Troubleshooting Equipment: Powder Application Issues

• Add powder until feed hopper is filled to proper level

• Manually loosen powder and fluidize with clean dry air
• Check compressed air for oil/water and room for high humidity

• Check bottom of feed hopper for obstructions/oil/water.

• Maintain consistent ratio of virgin to reclaim

• Reduce air pressure to fluid bed

• Check hopper vent for blockage
• Check vents assist for obstructions and correct air supply

• Reduce the amount of reclaim added to virgin powder

• Increase air supply to fluid bed

• Clean membrane, remove any dirt, grease and obstructions.
• Check air supply to ensure it is clean

• Remove all obstructions on the membrane

Compacted powder on membrane

• Manually loosen powder and fluidize with clean dry air

Possible Cause

Solution

Primary filter media blocked

· Clean filter system. Replace filter if necessary

· Check ambient air for excessive moisture

· Check filter air pulse system for correct operation

Final filter blocked

· Check primary filters for powder leakage. Service or replace if necessary

Use of compressed air for booth clean down

· Refer to operating manual for correct cleaning methods

Improper powder gun placement/alignment

· Correct as necessary. Position guns away from booth opening

· Check for proper distance from top of part to the conveyor slot opening

Room air drafts causing powder to drift from booth

· Correct as necessary. Position guns away from booth opening

· Check for proper distance from top of part to the conveyor slot opening

Blocked airflow

· Check air volume control damper adjustments

Possible Cause

Solution

Worn gun parts

· Replace parts as required

Impact fusion build-up

· Check gun parts as required

Delivery air too low

· Check air supply. Increase air for powder feed

Hoses, powder pumps or guns blocked with powder

· Clean hoses, pumps and guns

Reciprocator speed too fast

· Adjust gun cycle time

Possible Cause

Solution

Insufficient air pressure or volume

· Check compressed air supply. Mains air pressure should be a minimum of 80 PSI and
of sufficient volume to supply the system

Hoses kinked, flattened or too long

· Check all powder and air feed lines, straighten and shorten if necessary

Hoses, powder pumps or suction pumps

· Clean hoses, powder pumps and gun components

· Check air supply for moisture and oil contaminants

· Check powder delivery and dilution air settings

· Check coating area, relative humidity and temperature

· Check powder delivery system for leaks check powder delivery hose size for powder
flow

Incorrect feed hopper fluidization

· Adjust fluidization air pressure

· Check fluidization membrane for damage, oil or water contamination

· Check for moisture or oil in the powder

Low powder level

· Add powder to the proper level in the hopper

Possible Cause

Solution

Air pressure too high

· Clean or replace worn parts in pump

· Reduce powder hose length

· Decrease flow rate settings on pumps

Moisture in compressed air

· Check air supply filters/dryers to clean, dry oil-free compressed air

Worn powder pumps or parts

· Replace all worn or damaged parts

Possible Cause

Solution

 Reclaim in-line sieve torn

· Powder or dirt falling in spray booth from conveyors, jigs, or flight bars

· Repair sieve or replace, if necessary

· Clean conveyor regularly before it enters powder booth

· Strip jigs regularly

Contamination from components entering booth

· Check cleaning and pre-treatment system

· Ensure components are clean and dry before entering booth

Contamination from plant air circulated through spray booth

· Isolate and preferable enclose spray booth area

· Keep outside doors closed

· Maintain positive air pressure in coating room

· Do not use silicone based oils or lubricants

· Do not use aerosol sprays containing oil in the booth area

Possible Cause

Solution

Bag or cartridge filters blinding

· Clean or replace bags or cartridge filters

· Check spray booth humidity

· Check reverse air cleaning

Too large an open area in spray booth housing

· Reduce open area. Increased opening reduce booth air velocity

Powder delivery rates too high

· Reduce the number of guns spraying or the amount of powder to each gun

Possible Cause

Solution

High voltage is not providing enough kV at charging electrode

· Check if high voltage is ON. Systematically check electrical continuity from the
voltage source to electrode, including the cable, resistor and fuses.

· Use kV meter and megohmmeter to check condition of multiplier, cable/resistor.

· Clean/replace electrode insulated or damaged by powder build-up or impact fusion

Poor earthing

· Checking earthing from conveyor rail through hanger to part. Contact areas must be
free of powder build-up, grease and other insulators

Powder delivery too high

· Reduce powder feed until material is adequately charged

Excessive moisture in air supply

· The charge can be dissipated by moist air, humidity must be controlled

Powder too fine

· Maintain consistent ratio of virgin to reclaim 3:1

· Check particle size of virgin powder

Powder delivery air too high. Powder blowing past component

· Turn down air setting or move gun position further away from component

Possible Cause

Solution

Powder delivery too low

· Increase powder flow rate air setting

· Replace all worn or damaged parts

Poor earthing

· Check all earthing point contacts. Clean if necessary

Incorrect spray pattern or nozzle

· Adjust spray pattern or select a more suitable nozzle, i.e. flat-spray, deflector or
pin-point

Poor gun placement

· Adjust gun position so powder cloud has a direct path to recess area

Voltage too high

· Decrease voltage level

Powder delivery velocity too high

· Decrease voltage level

Powder delivery velocity too high

· Decrease flow rate and/or atomizing settings so powder air stream does not blow out of
corners