Sandblasting Surface Treatment Process in Machining

Sandblasting uses compressed air to form a high-speed jet stream that propels abrasive materials onto the surface of a workpiece, causing physical changes to the surface to meet quality requirements.

Sandblasting uses compressed air to form a high-speed jet stream that propels abrasive materials onto the surface of a workpiece, causing physical changes to the surface to meet quality requirements.

I. Features of Sandblasting

1. Thorough and Efficient: Sandblasting is the most thorough, versatile, fast, and efficient cleaning method.
2. Adjustable Roughness: Sandblasting allows for flexible roughness adjustments, which cannot be achieved with other methods. For instance, manual grinding can create a rough surface but is slow, while chemical cleaning often leaves surfaces too smooth for coating adhesion.

II. Applications of Sandblasting

Sandblasting can clean, strengthen, and beautify surfaces of both metal and non-metal workpieces.

1. Pre-treatment: Prepares surfaces for processes such as electroplating, painting, PU coating, rubber or plastic coating, metal spray welding, and titanium plating by enhancing adhesion.
2. Surface Beautification: Decorative processing for metal products, creating matte or satin finishes for electroplated items, and frosting surfaces of non-metal products like acrylic, polyester, and crystal glass.
3. Surface Cleaning: Removes oxidation layers, heat treatment scale, pores, rust, and contaminants on metal and non-metal surfaces. It can also clean ceramic discoloration, regenerate painted surfaces, and remove mold residues.
4. Deburring: Removes burrs from plastics, phenolic products, zinc-aluminum castings, and refines surfaces of electronic or other components.
5. Electronics: Removes surface impurities on silicon chips after diffusion, etches silicon chips into smaller wafers, removes excess glue from encapsulated parts, cleans ceramic heating materials, and erases surface markings.
6. Surface Etching: Decorative etching for precious metals, gemstones, glass, stone seals, ceramics, and wood surfaces.
7. Stress Relief: Cleans aerospace components, relieves stress, and repairs and derusts defense equipment, while also removing paint and creating a matte finish.
8. Mold Processing: Creates textured or matte finishes on mold surfaces, enhances PU adhesion, and cleans or textures molds for shoes, conductive rubber, tires, and electronics.

III. Differences Between Shot Peening and Sandblasting

Both shot peening and sandblasting use high-pressure air or compressed air to impact the workpiece surface for cleaning. However, the choice of media leads to different results:

1. Sandblasting:

   • Removes surface contaminants and slightly damages the surface, significantly increasing surface area, thereby improving coating or plating adhesion.
   • Produces a matte finish as the roughened surface diffuses light, lacking metallic luster.

2. Shot Peening:

   • Cleans the surface without significant damage while slightly increasing surface area.
   • Enhances surface strength due to the excess energy from the process, which strengthens the substrate.
   • Produces a semi-matte finish, as the spherical surface partially diffuses light.

Both techniques play vital roles in machining and are selected based on specific requirements.