00195193-02 SG D4 FSE en (1).pdf - 第268页
Modular conveyor Description of the functions Checking th e PCB position on the conveyor sections S tudent Guide SIPLACE D4 (FSE) Modular conveyor EN 09/2006 252 The conveyor side is mechanica lly connected to t he dri…
Modular conveyor
General Description of the functions
Student Guide SIPLACE D4 (FSE)
EN 09/2006 Modular conveyor
251
11 Modular conveyor
11.1 Description of the functions
11.1.1 General
In the Processing Area (PA1 or PA2), the PCB board will be clamped from the bottom side against the
fixed holder on the conveyor system. Therfore, the distance between the top of the PCB board and the
placement head will always be the same for every PCB board, regardless of the PCB thickness. This
has the following advantages:
The placement rate is also no longer dependent on the PCB board thickness.
Furthermore, the fiducial recognition can be optimized,
because the distance between the PCB and the PCB camera is always the same. The PCB fiducial
shape is optimally imaged on the CCD chip of the PCB camera.
The PCB transport is configured in the machine so that the C&P12 head can place components up to a
maximum height of 6 mm.
The machine height can be selected to allow the machines to be integrated into lines with a transport
height of 830, 900, 930 or 950 mm. Communication between the PCB conveyors of the different
machines is provided with the help of a SMEMA or (optionally) SIEMENS interface.
Movement of the PCBs in the input conveyor, intermediate conveyor and output conveyor is monitored
and controlled with light barriers consisting of a transmitter module and a receiver module:
When the PCB reaches the placement area, the PCB is detected by a light barrier and the speed of
the conveyor belt is reduced.
About 100 ms later, a laser beam recognizes the front edge of the slowly approaching board, the
board is stopped and clamped into place from below.
11.1.2 Clamping
The PCB is lifted for placement of components and pressed up against the PCB clamping rail. When the
lifting table rises the PCB and the complete conveyor drive unit is lifted up to the clamping position.
Therefore the placement level is constant and independent of the thickness of the PCB.
PCBs up to 368 mm long are clamped in the appropriate placement areas. Clamping does not take place
on the input and output conveyor. PCBs which are longer than 368 mm (max. 610mm) lie on the belts
up to a length of 390 mm, but are only supported by the lifting table in the placement area.
11.1.3 Width adjustment
The width is adjusted by means of a motor as programmed. With the dual conveyor, different widths are
possible for the two conveyor tracks. The width adjustment uses a stepping motor, meaning that the new
PCB width can be set independently of other machine components.
The conveyor sides are fixed by means of a clamping unit on a steel strip.
The PCB width is adjusted via two adjustment units, installed under the input or output conveyors.
The stepping motor moves the two adjustment units synchronously through the use of ball screws
and a toothed belt.
To adjust the board width, the two adjustment units are positioned under the relevant conveyor side.
The precise position is detected by a BERO on the driver.
Modular conveyor
Description of the functions Checking the PCB position on the conveyor sections
Student Guide SIPLACE D4 (FSE)
Modular conveyor EN 09/2006
252
The conveyor side is mechanically connected to the driver by extending the pneumatically-actuated
fixing pins. This disables the clamping of the conveyor side (at the steel strip).
Once the new PCB width is reached the fixing pins of the driver are retracted once more. The
conveyor side is clamped again.
On the dual conveyor, the widths of the conveyor tracks have to be set one after the other (just one drive
for both conveyor tracks). The maximum and minimum PCB widths are protected by limit switches. If the
two conveyor sides of a conveyor lane are not parallel, this is automatically corrected during the width
adjustment. The two adjustment units are moved under the fixed conveyor side and the other conveyor
side is adjusted. Adjustment relates to the center point between the positions of the two adjustment units.
The adjustment unit which reaches its position under the flexible side first, locks the side. The process
continues until the second adjustment unit has reached its position and has also locked the flexible
conveyor side. The position of the conveyor side has now been recorded, fixed with the adjustment unit
and is ready to set the correct board width.
