OBSOLETE
21-37
Issued 7/96
8
Troubleshooting
Figure 2 shows some common spray pattern faults.
Troubleshooting procedures for these and other
common film-build faults are listed in Table 3. If you
cannot solve your problem with the information given
here, contact your local Nordson representative or
distributor for help.
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1
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7
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2137002A
Fig. 2 Common spray pattern fault
1. Blown pattern
2. Heavy bottom pattern
3. Heavy top pattern
4. Heavy left side pattern
5. Heavy right side pattern
6. Heavy center pattern
7. Spitting pattern
Table 3 Troubleshooting Procedures
Spray Pattern/
Film Faults
Corrective Action
Blown pattern
Reduce pattern/horn air; increase coating material pressure.
Heavy top or
Heavy bottom
Rotate air cap and trigger spray gun; if problem exists, clean air cap; if problem does not
exist, clean fluid tip or replace air cap; change coating material mixture, if necessary.
Heavy left side or
Heavy right side
Rotate air cap and trigger spray gun; if problem exists, clean air cap; if problem does not
exist, clean fluid tip or replace air cap; change coating material mixture, if necessary.
Heavy center
Increase atomizing air, increase pattern/horn air, or reduce coating material viscosity.
Spitting
Purge air bubbles in fluid line; adjust puller; raise atomizing air and reduce fluid pressure;
increase pattern/horn air; raise coating material temperature.
Runs and sags
Purge air bubbles in fluid line; adjust puller; raise atomizing air and reduce fluid pressure;
move farther from substrate, increase pattern/horn air; raise coating material temperature.
Dry spray
Reduce atomizing air; reduce pattern air; change coating material mixture.
Poor or no wrap
Check electrostatic power supply; clean spray gun; remove water from supply air; check
substrate ground; check spray gun for internal leakage.
Poor coverage in
recesses
Raise atomizing air and coating material pressure; reduce electrostatic power supply
voltage; move closer to substrate.
1996 Nordson Corporation
Nordson, the Nordson logo and Iso-Flo are registered trademarks of Nordson Corporation.
