88242361-04-01 Vol 1 DEK TQ TECHNICAL REFERENCE (1).pdfPDFA.pdf - 第126页

8 SQUEEGEE MODULE 8.1 OVERVIEW 126 TECHNICAL REFERENCE MANUAL DEK TQ 04/2021 8.1.2.2 Purpose The PRHM monitors the amount of paste on the stencil during the rearward print stroke. This is achieved by using a laser beam t…

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8 SQUEEGEE MODULE
8.1 OVERVIEW
TECHNICAL REFERENCE MANUAL DEK TQ 04/2021 125
8.1.2 Paste Roll Height Monitor (PRHM)
8.1.2.1 Laser Safety
CAUTION
RADIATION. RISK OF INJURY TO THE EYES DUE TO LASER LIGHT BEING
PRESENT IN THE VICINITY OF THE LABEL. DO NOT LOOK AT THE LIGHT
SOURCE OR REFLECTIONS FROM A SURFACE.
CAUTION
EQUIPMENT SERVICING. THE LASER DOES NOT CONTAIN USER
SERVICEABLE PARTS. OPENING THE UNIT COULD CAUSE MIS-ALIGNMENT
OF THE LASER, THIS MAY MAKE THE EQUIPMENT DANGEROUS TO
OPERATE.
CAUTION
LASER CONTROLS AND ADJUSTMENTS. USE OF CONTROLS OR
ADJUSTMENTS OR PERFORMANCE OF PROCEDURES OTHER THAN THOSE
SPECIFIED HEREIN MAY RESULT IN HAZARDOUS RADIATION EXPOSURE.
This module uses a Class 1 laser light source which in normal use does not represent a significant
risk of eye injury. When switched ON, the user should not stare directly into the laser light or at re-
flections from the light targeted surfaces for long periods.
8 SQUEEGEE MODULE
8.1 OVERVIEW
126 TECHNICAL REFERENCE MANUAL DEK TQ 04/2021
8.1.2.2 Purpose
The PRHM monitors the amount of paste on the stencil during the rearward print stroke. This is
achieved by using a laser beam to measure the top of the paste roll. As the software knows the dis-
tance to the stencil, it can calculate the height of the paste roll.
The system can:
●
Suspend print if too much paste is detected
●
Suspend print if too little paste is detected
●
Warn when a user defined lower limit is reached
If, combined with an automatic paste dispenser it can also add paste, independent of pre-defined
paste management settings (see Note below)
NOTE
If a PRHM is fitted and enabled and a paste dispenser is fitted and enabled the dispense rate para-
meters are ignored. PRHM determines when paste is dispensed by the height set in the minimum
paste warning parameter.
8.1.2.3 PRHM Assembly
The PRHM assembly consists of a laser photoelectric sensor mounted on the squeegee mechan-
ism. The laser is angled allowing the sensor to project the laser beam between the squeegees to
the paste roll.
Laser
1
IEC 60825-1:2014
3
4
1
2
View on Right Hand Side of Squeegee Mechanism
1 Laser Photoelectric Sensor 3 Laser Emitter
2 Paste Roll 4 Laser Receiver
8 SQUEEGEE MODULE
8.1 OVERVIEW
TECHNICAL REFERENCE MANUAL DEK TQ 04/2021 127
8.1.3 Paste Deflectors
Paste deflectors may be used to keep the print medium in front of the squeegees.
1 Paste Deflector Securing Screws 3 Squeegee
2 Paste Deflectors
8.1.4 Squeegee Drip Tray
1 Air Inlet to Extend Drip Tray 4 Drip Tray
2 Drip Tray Pneumatic Actuator 5 Air Inlet to Retract Drip Tray
3 Rubber Bumper Stop 6 Drip Tray Retracted Sensor
The squeegee drip tray mechanism is secured below the print carriage and behind the squeegee
mechanism. The drip tray’s pneumatic actuator extends the drip tray below the squeegees to pre-
vent print medium from dripping onto the stencil during print carriage initialisation or auto stencil
loading. Magnets hold the drip tray in place and can easily be unhooked for easy cleaning.
There are two sizes of drip tray:
●
460mm
●
360mm