POWDER COATING TROUBLESHOOTING

TYPES OF METAL SUBSTRATE

PRETREATMENT (TO CLEAN THE METAL SUBSTRATE)

PHOSPHATING 7 TANK HOT PROCESS

COLD PROCESS (3 IN ONE)

7 TANK PROCESS WITH CHECK POINT

1. DEGREASING : CLEANING THE SHEET METAL SURFACE GREASE, OILS,SOILS,LUBRICANTS, OXIDE FILMS.

• CHEMICAL : ALKALINE DEGREASER
• TEMPERATURE : 60°C9±10°C
• POINTAGE : AS PER CHEMICAL SUPPLIER
• DURATION : 10-15 MINUTES

2. WATER RESIGNING: CLEANING THE SHEET METAL SURFACE GREASE, OILS, SOILS, LUBRICANTS, OXIDE FILMS.

• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5 MINUTES

3. DE-RUSTING: CLEANING THE SHEET METAL SURFACE OF RUST.

• CHEMICAL : RUST REMOVER
• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• POINTAGE : AS PER CHEMICAL SUPPLIER
• DURATION : 10 MINUTES

4. DM WATER RESIGNING: CLEANING THE SHEET METAL SURFACE OF RUST.

• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5 MINUTES
• PH VALUE : 5 TO 7

5. SURFACE ACTIVATION : SURFACE ACTIVATION FOR PHOSPHATING LAYER

• CHEMICAL : ACTIVATOR (AS PER CHEMICAL SUPPLIER )
• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5-10 MINUTES

6. PHOSPHATING

• CHEMICAL : ZINC OR IRON PHOSPHATE
• TEMPERATURE : 40°C+-10°C
• POINTAGE : AS PER CHEMICAL SUPPLIER
• DURATION : 5-10 MINUTES(ACCORDING JOB)

7. DM WATER RESIGNING

• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5 MINUTES
• PH VALUE : 5 TO 7

CHROMOTIZING PROCESS

NON-CHROMOTIZING PROCESS

ACID DEGREASING	WATER RINSING	ETCHING	WATER RINSING
CHROME-FREE	WATER RINSING	DRYING

CHROMATING PROCESS WITH CHECK POINTS

1. DEGREASING : CLEANING THE ALUMINUM SURFACE OF GREASE, OILS, SOILS AND LUBRICANTS FILMS.

• CHEMICAL : ACID DEGREASER
• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• POINTAGE : AS PER CHEMICAL SUPPLIER
• DURATION : 10-15 MINUTES

2. DM WATER RESIGNING

• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5-7 MINUTES
• PH VALUE : 5 TO 7

3. ETCHING : THE PURPOSE OF ETCHING PROCESS IS TO REMOVE THE THIN NATURAL OXIDE LAYER ON THE SURFACE BEFORE THE CHROMATING.

• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• POINTAGE : AS PER CHEMICAL SUPPLIER
• DURATION : 5 MINUTES

4. DM WATER RESIGNING

• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5 MINUTES
• PH VALUE : 5 TO 7

5. CHROMATING

• CHEMICAL : YELLOW & GREEN CHROME
• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5 MINUTES
• PH VALUE : 4 TO 5

6. DM WATER RESIGNING

• TEMPERATURE : AMBIENT ROOM TEMPERATURE
• DURATION : 5 MINUTES
• PH VALUE : 5 TO 7

SUBSTRATE DRYING

• AIR
• OVEN (TEMPERATURE 100 TO 120?C)

GUN BOOTH APPLICATION (MANUALLY & AUTOMATIC)

TYPES OF GUN:-

1. CORONA (MOSTLY THIS GUN USED)
2. TRIBO (FOR INTRICATES SHAPES)

TYPES OF OVENS (BATCH TYPE & CONVERISED)

