Phasing Adjustment - Graco PR70 Operation & Maintenance Manual

Setup

Phasing Adjustment

When the machine executes a shot, materials from
Tank A and Tank B enter the static mixer where they are
mixed and then dispensed. In order for the materials to
mix at the desired ratio, both materials must enter the
static mixer at the same time. The timing of the materi-
als entering the static mixer is dependant on the adjust-
ment of the phase adjustment screw for each piston.
This step assumes the home position is set at zero from
the factory. If the encoder cable has been unplugged
during shipment, the zero point will need to be reset.
See setting home in Appendix A - Homing Pumps.
Prepare Machine
1. Place a waste container under the dispense valve to
catch dispensed material.
2. For an MD2 valve, remove static mixer and install
ratio check nozzle onto valve.
3. For an over/under block, remove the pins and pull
the non drip valves out of the block.
F . 4: Ratio Check Nozzle
IG
4. If necessary, place a stand under the ratio check
nozzle or non drip valves.
5. Enter a small size shot.
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6. Adjust the home position:
This step assumes the home position is set at zero from
the factory. If the encoder cable has been unplugged
during shipment, the zero point will need to be reset.
See setting home in Appendix A - Homing Pumps.
Once the zero point is set and material is loaded into the
pumps, it may be necessary to adjust the zero point so
material begins dispensing at the correct time (phasing).
a. Determine if the home position needs adjusted
in the forward or reverse direction. The zero
point will need adjusted forward if the start sig-
nal is given and material doesn't start dispens-
ing right away. The zero point will need adjusted
toward the reverse position if the start signal is
given and a material spurts out at a high pres-
sure and then the flow levels off.
b. Bump the motor in the correct direction. The
position showing up in the Actual box will
change.
c. Press the set Home Offset button and the
Actual position transfers into the Adjusted posi-
tion.
d. Re-home the pumps.
e. Start a dispense cycle and verify material
begins dispensing at the proper time.
f. Repeat steps b through e as needed.
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