Product design and process: plastic surface treatment process

The purpose of surface treatment is to meet the requirements of corrosion resistance, wear resistance, decoration or other special functions of products, also known as secondary processing.

1. Surface processing

advantage:

Make the surface smooth, bright and beautiful.

1.1。 Scrub

Frosted plastic generally refers to plastic film or sheet. When calendering, the roller itself has various patterns, which reflect the transparency of the material.

1.2. Polishing

Polishing is a processing method that uses mechanical, chemical or electrochemical actions to reduce the surface roughness of the workpiece to obtain a bright and flat surface.
The principle is the same as that of shoe cleaning. Dip the toothbrush evenly on the plastic with paraffin oil and kerosene, evaporate for a day, pull it left and right with silk such as socks, wipe it back and forth on the plastic surface, and then dry it.

2. Surface electroplating

advantage:

Decoration, beautification, anti-aging and corrosion resistance.

2.1。 Painting

Plastic spraying is to spray paint on the plastic surface to ensure the aesthetic and physical properties of the plastic.

Function: Coloring, obtaining different texture, preventing plastic from aging and corrosion resistance.

Plastic spraying process:

Annealing → Degreasing → Eliminating electrostatic precipitation → Spraying → Drying

Powder spraying: plastic powder is sprayed on the surface of the workpiece under the condition of electrostatic field, and then solidified into a protective layer under high temperature;

Spraying: the alloy powder is sprayed on the surface of the workpiece by heating to form a wear-resistant layer or fill the worn parts;

Spray paint: spray paint evenly on the surface of the workpiece with compressed air.

 

Paint spraying is oil spraying, including ordinary paint, UV paint, PU paint and rubber paint (hand paint).

Because UV paint is more environmentally friendly than PU paint, PU paint is gradually replaced by UV paint.

2.2. Printing

Plastic printing refers to the process of printing required patterns on the surface of plastic parts.

It can be divided into screen printing, curved surface printing (pad printing), hot stamping, penetration printing (transfer printing) and etching printing.

2.2.1。 screen printing

The printing plate is reticulated. When printing, the ink on the printing plate leaks from the through hole of the plate to the substrate under the extrusion of the ink scraper.

Usually the silk screen is made of nylon, polyester, silk or metal mesh.

Plastic screen printing applications:

1) ABS plastic

2) Appearance of plastic parts of electronic products

3) Plastic label

4) Soft and hard plastic parts

5) Dashboard

6) Color polyester label

Screen printing:

The traditional method of plate making is manual plate making, while photochemical plate making is widely used in modern times.

This method of plate making is based on the screen plate. The screen plate is stretched on the screen plate frame, and then the screen plate is coated with photosensitive adhesive to form a photosensitive plate film, and then the positive plate is made into a plate that is tightly attached to the plate film. After exposure and development, the part of the printing plate that does not need to be inked receives light to form a solidified plate film, and the mesh is sealed to prevent ink penetration during printing. The part of the mesh that needs to be inked on the printing plate is not closed. During the printing process, ink is transferred to form ink on the substrate.

2.2.2。 Pad printing

As a printing method for printing words or patterns on the surface of plastic molded products, curved surface printing is often used.

Curved surface printing refers to the use of a piece of elastic rubber to print the words and patterns to be printed on the surface of plastic molding products with curved or slightly concave convex surfaces.

The principle of curved surface printing is to first put the ink into the intaglio with words or patterns, then copy the words or patterns onto the rubber, and then transfer the words or patterns onto the surface of plastic molding products with rubber, Finally, the ink is cured by heat treatment or ultraviolet radiation.