Quality standards and inspection method of powder coating products



The powder coating process is widely used in the manufacturing industry. The surface of the product after the powder coating process will become smoother, and a variety of colors can be sprayed to improve the overall visual effect of the product. In addition, the adhesion of spray plastic is stronger than ordinary paint and has a strong corrosion resistance.

The following are the quality requirements and inspection method of powder coating products:

1. Purpose
Ensure product inspection and standardization to achieve uniform and effective quality control of products.

2. Scope of use
It is suitable for the inspection of each plastic-sprayed parts before leaving the factory.

3. Reference standard
The clauses contained in the following standards, which are quoted in this standard to constitute the clauses of the standard, are valid when the standard is published.
GB1182-80~GB1184-80 shape and position tolerance


4. Inspection method
The new products are jointly inspected and confirmed by the technical department and the quality inspection department. Check that the structure of the spray-painted product meets the requirements of the drawings, and that the external screen printing of the spray-painted products meets the requirements of the drawings, including the location, color, size, and clarity of the screen printing.

5. Inspection content

5.1 Appearance

5.1.1 There should be no shrinkage holes, pinholes, impurity points, exposed bottom, obvious uneven thickness, tearing, poor pretreatment, rust, stains, pits, etc. inside the product surface. Note that there should be no obvious phenomena such as plastic powder hanging flow, accumulation, and spray leakage inside the product.

5.1.3 Spraying color: The spraying color should be consistent with the selected sample or color plate, and the technical requirements. The color of the product surface after spraying is uniform, and there is no obvious color difference by visual inspection.

5.2 Plastic product structure

5.2.1 Basic requirements: The dimensions of the powder coating products should meet the requirements of the drawings.

5.2.2 Inspection method: After the powder coating product is inspected, the key dimensions are measured to verify that the product structure is correct, the installation holes are not offset, the screw installation can be tightened in place, the cabinet door is tightly sealed, and the side panel is easy to install and remove; The riveting sleeve in the production is not allowed to loosen or even fall off

5.3 Thickness of spraying layer: 120-160μm, uniform thickness and strong adhesion.

5.4 Product cleaning: The surface parts inside and outside the product are visible, clean, without any stains such as oil stains and stains that affect the appearance, and no white traces are allowed.

5.5 External silk screen inspection requirements for powder coating products
Check that the screen printing content and color of the plastic-sprayed products meet the requirements of the drawing. The screen printing is clear, and no defects such as misprinting, missing printing, color mismatch, unrecognizable or defective large screen printing broken lines are allowed.

5.6 Inspection requirements for appearance defects of plastic-sprayed products

5.6.1 Rust: No rust phenomenon is allowed on the surface of the plastic-sprayed product. The thickness of the plastic-sprayed surface of the plastic-sprayed product should be uniform, and there should be no spray-off of the powder coating bottom.

5.6.2 Damage and deformation: the surface of the plastic-sprayed product is not allowed to be scratched or deformed, and the surface should be flat without corners and buckling.

5.6.3 Scratches: Piece scraps caused by friction are not allowed.

5.6.4 Particles: There should be no small pieces of Kelly, screen printing ink dots, bumps, protruding marks or flow marks on the surface of the sprayed product. Disperse and a small amount of particles are allowed.

5.6.5 Dimples: There should be no pits on the surface of the plastic-sprayed product, allowing dispersion and slight presence.

5.6.6 Scratch: The sprayed product must not have more than 0.2×10mm scratches, and the scratched part can be too deep to expose the bottom plate; there can be pieces of scratches on the surface of the sprayed product, allowing dispersion and a small amount of existence.

5.7 Gap: As long as the plastic-sprayed products are waterproof, no gaps are required (IP54 rating for outdoor and IP45 rating indoors).

5.8 Processing technology requirements

A. Strictly execute each process according to the production process, paying attention to the pickling and phosphating processes.

B. All nuts must be filled or sealed before spraying

5.9 Adhesion test:

Use a blade with a sharp edge, along with a guide that can ensure a straight cut. The edge is drawn at a constant speed of 35-45 degrees relative to the coating surface. The nearest distance between the scribe line and the edge of the product should not be less than 5mm. The cut must be cut to the substrate. On the coating film, cut out a grid pattern of 6 to 11 cuts in each direction. The cuts are separated by 1mm intervals and the length is about 20mm. After cleaning the grid area with a soft brush or soft paper, cover the grid area with 3M tape, rub the tape with your hands to ensure that it is fully adhered, and hold one end of the tape as close to 180 as possible from its original position in the direction of (do not violently), peel off the tape. If there is peeling of the coating or the coating falls off when the product is scratched with a blade, it is judged as unqualified.


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