The flexible dual conveyor can also be used as a single conveyor by closing up track 2 (max. PCB format
368x380mm).
11.1.4 Checking the PCB position on the conveyor sections
The positions of the PCBs is identified using light barriers (transmitter modules and receiver modules).
The transmitter light barriers are positioned below the transport belts. They are directed past the
transport belt to the opposite conveyor side to the receiver above the belt.
The signal from the light barriers stops PCBs in the input conveyors, intermediate conveyors and output
conveyors. These three light barriers can be assembled into four different positions to recognize also
"irregular" circuit boards (PCB with cutouts).
In the placement area, the light barrier triggers the deceleration or braking procedure via the DC
motors. A time period has already been set in the software for slow board approach towards the laser
light barrier.
A PCB moving control check the start- and arrival time at the conveyors. This is necessary because of
the PCB-information (bad mark -, PCB recognition) we transfer from PA1 to PA2. The operator is not
allowed to remove PCB’s from the intermediate conveyor.
11.1.5 Stopping the PCB
The PCB in the placement area is recognized by a laser light barrier. The laser beam looks for the front
edge of the board and stops it, as a result there is no shock against the stopper. The positioning accuracy
of the clamped PCB is +/-0.5 mm -precise enough for PCB recognition.
11.1.6 "Long Board" option
In this option, the "long board" is clamped down twice in placement area 2, so that the placement head
(C&P head) can reach the whole board.
The hardware is mounted in the output conveyor:
Mechanical stopper
Light barrier
With this option the standard conveyor light barriers and lasers remain active!
Modular conveyor
"Alignment Pin" option Description of the functions
Student Guide SIPLACE D4 (FSE)
EN 09/2006 Modular conveyor
253
11.1.7 "Alignment Pin" option
This option is for unfavorable lenght/width relationship, for cut outs at the leading edge at a PCB board
or for wide and short boards. (This also allow to combine the conveyor systems when the PCB have a
steped leading edge.) Mechanical stopper pins are mounted on a flexible conveyor side at the lifting
table. This option can be enabled or disabled with a switch. The lifting table move up, so that the top of
the pin is at the same height as the board. The laser recognize the PCB board and the conveyor stops
after a defined time and the clamping is completed. The clearance under the PCB board is reduced to
25mm.
11.1.8 Lifting table
Depending on the version (single/dual conveyor), one or two independent lifting tables are used in each
placement area. The lifting table drive works indirectly via a pneumatic cylinder controlled by a 5/3-way
valve. PCB‘s of different thickness will automatically be compensated for. The PCB is guided in the Z
direction at four points on the lifting table plate. The lifting path is determined via a distance measuring
system.
The top position of the lifting table is identified by the position measuring system and a fork light barrier
for lane A and B. The top position of the lifting table and the correct clamping of the board are checked
in current mode via the conveyor motors. The lowest lifting table position is detected by the incremental
measuring system and an end position BERO on the pneumatic cylinder. The default clearance under
the PCB is 40 mm.
If you use a dual conveyor as an single conveyor you must couple both lifting tables.
11.1.9 Firmware functions
Transporting, clamping, temporarily storing the PCBs, positioning the PCB using a laser light barrier,
mechanical stopper for long PCBs as an option
Single functions for controlling the conveyor
Adjusting the conveyor width
Controlling the inputs/outputs (using the Sitest program)
Downloading the firmware via SITEST
Setting the conveyor parameters (conveyor speed) in Sitest
Synchronous transport mode
Calibrating the conveyor sides (SITEST function)
Saving the machine conveyor data
NOTE:
The red, 74 mm board supports, previously used for S20, F4, S25HM, S27HM,
F5HM, HS50, HS50+, are not suitable for use in HS60, HF, X or D machines.
Use the black 94 mm board supports for HS60, HF, X and D machines.