About Painted Sheet Metal

Hanging jig marks

  • Hanging jig marks from plating and painting may remain (See figure below).
  • For information on modelling hanging holes, please refer to ‘Hanging Holes for Plating/Painting’.

Example of hanging jig marks on plated products

Example of hanging jig marks on painted products

Coating thickness and coating quality

The coating thickness of plated products is generally as shown in the table below.

Surface TreatmentFilm thickness *1
Electroless Nickel Plating5-10μm
Black Oxide1μm-
Trivalent Chromate (clear)5-15μm
Trivalent Chromate (Black)8-13μm
Anodized (clear)5-15μm
Anodized (Black)10-15μm
Anodize (matt black)
Trivalent Chromate Passivation (SurTec 650)0.1-1.0μm

Hanging jig marks may be left when painting (see diagram on right).

The base coat of painted products is iron phosphate coating.

The main quality standards are shown in the table below.

The values are approximate values.

Powder Coating Painting
Film thickness *1 80±30μm
  • 80±30μm
  • (With primer coating)
  • 30±15μm
  • (Without primer coating)
Baking temperature 180℃ 140℃
Baking time 20 to 30 min.
Salt spray test *2 120 hours 72 hours
1: Not a guaranteed value as the coating thickness may vary depending on the shape. 2: Based on JIS Z2371 salt spray test method. (Powder coating: 60±5μm after baking at 180°C for 20 minutes, Painting: 25±5μm after baking at 100°C for 20 minutes)

We conduct confirmation using a film thickness gauge, peeling off with tape, and board test with a test piece.
The appearance is visually checked for color, dust, spots, dimples, etc., referring to the “Miscellaneous Materials Measurement Chart,” and the tapped holes are checked for functionality by passing bolts through them.

For cleaning, wipe with water or wipe with water after wiping with diluted neutral detergent using a soft cloth or sponge, and then wipe dry with dry cloth.

Please refrain from using petroleum solvents such as thinner, benzene, etc. and alcohol.

Appearance: black oxide coating

  • The parts are shipped with a rust preventive applied to the surface.
  • However, depending on the amount of residual oil, colour unevenness may occur easily, and it may be particularly noticeable on larger products.
  • Even if colour unevenness occurs, there is no issue with the coating performance.
  • Please note that once the oil is removed, rust may develop more quickly.

If colour unevenness is not acceptable, please also consider using trivalent chromate (black) or coating (black).

Example where colour unevenness is noticeable due to low surface oil content.

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