DECAN_S2_Admin(Eng_Ver4.5).pdf - 第180页
7-15 Part Registration Memo Normally , the type of the tim e graph becomes dif f erent by parts. For e xample, in the case of the general re ctangular chips gr e a t er than 1608, the p art s a re very light. Therefor e …
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Advanced Chip Shooter DECAN S2 Administrator’s Guide
until vacuum is off.
Figure7.6 “Place Delay Time” Delay Time during Placement
For example, if the Place, Vac OFF and Blow ON are set to 50, 10 and 10
respectively:
The time required is 50ms from the time the Z axis finishes moving down
for placement until the Z axis begins to move up after all processes are
completed.
The Vac off 10 means that the vacuum will be turned off in 10ms after the
Z axis finishes moving down for placement.
The Blow ON 10 refers to the delay time from the time the Z axis finishes
moving down to the time the Blow On is performed.
Generally, the Blow ON value is set to the time same as the Vac Off time.
7-15
Part Registration
Memo Normally, the type of the time graph becomes different by parts.
For example, in the case of the general rectangular chips greater
than 1608, the parts are very light. Therefore, if the Z-axis moves
up before the vacuum disappears completely, the part may fall to
the PCB when the vacuum disappears while it moves up along
with the head.
In other words, item (3) in the following figure may act as the most
important factor for general rectangular chips.
From many test and experiment results, it was known that the
required time in item (3) was at least 0ms up to 20ms. Since this is
very important, the user must have this in mind.
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Advanced Chip Shooter DECAN S2 Administrator’s Guide
Memo In the case of the QFP for fine pitch parts, when the Z-axis moves
down at high speed to place the part, it may physically collide with
the PCB.
In addition, such impact may shake the PCB slightly and cause the
solder paste to be mashed. Therefore, placing the parts in this manner
may cause the reduction of placement accuracy.
Such situation can be prevented by controlling the Vac off delay time.
That is, the part is held by a vacuum until various external factors are
stabilized, after which the vacuum is turned off after the external
factors disappear to prevent the problem.
The Vac off delay time corresponds to item (1) of the following
figure.
In the case of parts with general pitch, even though the time in the
above item (1) is not considered, it does not have great influence on
the placement accuracy.
However, in the case of parts with fine pitch or those that may cause
the above problem, it may be beneficial to set the time in item (1)
short.
Generally, the Vac off delay time is set to 20~30% of the total delay
time in item (4). Since this is very important, the user must have
this in mind.
<Dump> edit box
During component dumping, the delay time after the head has come down
until the head starts ascending.