80S-15贴片机.pdf - 第313页
SIPLACE 80S/F/G Service Manual 9 Revolver Head Edition 04/97 9 - 29 Fig. 9. 5.6 Calculation of the vacuum values for the SIPLACE 80S/F and revolver head How to calculate vacuum values for the turret head Siplace 80S &…
9 Revolver Head SIPLACE 80S/F/G Service Manual
Edition 04/97
9 - 28
The following vacuum values are determined:
1. Checking the Vacuum in the Holding Circuit
A check is made as to whether the vacuum value of the holding circuit is better than the specified threshold
value.
2. Vacuum value "Segment sealed" in the pick-up and placement circuit
This value is determined for every segment in revolver head station 1. Firstly the value is determined for
each of the two positions of the sealing piston: segment opened and segment closed. Next, the two values
are compared and a decision is made as to whether the segment must be closed. These two values pro-
vide the "measured vacuum clearance between open and closed segment" (see Fig. 9.5.6).
3. Vacuum value "Component picked up" with large nozzles in the pick-up and placement circuit
This value is determined in revolver head station 1 for each segment with the corresponding nozzle. The
sealing piston is retracted: in other words, the segment is opened. On the basis of this measurement a
threshold value "Maximum vacuum value for the open segment" is defined (see Fig. 9.5.6).
4. Vacuum value "good and bad nozzle contact" for components in the ejection circuit
In revolver head station 3 (ejection circuit) the vacuum values are determined for normal nozzle sizes for
each segment with the segment open and closed. It is then decided whether the segment must be closed.
A check is made at the same time whether the clearance values with the segment open and closed exceed
the minimum value specified by the line computer. These values are used in turn to calculate the threshold
values for "Good and bad nozzle contact" and added to the MA data (see Fig. 9.5.6).
SIPLACE 80S/F/G Service Manual 9 Revolver Head
Edition 04/97
9 - 29
Fig. 9.5.6 Calculation of the vacuum values for the SIPLACE 80S/F and revolver head
How to calculate vacuum values for the turret head
Siplace 80S & 80F
Vacuum [ % ]
Closed
tight
Open
Vacuum separation
measured between open
and closed segment
Vacuum limit for closed segment
with permissible leakiness
Vacuum limit for open segment
with good nozzle contact
Vacuum limit for open segment
with poor nozzle contact
Maximum permissible value
for vacuum for open segment
Vacuum limit for open segment
with permissible nozzle contamination
... Vacuum value measured
when segment is closed.
Minimum separation of
vacuum values with
open and closed segment
Vacuum value
measured when the
segment is open
9 Revolver Head SIPLACE 80S/F/G Service Manual
Edition 04/97
9 - 30
The vacuum threshold value "Good nozzle contact" lies below the maximum vacuum value while the value
"Bad nozzle contact" lies above the minimum permissible vacuum value. At the same time the values
"Vacuum limit value for permissible leakages while segment closed" and "Vacuum threshold value for the
permissible contamination of the nozzle when the segment is open" are entered.
NOTE
If a nozzle is defined in the machine data file AKTUELL.MA for a segment as invalid or not present, no vac-
uum measurement will be made at that segment. This measurement is first activated in the nozzle change
menu during setting up.
9.5.4.2 Monitoring the Vacuum during Pick-Up and Placement Cycle
In the monitoring of the vacuum the actual values of the vacuum are measured during the pick-up and place-
ment cycle of the revolver head and compared with the values specified by the program or computer specified
- and which had been determined in the reference run.
If the specified values are not achieved, then the conclusion appropriate in each case will be drawn, such as
"Warning", "Closure of segment" or "Fatal error messages".
The vacuum obtaining in each case is measured by the pressure sensors of the placement and ejection
circuits as follows:
1. Vacuum sensor of the placement circuit "Component picked up / not picked up" (pick-up cycle)
"Component present / not present" (placement cycle)
"Component picked up / not picked up", measurement during the pick-up cycle
The sz axis positions itself with sensor stop upon the component which is to be picked up. Only after the end
message of the sz axis for "Nozzle is positioned on the component" is received is the nozzle opened and the
component sucked up. The vacuum is measured after the component has been picked up and after the sz
axis has moved up in revolver head position "1".
If the threshold value "good" or "bad nozzle contact" is not achieved this means that either there is no compo-
nent at the nozzle or too much air is being sucked in at the nozzle due to an incorrectly positioned component.
If no component has been picked up, the revolver head cycles the segment on to the reject station. The
revolver head here moves over the collecting container and ejects the incorrectly positioned component. The
sealing piston closes the segment. Next, the vacuum test is carried out for permissible airtightness and con-
tamination (optimized vacuum sequence). The revolver head cycles on to the pick-up and placement station
and tries once more to pick up a component. If this attempt also fails, this will be added to the "Not done" list.
If access to a component on the conveyor is unsuccessful three times in succession the conveyor is set to
"Track empty" and the track error displayed on the screen. The placement sequence will however only be
halted when the PCB is completely assembled with the exception of the missing components.