In the mass production process of spray painting assembly line, various paint quality defects are prone to occur due to factors such as equipment parameters, workshop environment, paint ratio, and process flow. Most factories repeatedly rework but cannot cure the problem, and the core is the failure to identify the root cause of the problem. This article summarizes six high-frequency faults in the paint spraying line and provides precise solutions.

1、 Paint surface sagging. Manifested as localized accumulation and flow of paint surface, forming water like marks, often appearing on the surface of vertical workpieces. The main reasons are excessive paint output, close spraying distance, thin paint ratio, and low drying temperature. Solution: Adjust the paint output and atomization pressure of the spray gun, control the paint dilution ratio, maintain the standard spraying distance, gradually heat up and dry, and avoid thick spray accumulation.

2、 Paint particles and dust spots. The paint surface is uneven and covered with small particles, which seriously affects the appearance. The causes are inadequate purification of the spray booth, excessive dust in the workshop, incomplete dust removal of workpieces, and unclean paint filtration. Solution: Regularly clean the spray booth filter and purification system, thoroughly remove dust before spraying, finely filter before painting, and maintain a dust-free and ventilated environment in the workshop.

3、 Pinhole and bubble defects. Small voids and bubble rupture marks appear on the paint surface, affecting corrosion resistance and aesthetics. Mainly caused by water and oil content in the workpiece, water and oil in compressed air, moisture in the paint, and rapid heating during drying. It is necessary to strengthen the drying of workpieces, install oil-water separators, standardize paint storage, and adopt gradient heating baking.

4、 Peeling and peeling of paint during spray painting. The paint surface peels off with a light touch, and the adhesion is seriously not up to standard. The root causes are unclean pre-treatment, residual oil stains, excessively smooth workpiece surfaces, and insufficient curing and baking. We need to improve the degreasing and dust removal process, perform grinding and roughening treatment on smooth substrates, and calibrate the drying temperature and cycle.

5、 The paint surface is rough with orange peel. Uneven paint surface, rough texture, and lack of luster. The causes are insufficient air pressure, high paint viscosity, rapid movement of the spray gun, and high curing temperature. By optimizing the paint ratio, adjusting the spraying parameters, and stabilizing the furnace temperature, it can be effectively improved.

6、 Batch color difference. The same batch of products have varying shades of color and significant differences in gloss. Mainly caused by unstable assembly line speed, furnace temperature fluctuations, different paint batches, and uneven mixing. Unified production parameters, thorough mixing of paint, and uniform use of materials in the same batch can eliminate the problem of color difference in batches.