Film properties problems
Trouble |
Possible Causes |
Solution |
Color – Off shade
|
Stoving time too long |
Adjust line speed |
Oven temperature too high |
Decrease oven temperature |
|
Foul oven air |
Check gas supply, burners and venting. |
|
Bare Edges / Areas – Pinholing and gassing through coating surface |
Poor cleaning, metal preparation or dry-off |
Check pre-treatment equipment, dry-off oven and part drainage. |
Film Aspect – Texture pattern or metallic effect incorrect. |
Guns too close or distant from component |
Adjust distance. |
Powder delivery too high |
Adjust. |
|
Film thickness too high or low |
Adjust. |
|
Poor Mechanicals – Poor impact resistance, poor flexibility
|
Undercured |
Increase oven temperature. Increase dwell time in oven. |
Poor cleaning or pre-treatment |
Check pre-treatment equipment and chemicals. |
|
Film thickness too high |
Reduce film thickness by adjusting application equipment. |
|
Change in substrate thickness or type |
Check substrate with supplier. |
|
Adhesion – Poor adhesion
|
Poor cleaning or pre-treatment |
Check pre-treatment equipment and chemicals. |
Change in substrate thickness or type |
Check with substrate supplier. |
|
Undercured |
Increase oven time. Increase dwell time in oven. |
|
Chemical Resistance – Poor chemical resistance |
Undercured |
Increase oven temperature. Increase dwell time in oven. |
Surface Hardness – Poor pencil hardness, poor abrasion resistance
|
Undercured |
Increase oven temperature. Increase dwell time in oven. |
Overcured |
Reduce oven temperature. |
|
Poor Flow – Too much orange peel |
Film thickness too low / high |
Increase / decrease film thickness by adjusting application equipment. |
Oven temperature too low |
Set oven to correct temperature. |
|
Heat up rate too slow |
Modify oven baffling heat rate at front of oven. |
|
Gloss Too Low – Too low for high gloss powder |
Incompatible powder contamination |
Clean application equipment before changing powders. |
Micropinholing from gassing |
Check component for porosity. Check component for moisture. Check powder for moisture from reclaim or compressed air. Check film thickness, coating too thick. |
|
Gloss Too High – Too high for low gloss powder |
Undercured |
Check burners, isolate oven. Increase dwell time in oven. |
Contamination in Powder |
Reclaim in-line sieve torn |
Repair sieve or replace if necessary. |
Contamination from plant air circulated through spray booth |
Isolate and preferably enclose spray booth area. |
|
Film Thickness – Inconsistent film thickness |
Guns positioned incorrectly |
Check and reposition guns. |
Reciprocators not matched to line speed |
Adjust line speed. Adjust reciprocator stroke. |
|
Air speed in booth disturbing spray pattern |
Consult your equipment supplier. |
|
Defective spray equipment |
Consult your equipment supplier. |