5 plating

5.1 The surface of the workpiece is coated with a metal film to prevent corrosion, wear, lubrication, electrical conductivity, etc.

Such as: white zinc plating, color zinc, copper plating, etc.

5.3 Coating specifications for different materials

Bottom Metal Parts Parts Category Plating Category Plating Thickness (μm)

carbon steel

General structure

Parts Copper / Chromium / Nickel 12~15

Zinc 12~15

Cadmium 9~12

Fastening

Parts Zinc 9~12

Cadmium 12~15

Elastic parts zinc 12~15

Cadmium 9~12

Copper and

copper

Alloy

Parts Chrome/Nickel 9~11

Nickel or high tin bronze 9~12

Fastening parts Nickel or high tin bronze 6~9

Elastic parts Nickel 6~9

Note: The reasons for the peeling of the coating are: 1. The workpiece is not cleaned before plating. 2. The plating solution is poor and has impurities.

6 spraying

6.1 baking varnish

6.1 Surface treatment before baking: derusting, degreasing, phosphating.

General requirements and processing of paint on the workpiece:

(1) The paint needs to be flat on the surface of the workpiece, and the unevenness affects the appearance.

(2) If there is a through hole on the required paint surface, the hole must be unilaterally added with 0.1mm to avoid the hole being reduced due to baking paint.

(3) If there are through-hole studs on the painted surface, nuts and direct tapping threads shall be marked and specially reminded to avoid the adhesion of the paint to the threads and cause defects.

(4) The workpiece after baking is generally not subject to external impact, such as bending, stamping, etc. to avoid peeling off the paint layer.

(5) The surface of the painted workpiece

(6) Inspection method of baking varnish: use a single-sided blade to cut the lacquer film, four vertical and horizontal lines, with a line spacing of 1 mm to form a small square with a side length of 1 mm, and then compact it with adhesive tape, then suddenly force upward obliquely upward Pull open and observe the paint film.

6.2 Introduction to Huawei Surface Processing Code

7 silk screen

7.1 Silk screen process requirements and precautions:

(1) The silk screen process is usually the last processing step (the next step is assembly), and before the silk screen, there are surface treatments, such as: plating, baking, oxidation and other surface treatment.

(2) Although the surface of the screen printing workpiece may have a convex portion, the required silk screen area cannot be uneven, and there is no sharp edge near the silk screen area to avoid the screen rupture when the silk screen is printed.

(3) The silk screen of the workpiece must be positioned. When the process is arranged, it must be considered whether it can be positioned when the silk screen is printed. If necessary, the positioning fixture can be added.

(4) The workpiece after silk screen printing must be baked in the oven, so there should be no objects damaged by high temperature on the workpiece.

polishing

Advantage: If the ordinary stainless steel is polished, it can get a mirror-like bright surface.

The slag on the workpiece after spot welding can be removed by a polishing machine. For example, it is easy to grind into a flat surface with a grinder.