Troubleshooting to overall electrostatic coating operation

Problem, Cause and Remedy

PROBLEMCAUSEREMEDY
Poor charging-inadequate powder build or wrap on partHigh-voltage source not providing enough KV at charging electrode or grid.Check high voltage source is on.
Systematically check electrical continuity from voltage source to electrode (grid) including cable, resistors and fuses.
Replace missing or broken electrode (grid).
Clean electrode (grid) insulated by powder build or impact fusion.
Poor groundCheck ground from conveyor rail (or rub bar when used) through hanger to part. All contact areas must be free of powder build, heavy grease and other insulating material.
Powder delivery (feed) is too highTurn down powder feed until all material passing through charging corona (field) is adequately charged
Excessive moisture in powder booth airMoisture in humid air will tend to dissipate humidity in the powder spray area
Powder too fineToo much reclaim added to virgin powder.
Virgin powder pulverized too fine by manufacturer.
Powder type or formulaSome resin types charge better than others and some formulas are designed for thin film application.
Check with your powder supplier.
Powder delivery air too high Powder blowing by part. Turn down air setting or move gun position farther away from Part
Poor penetration-powder will not coat Faraday Cage areas(holes, grooves, channels, inside corners, and recesses).Powder delivery too lowTurn up powder delivery air setting.
Use gun barrel extension.
Poor groundCheck ground
Powder spray pattern too wideSelect smaller deflector or use suitable slotted barrel and cover. (Consult your equipment supplier.)
Voltage too highTurn voltage setting down so powder builds on part edges and leading surfaces do not repel powder from corner.
Powder delivery velocity too highTurn air settings down so powder/air stream does not blow powder out of corners.
Poor gun placementAdjust gun position so powder cloud has a direct path to recess area.
Powder too fineToo much reclaim added to virgin powder.
Virgin powder pulverized too fine by manufacturer.
Back charging-powder layers are repelled from part in spots.Voltage too highTurn down voltage setting.
Gun positioned too close to Part. Change gun placement away from part.
Poor groundCheck ground
Powder too fineToo much reclaim added to virgin powder.
Virgin powder pulverized too fine by manufacturer.
Powder picks up a random charge through powder or in fluid path. Reverse charging usually through reclaim systemPowder booth air too dryAdjust powder spray area humidity. See chart for optimum conditions
Poor delivery and/or reclaim usually through equipment ground.Provide ground for all equipment
Powder feed spurting or slugging-interrupted powder feedInsufficient air pressure or volumeCheck air supply. Air supply piping to equipment is large enough. Enough air volume when other equipment such as reverse air cleaning in reclaim housing pulses, air pressure to powder feed does not drop
Hoses kinked, flattened, or too long. Check powder feed hoses
Hoses, pump venturis , or guns clogged with powderClean hoses, venturis, and guns.
Check air supply for moisture that causes powder compaction.
Check powder free flowing properties.
Check spray booth air humidity.
Check powder supply for contamination.
Check reclaim sieve
Poor spray pattern-not a symmetrical powder cloud (not applicable when using special deflectors for desired effect) Worn E/S gun parts.Replace worn feed tubes, orifices, deflectors, and covers
Impact fusion build.
Delivery (feed) air too low
Clean gun parts as needed.
Check air supply. Increase air for powder feed.
Hoses, venturis, or gun blocked with powderClean hoses, venturis, and guns
Troubleshooting to overall electrostatic powder coating operation