Graco PR70 Operation & Maintenance Manual page 32

Setup
F . 6: Ratio Beam Snap Ring
IG
j. Tighten the socket head cap screw (203) on the
adjustment clevis.
5. Phase the machine. See Phasing Adjustment,
page 28.
Perform Weight Ratio Check Shot
6. Install ratio check nozzle onto dispense valve (MD2
valve only).
F . 7: Ratio Check Nozzle
IG
7. Place a waste container under the dispense valve to
capture any dispensed material.
8. Go to shot mode.
9. Select a shot.
10. Press the cycle pumps button or the foot-switch to
dispense material.
11. Discard the shot.
12. Label one scale as "A" and a second scale as "B".
13. Label one new container as "A" and a second new
container as "B".
14. Place container "A" on scale "A" and tare the scale.
Place container "B" on scale "B" and tare the scale.
32
206
0.5 mm gap
205
ti12630a
ti12392a
15. Place container "A" under the A material output of
the ratio check nozzle. Place container "B" under
the B material output of the ratio check nozzle.
16. Press the pump cycle button or the foot-switch to
dispense material.
17. Place container "A" on scale "A" and note the
weight. Place container "B" on scale "B" and note
the weight.
18. Divide the weight of container "A" by the weight of
container "B" to get the weight ratio of the dispensed
materials.
19. Repeat steps 13 through 18 at least two more times
for an overall total of at least three ratio check shots,
or repeat as needed.
20. If the average A to B ratio of the dispensed materi-
als is too high or two low, adjust the mechanical
ratio arm as required by repeating steps 4 through
19 until the dispensing ratio is correct.
• If the A to B ratio is too high, turn the ratio
adjustment knob (201) counterclockwise to
adjust the mechanical ratio arm towards the 1:1
position.
• If the A to B ratio is too low, turn the ratio adjust-
ment knob (201) clockwise to adjust the
mechanical ratio arm towards the 2:1 position.
Secure Dispensing Ratio
21. Once the ratio check shots confirm the A to B dis-
pensing ratio is correct, tighten all screws holding
the ratio beam (202) in place.
a. Tighten the socket head cap screws (203) hold-
ing the ratio beam (202) in place to 140 in-lb
(15.8 N•m).
b. Tighten the hex head cap screw (204) holding
the ratio beam guide (205) in place to 350 in-lb
(39.5 N•m).
Prepare Machine for Operation
22. Remove ratio check nozzle and install static mixer
or night cap as necessary.
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