Identification |
Possible cause |
Remedial action |
---|---|---|
From insufficient film thickness to finely textured surface | Insufficient deposition | Increase high voltage, check spray nozzles |
Output of powder too low | Increase powder flow | |
Blowing-off effect | Reduce amount of air | |
Flow of powder too high, together with low application voltage | Reduce powder output, increase voltage | |
Insufficient charging during tribo application | Use appropriate charging method (corona charging) |
Checklist for a problem-free powder coating process
Specific characteristics metallic powders
Insufficient levelling, rough surface
Colour variation
Identification |
Possible cause |
Remedial action |
---|---|---|
"greying", missing metallic effect | Wrong or different charging procedure, hence a different alignment of metal effect pigments | Corona charging recommended, standard application procedures need to be used for each powder |
Objects do not match in terms of colour or effect | Powder being used is not correctly bonded and cannot be reclaimed; results in separation of powder base and metal effect pigments | Use powder that can be reclaimed (bonded), ensure that the ratio of virgin powder to reclaim meets the powder manufacturers recommendations; motto "Stop messing about with half measures, and do the thing properly." |
Use powder "spray to waste" (costs, disposal) | ||
Batch change during a job | Use same batch of powder during a single job | |
Powder separating in powder hopper | Use fluidised bed hopper to avoid partial separation | |
Objects do not match in terms of colour or effect | Colour differences between automatic and manual coating process | If possible, do not use manual coating after automatic application but do any manual coating prior to automatic application |
Different substrates | Produce colour standard and colour tolerance standards for different substrates | |
"Differences" with the customer regarding the colour | Agree upon colour standard and agree tolerances confirmed by standard panels |
Clouding
Identification |
Possible cause |
Remedial action |
---|---|---|
Appearance of irregular light dark effects on substrate | Wrong space between sprayguns, different charging, improper sine curve, insufficient earthing | Optimise coating plant parameters |
Obviously different film thicknesses | Minimise variations in film thickness | |
Automatic coating process with subsequent manual application | Use manual pre-coating where manual reinforcement is required |