1. GAS FIRED
2. DIESEL FIRED
3. ELECTRIC FIRED
4. BIO-FUEL FIRED

PROBLEMS & SOLUTIONS

CLASSIFICATION OF PROBLEMS

POWDER RELATED

• LUMPS FORMATION

APPLICATION RELATED

• FLUIDIZATION
• GUN SPITTING
• COVERING
• FILM THICKNESS
• RECYCLE POWDER

FINISH RELATED

• GLOSS
• FINISH
• COLOR CHANGE
• PIN HOLES
• ORANGE PEEL

MECHANICAL & CHEMICAL TEST

• IMPACT TEST
• BAND TEST
• CROSS HATCH TEST
• SST TEST
• QUV TEST

LUMPS FORMATION

POSSIBLE CAUSE	SUGGESTED SOLUTION
THE POWDER HAS BEEN STORE FOR TOO LONGER TIME OR TEMP TOO HIGH FOR STORAGE	KEEP POWDER COOL & DRY AREA. FILTER THE POWDER

GUN SPITTING

POSSIBLE CAUSE	SUGGESTED SOLUTION
POOR FLUIDIZATION IN POWDER HOPPER PUMP & BLOCKED HOSES NOT ADJUSTED PROPERLY PUMP & BLOCKED HOSES NOT ADJUSTED PROPERLY	INCREASE OR DECREASE THE FLUIDIZING AIR TO HOPPER CHECK BOTTOM OF HOPPER AND MEMBRANE FILTER INCREASE ATOMIZING/ DIFFUSER AIR CHECK ALL AIR TUBE CONNECTIONS FOR LEAK REDUCE THE AMOUNT OF RECLAIM POWDER

POOR PENETRATION (COVERING)

POSSIBLE CAUSE	SUGGESTED SOLUTION
INSUFFICIENT POWDER POOR EARTH INCORRECT SPRAY PATTERN VOLTAGE TOO FINE POWDER TOO FINE	INCREASE THE PUMP FLOW-RATE PRESSURE CLEAN THE HOOK AND RACKS, ALSO CHECK AND IMPROVED GROUNDING TRY DIFFERENT NOZZLES FOR DIFFERENT SURFACE REDUCE GUN VOLTAGE (Kv) REDUCE THE AMOUNT OF RECLAIM POWDER

COVERAGE

POSSIBLE CAUSE	SUGGESTED SOLUTION
POWDER DELIVERY RATE TO HIGH (EFFECT-THICKNESS) SHAPE OF SUBSTRATE INCORRECT SPRAY COATING METHOD RECYCLE POWDER EFFICIENCY POOR EARTH	POWDER DELIVERY RATE DECREASED (CONTROL-THICKNESS) DIFFERENT SHAPE CHANGE AREA CHECK GUN DISTANCE & COATING METHOD CHECK RECYCLE POWDER % CLEAN HOCKS , HANGER & IMPROVED GROUNDING

GUN PARAMETERS FOR POWDER

FINISH	SMOOTH	STRUCTURE	TEXTURE	METALLIC
CHARGING (Kv)	70-90	70-100	70-80	50-60
AIR (Kg/Cm3)	1.5-4.0	1.0-2.5	1.5-4.0	0.5-1.5
POWDER	As Per Required	As Per Required	As Per Required	As Per Required
CURRENT(????A)	20-40	20-40	20-40	20-30
FLUIDIZATION(Kg/Cm3)	As Per Required	As Per Required	As Per Required	As Per Required

FILM THICKNESS TOO LOW OR TOO HIGH

POSSIBLE CAUSE	SUGGESTED SOLUTION
POWDER DELIVERY TOO LOW INSUFFICIENT COATING TIME FARADAY CAGE EFFECT POOR EARTHING POWDER OUTPUT TOO HIGH	INCREASES COATING TIME OF COMPONENT ADJUST THE GUN VOLTAGE & OTHER PARAMETERS CLEAN HOOKS & RACKS TURN DOWN PUMP PRESSURE & MOVE GUN FARTHER AWAY FROM THE PARTS REDUCE GUN VOLTAGE REDUCE TIME OF COMPONENT COATING TIME

