KE-750_MAINTE.pdf - 第92页
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 …
3.7.3 Timing detection and tact time of chip rise detection
During production, chip rise detection is performed at the timing after
measurement result is obtained. The measurement result is obtained after
completing the part pick and performing the laser measurement at the same
time as starting of the X/Y axes movement.
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Moves to the scanning height after
LA measurement
Moves upward after pick
Z axis
X-Y
LA measurement
Moves to the mount position
Laser measurement
Chip rise scanning
For the chip rise detection, it takes 38 ms including the time for the Z axis to
move upwards and for the scanning. Therefore, if the distance between the
pick position and the mount position is more than 80 mm, the time for the X-Y
movement becomes longer than time T for the laser measurement and chip rise
detection, and tact time is not extended because the chip rise detection is
included in the X-Y movement.
The minimum distance from the pick point to the
edge of the board is 78 mm, and tact time can
becomes longer only when mounting is made in
the range between 78 mm and 80 mm.
Board
In this case, the tact down time delays:
Pick point
38 ms/chip for 1-head mount,
38/2 = 19 ms/chip for simultaneous 2-head
pick, and
K The minimum distance
between the rear pick
point at the rear fiducial is
also 78 mm.
38/3 = 12.6 ms for simultaneous 3-head
pick.
NOTE:
For alternating pick by 2- to 3-head type, there is no tact time delay because
after the component is picked with the 1st pick head, the laser measurement
and the chip rise detection are performed, and during this time, the component
is picked with the 2nd pick head.
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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