nozzle (Z axis) moves
down, and the part is mounted being held by the remaining pressure (negative
pressure) in the pipe. For heavy parts, the vacuum is set off 40 ms (or 20 ms)
before the downward movement is complete, and the nozzle is held for 30 ms
(or 50 ms) above the board. Then, the nozzle is moved up after vacuum
pressure is released.
Square chip parts
Z axis
Vacuum
Blow
Figure 2
For Melf, aluminum electrolytic capacitor, network resistor, trimmer, SOT, SOJ, SOP, and
PLCC
Z axis
Vacuum
Blow
For QFP, TSOP, BGA, connector, and socket
Figure 3
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