CRATERS & PIN HOLES

POSSIBLE CAUSE	SUGGESTED SOLUTION
OIL & OTHER CONTAMINATION ON PARTS CONTAMINATED COMPRESSED AIR CONTAMINATED POWDER MOISTURE IN AIR SILICON CONTAMINATION POOR SHEET QUALITY	CHECK CLEANING AND PRETREATMENT ENSURE COMPRESSED AIR IS FREE FROM OIL CLEAN THE EQUIPMENT AND RECHARGE WITH FRESH POWDER DRAIN OUT THE WATER FROM COMPRESSOR REMOVE LOCATED SOURCE POINT CHOOSE SPECIAL DEGASSING GRADE POWDER MICRO PINHOLE IN GPSP SHEET

GLOSS (TOO HIGH OR TOO LOW)

POSSIBLE CAUSE	SUGGESTED SOLUTION
CURE OVEN TEMP TOO LOW CURE OVEN TEMP TOO HIGH OVEN CYCLE TIME LOW & LONG CONTAMINATION WITH INCOMPATIBLE POWDER	INCREASE THE OVEN TEMP DECREASE THE OVEN TEMP ADJUST LINE SPEED & CURING TIME REMOVE ALL CONTAMINATED POWDER THOROUGHLY CLEAN ALL EQUIPMENT THEN USE FRESH POWDER

POOR ADHESION (CHIP-OFF)

POSSIBLE CAUSE	SUGGESTED SOLUTION
POWDER UNDER CURE POOR PRETREATMENT (OIL & DIRTY SURFACE) HIGH COATING PREHEAT AFTER PRE-TREATMENT PROCESS	INCREASE THE TEMP CHECK THE PRETREATMENT PROCESS ADJUST COATING AS PER PRODUCT STD CHECK CONDITION & SUGGESTED FOR PREHEAT

COLOR VARIATION

POSSIBLE CAUSE	SUGGESTED SOLUTION
FILM THICKNESS VARIATION DIFFERING SUBSTRATES & SUBSTRATE COLOR OVER CURING OF POWDER COATING	ASSURE CONSTANT FILM THICKNESS USE SUBSTRATE OF SAME TYPE FOR COMPARISONS OBSERVE CURING PARAMETERS OF POWDER MANUFACTURER

COLOR FADING

POSSIBLE CAUSE	SUGGESTED SOLUTION
CLEANING METHOD VERY POOR POOR PAINT FILM ADHESION SMALL PIN HOLE & DEGASSING ON FINISH SUN UV RAYS, MANY POLLUTANT SECTION ARE FASTER FADE SOME PLACE CHOOSE WRONG CHEMISTRY POWDER COLOR HAS A LIMITED LIFE EXPECTANCY	CHECK PRE-TREATMENT PROCESS CHECK TEMPERATURE CHEEK PINHOLE SOURCE DISCUSS CONDITIONS WITH MANUFACTURE CHOOSE OUTDOOR DURABILITY ARCHITECTURAL GRADE POWDER CONTACT MANUFACTURE

STRUCTURE PATTERN

POSSIBLE CAUSE	SUGGESTED SOLUTION
FLAT PATTERN SMALL PATTERN (PIN HOLE)	ADJUST THE AIR PRESSURE & LOWER THICKNESS INCREASE THICKNESS. LONG CURING TIME

DUSTING (FOREIGN PARTICLE IN FILM)

POSSIBLE CAUSE	SUGGESTED SOLUTION
SUBSTRATE SURFACE IS DIRTY BOOTH AREA IS NOT CLEAN POWDER IS TOO COARSE OR NOT SIEVED	CHECK THE PRETREATMENT PROCESS CLEAN THE SUBSTRATE BY AIR CLEANING CLEAN THE BOOTH AREA. SIEVE ALL RECLAIM POWDER

