Common Faults and Solutions in Powder Coating: This Guide Will Last You a Year

In the process of powder coating, many enterprises will encounter various faults, such as coating peeling, bubbles, sagging, color difference, etc., which not only affect product quality, but also reduce production efficiency and increase costs. I have been working in the powder coating industry for many years, and I have compiled the 6 most common faults and detailed solutions. I have collected this article so that you don't have to panic when encountering problems in the future.

Fault 1: Coating peeling and poor adhesion. There are three main reasons: firstly, incomplete pre-treatment of the workpiece, resulting in oil stains, rust, and dust on the surface; Secondly, the curing temperature or time is insufficient, resulting in insufficient curing of the coating; The third issue is the poor quality of powder coating, which does not match the material of the workpiece. Solution: Thoroughly clean the surface of the workpiece, remove impurities through grinding, acid washing, and other methods to ensure a dry and smooth surface; Strictly adjust the curing temperature and time according to the powder instructions to ensure that the coating is fully cured; Choose high-quality powder coating that matches the material of the workpiece.

Fault 2: There are bubbles and pinholes in the coating. Main reasons: There is moisture and oil on the surface of the workpiece, and bubbles are generated when the moisture evaporates during spraying; Powder coating becomes damp and clumps, resulting in pinholes after spraying; There are impurities in the curing oven that adhere to the surface of the coating. Solution: After pre-processing, the workpiece should be thoroughly dried to avoid surface moisture; When storing powder coatings, keep them dry. After being damp, they can be dried before use; Regularly clean the curing furnace to keep it clean.

Fault 3: Coating sagging and uneven thickness. Main reasons: The distance between the spray gun and the workpiece is too close, and the dwell time is too long; Excessive powder output and high electrostatic voltage; Uneven movement speed during spraying. Solution: Adjust the distance between the spray gun and the workpiece (15-25cm), move the spray gun at a constant speed to avoid stopping; Adjust the powder output and electrostatic voltage according to the workpiece requirements to avoid excessive powder output; Strengthen operator training and standardize operating procedures.

Fault 4: Obvious color difference in coating. Main reason: Different batches of powder coatings result in color differences; Inconsistent spraying parameters and varying coating thicknesses; Uneven curing temperature leads to color changes. Solution: Try to use the same batch of powder coating as much as possible, and conduct small batch trial spraying for different batches first; Unified spraying parameters to ensure uniform coating thickness; Check the temperature of the curing furnace to ensure uniform temperature inside the furnace.

Fault 5: The powder does not apply and the adsorption effect is poor. Main reasons: Low static voltage, insufficient powder charging; The workpiece is not grounded or poorly grounded; Poor flowability of powder coating and blockage of spray gun due to clumping. Solution: Increase the electrostatic voltage to ensure that the powder is fully charged; Check the grounding condition of the workpiece to ensure good grounding; Clean the spray gun and powder supply device, crush the agglomerated powder, and ensure the flowability of the powder.

Fault 6: There are impurities and particles on the surface of the coating. Main reason: There is dust in the spraying environment, which adheres to the surface of the workpiece; Impurities are present in powder coatings; There are debris inside the spray gun, blocking the powder outlet. Solution: Keep the spraying environment clean and clean it regularly; Filter the powder coating before use to remove impurities; Regularly clean the spray gun and keep the powder outlet unobstructed.