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SIPLACE HS-50/HS-60/D4/S-25HM/S-27HM/HF -Series 2 Retrofit instructions for vacuum pump 07/2011 Edition 53 2.7 Final t asks 2.7.1 Check the pre-condi tions for switching on 2 Before switching on make the following checks…
2 Retrofit instructions for vacuum pump SIPLACE HS-50/HS-60/D4/S-25HM/S-27HM/HF-Series
07/2011 Edition
52
The absolute vacuum value in the holding circuit with closed nozzles is generally 30-50 mbar
lower for the vacuum pump than the vacuum value for the Venturi generator in the pickup circuit
(if each are measured with an external gauge on an open nozzle in the pickup circuit and on an
open nozzle in the holding circuit).
The absolute value is, however, not of great significance provided that it is in excess of 800 mbar
in Munich and all the heads have approximately the same value. 2
If these values are not achieved, it is almost always because a hose is not pushed firmly home.
The hose which is not airtight can be quickly detected by simultaneously squashing the hoses and
having a second person press the "Measure vacuum" button in the "Placement and pickup circuit"
field. 2
Checking the flow rate of the holding circuit vacuum system after retrofitting: 2
The correct flow rate can be checked with the vacuum curve.
To do this, SITEST is used to open each segment in the pickup circuit in turn without nozzles
(maximum flow rate) and then rotate the segment into the holding circuit with one star step. 2
Depending on the pump size and the number of machines connected, the vacuum measurement
in the holding circuit shows a decrease in vacuum of approx. 60-90 mbar for each additional open
nozzle. All heads should have similar values. 2
The vacuum could, for instance fall by 360 mbar from 880 to 520mbar if 6 nozzles are open. If
several machines are connected to a pump, the reduction is greater, and if only one machine is
connected, it is smaller. 2
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SIPLACE HS-50/HS-60/D4/S-25HM/S-27HM/HF-Series 2 Retrofit instructions for vacuum pump
07/2011 Edition
53
2.7 Final tasks
2.7.1 Check the pre-conditions for switching on
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Before switching on make the following checks to avoid injury and damage. 2
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Switch on always first the vacuum pump, then the placement machine! 2
Ensure before engaging compressed air, that 2
: all hoses / -connections are connected and allocated correctly.
: the pre-conditions for switching on vacuum pump and placement machine are followed, as
described in the user manual.
2.7.2 Check of holding circuit
2.7.2.1 Check vacuum system of holding circuit for pressure tightness
Vacuum measuring with external pressure measurement tool at the measuring point of the va-
cuum distributor and then an open nozzle at the holding circuit on the placement head. 2
The difference should not be higher than 20-30 mbar, if the system is tight. 2
At vacuum check of holding circuit a different value is possible, if vacuum board has an offset.
Therefore measurements at head an vacuum distributor should be done with the same measuring
tool. 2
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The absolute vacuum value of holding circuit with closed nozzles is lower (30-50 mbar ) with
vacuum pump than with venturi nozzle in pickup circuit (measured with an external measurement
tool at open nozzle in pickup circuit and holding circuit) .
This difference is acceptable, if at a height of 521 m NN (height of System acceptance of Siemens
L&A Munich) at least 800 mbar can be achieved. 2
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2 Retrofit instructions for vacuum pump SIPLACE HS-50/HS-60/D4/S-25HM/S-27HM/HF-Series
07/2011 Edition
54
The reason for not reaching these values mostly is a hose in the area of placement head which is
nit attached till stop position: 2
: Impress all hoses with the hose pliers and repeat the measurement of vacuum.
2.7.2.2 Check of the air flow of the vacuum system holding circuit
The correct air flow can be controlled by means of the vacuum curves: 2
: Remove the nozzles from the placement head (to achieve maximum air flow), open in SITEST
all segments in pickup position one after each other and turn it with star cycle into the holding
circuit.
: The vacuum measurement in the holding circuit shows with every additional opened nozzle a
vacuum decrease of 60 - 90 mbar.
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With six open nozzles the vacuum could reduce, e.g. from 880 mbar to 520 mbar (reduction
360 mbar).
With six C&P placement heads at two placement machines on two vacuum pumps the decrease
is higher, at only one placement machine lower (four or two C&P placement heads). 2
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