ORANGE PEEL (POOR FLOW)

POSSIBLE CAUSE	SUGGESTED SOLUTION
FILM THICKNESS IS TOO HIGH OR TOO LOW VOLTAGE TOO HIGH HEAT CYCLE OF THE TOO SLOW AIR PRESSURE IS TOO HIGH	CHECK SYSTEM PARAMETERS OPTIMIZE VOLTAGE DETERMINE THE HEAT UP CURVE AND INCREASE REDUCE THE AIR PRESSURE

CLOUD PROBLEM (CARBON LAYER) IN FINISH

POSSIBLE CAUSE	SUGGESTED SOLUTION
CORROSIVE URBAN ATMOSPHERE UNIFORM EXPOSURE TO AIR & ITS POLLUTANTS COATING DEFECTS OR COATING DAMAGE UNCURED SUBSTRATE CHLORIDE CONTAMINATION ON PHOSPHATE FILM DAMP MOISTURE FILMS OVER METAL SURFACE WET FILMS OF DEW & RAINWATER	USE CORROSION RESISTANT METAL OR ALLOY REDUCE ATMOSPHERIC POLLUTANTS DO REGULAR SURFACE CLEANING CHECK CURING TEMPERATURE REGULARLY AVOID COATING DEFECTS USE SUITABLE CORROSION INHIBITORS COATED SUBSTRATE PACKING AREA SHOULD BE DRY

CORROSION (RUST)

POSSIBLE CAUSE	SUGGESTED SOLUTION
CORROSIVE URBAN ATMOSPHERE UNIFORM EXPOSURE TO AIR & ITS POLLUTANTS COATING DEFECTS OR COATING DAMAGE UNCURED SUBSTRATE CHLORIDE CONTAMINATION ON PHOSPHATE FILM DAMP MOISTURE FILMS OVER METAL SURFACE WET FILMS OF DEW & RAIN WATER	USE CORROSION RESISTANT METAL OR ALLOY REDUCE ATMOSPHERIC POLLUTANTS DO REGULAR SURFACE CLEANING CHECK CURING TEMPERATURE REGULARLY AVOID COATING DEFECTS USE SUITABLE CORROSION INHIBITORS COATED SUBSTRATE PACKING AREA SHOULD BE DRY

USE OF RECYCLE POWDER

• MAINTAIN USE OF RECYCLE POWDER PERCENTAGE WITH MAXIMUM (70:30) RATIO. IF WE USE WITH HIGHER RATIO THAT CAUSE PROBLEM IN FINISH.

• USE RECYCLE POWDER ONLY AFTER SIEVING. IF WE USE WITHOUT SIEVING THAT CAUSE DUSTING.

• COLLECT THE RECYCLE POWDER SEPARATE BOX & COVER PROPERLY OTHERWISE FACE IN PINHOLE PROBLEM.

COLOR VARIATION (IN METALLIC)

POSSIBLE CAUSE	SUGGESTED SOLUTION
HIGH CHARGING HIGH AIR PRESSURE GUN DISTANCE TOO HIGH OR TOO LOW COLOR VARIATION IN RECYCLING	REDUCE THE CHARGING TO BELOW 60 KV OPTIMIZE THE AIR PRESSURE ADJUST THE GUN DISTANCE MAINTAIN 90/10 RATIO USE OF RECYCLE POWDER

TTR (TRAVELLING TEMPERATURE RECORDER)

• DATA LOGGER : TTR data logger is a portable measuring device that is capable of autonomously recording temperature over a defined period of time. The digital data can be retrieved, viewed and evaluated after it has been recorded.

• PROBE : The type K is the most common type of thermocouple.

• INSULATION BOX : It insulate heat to protect data logger.

TTR GRAPH RESULT NOT OK

TTR GRAPH RESULT OK

TTR RESULTS (CONVEYOR OVEN)