KE-750_MAINTE.pdf - 第89页
The constant 1.25 is obtained as follows: The size of a 1005 type resistor is t = 0.35 mm and W = 0.5 mm. So, the height for horizontal rise detection is about 1.25 × t when the middle of the space shown in the figure be…
3.7 Chip Rise Detection
3.7.1 Outline
After picking the part, chip rise detection is performed immediately after the
laser measurement which is started together with the movement of X/Y axes.
For the chip rise detection, the Z axis is moved to the height obtained from the
thickness of the part being picked, and whether the part is picked is scanned
with the laser. Whether to perform the chip rise detection can be set using the
part data or the setup data. When the chip rise detection is performed, there
may be a delay in the cycle time depending on the distance of the X/Y
movement or the method of pick.
3.7.2 Detection
Chip rise detection is mainly applied to square chip parts and Melf parts.
Scanning for detection is performed by adjusting the laser height using the
value which is the part thickness t entered as the part data multiplied by a
constant 1.25.
Part size
Horizontal
rise
Normal pick Vertical rise Slant rise
Laser height
When part pick is performed normally, Status 64 (No Component) is returned as
data. When a chip rise occurs, the laser is obstructed with the part, and a
status other than 64 is returned. In this case, the part is rejected being
detected as chip rise.
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The constant 1.25 is obtained as follows:
The size of a 1005 type resistor is t = 0.35 mm and W = 0.5 mm. So, the
height for horizontal rise detection is about 1.25 × t when the middle of the
space shown in the figure below is scanned.
(0.35 + 0.5)/2≒1.25 × 0.35
where: t is 0.35, and W is 0.5.
Normal pick
Horizontal
rise pick
Laser scanning height
Scanning at the middle of the space
(1) If the entered value of the part height is different from the actual part
dimensions, the part will be rejected even when it is normally picked. For
2125R type, t = 0.6 mm, and scanning height for the chip rise is 0.6 × 1.25
= 0.75.
Laser scanning height
0.15 mm (Space)
If an incorrect value of 0.4 mm has been entered for the part height, the
scanning height is 0.5 mm (0.4 × 1.25), and the part will be rejected even
when pick is performed normally. In this case, measure the part height
by automatic measurement, and enter the correct value.
(2) If the laser height of the nozzle is incorrect, the part will be rejected even
when pick is performed normally. If the laser height of the nozzle (Set-up
data) is set below the correct position, the chip normally picked will be
detected at the laser scanning height.
Laser scanning height
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The laser height of the
nozzle is set too low.
Even when the nozzle moved up by 1.25 t,
the chip will be detected by the laser
In this case, obtain the laser sensor height of each head in the
maintenance mode, and reinstall the nozzle height by nozzle allocation of
the Set-up data.
(3) The part may be rejected depending on the pick condition. For example,
for the 2125R type, the space between the bottom surface of the part and
the scanning height is 0.15 mm, and if the part is picked inclined, it may be
rejected.
Scanning height
In this case, there is a problem with the pick position, and it shall be
reviewed. Because the setting value for the height of the chip rise
detection can be changed with the part data of each part, a safer setting
can be made for some part size.
Normal pick Horizontal rise pick
Laser scanning
height
Scanning at the middle of the space
The default value obtained with the above part size is 1.25 × t = 0.75 mm.
However, when the laser height is set at the middle of the space between
the normal pick position and the horizontal rise pick position, it it (t + W)/2
= (0.6 + 1.25)/2 = 0.925 mm. Accordingly, if this part is rejected when
picked, it is effective to change the detection height to 0.925 mm.
Note that how to obtain (t + W)/2 cannot be applied to all types of parts.
For the parts which are of the same thickness (t) and width (W) (e.g.
1608C and 1005C), (t + W)/2 = t applies, and they can be rejected even
when normally picked.
(For 1608C, T = 0.8 mm and W = 0.8 mm.
Therefore, chip rise detection height H = (0.8 + 0.8)/2 = 0.8 mm.)
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