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Surface treatment of sheet metal: sandblasting
2025-08-28
What is sandblasting?
Sandblasting is a surface treatment method that uses high-speed abrasive jets to impact and rub the workpiece surface to clean, remove rust, increase surface roughness, and improve coating adhesion. This process is widely used for surface treatment of metals, glass, ceramics, plastics, and other materials.
The basic principles of sandblasting
Sandblasting uses compressed air or high-pressure water to accelerate abrasive material and spray it through a nozzle onto the workpiece surface. The high-speed impact creates friction and collision with the workpiece surface, cleaning, polishing, and roughening the surface. Common abrasives include quartz sand, corundum, glass beads and steel shot.
Types of sandblasting processes
According to different working principles and equipment used, sandblasting processes can be divided into the following types:
1. Dry blasting: Using compressed air as a power source, dry abrasive is sprayed onto the workpiece surface. This is the most common blasting method and is suitable for surface treatment of most metal and non-metal materials.
2. Wet blasting: A certain proportion of water is added to the abrasive, and the mixture is blasted. Wet blasting can effectively reduce dust pollution and improve the cleanliness of the workpiece surface, making it suitable for applications with high environmental requirements.
3. Vacuum blasting: This method utilizes vacuum equipment to recycle abrasive and dust, creating a closed loop system. This method is suitable for applications requiring stringent dust control, such as surface treatment of high-precision electronic components and medical devices.
4. Liquid sandblasting: Abrasives are sprayed onto the sheet metal surface through high-pressure water flow, suitable for cleaning and removing pollutants such as oil, rust, etc.
Specifications and differences of sandblasting processes
The specifications of the sandblasting process are mainly determined by the following factors:
1. Abrasive type: Different abrasives have different hardness, particle size and shape, suitable for different sheet metal surface treatment needs.
2. Abrasive grit size: The grit size of the abrasive determines the fineness of the surface treatment. The smaller the grit size, the finer the surface treatment; the larger the grit size, the rougher the surface treatment.
3. Jet pressure: The jet pressure affects the impact force of the abrasive, thus affecting the surface treatment effect. The higher the pressure, the faster the treatment speed, but it may also cause surface damage.
4. Jet angle: The jet angle determines the contact mode between the abrasive and the workpiece surface. Different angles will produce different surface effects.
5. Jet distance: Jet distance affects the distribution and impact force of the abrasive. The closer the distance, the greater the impact force.
Common abrasives and their application scenarios
1. Quartz sand: Quartz sand is one of the most commonly used abrasives with moderate hardness. It is suitable for removing oxide layers, rust spots and old paint layers on metal surfaces.
2. Diamond: Diamond has high hardness and is suitable for processing workpieces that require higher surface hardness, such as surface treatment of stainless steel and alloy steel.
3. Glass beads: Glass beads are spherical and have less impact force. They are suitable for processing workpieces with high requirements for surface finish, such as surface polishing of aluminum products and stainless steel.
4. Steel shot: Steel shot has high hardness and strong impact force, and is suitable for processing workpieces with high requirements on surface roughness, such as surface cleaning and strengthening of cast iron and steel.
Application areas of sandblasting technology
1. Metal surface treatment: Sandblasting is widely used in surface cleaning, rust removal, oxide scale removal and old paint removal of metal parts, providing a good surface foundation for subsequent coating and electroplating processes.
2. Mechanical manufacturing: In the mechanical manufacturing process, sandblasting is used to deburr parts, remove welding slag and roughen the surface, thereby improving the surface quality and performance of parts.
3. Aerospace: Sand blasting is used in the aerospace field to clean and treat the surface of parts to improve the fatigue strength and corrosion resistance of parts.
4. Automobile manufacturing: Sand blasting is widely used in the surface treatment of automobile parts, such as cleaning, rust removal and surface treatment of car bodies, wheels and engine parts.
5. Electronics and electrical appliances: Surface cleaning and treatment of electronic components and electrical parts, using sandblasting technology to improve surface quality and service life.
6. Architectural decoration: Sandblasting is used for surface treatment of glass, stone and wood to create unique surface effects and decorative effects.
Advantages and Challenges of Sandblasting
Advantages:
Efficient cleaning: Sandblasting can quickly remove rust, oxide layers and pollutants on the surface with high efficiency.
Improve adhesion: By roughening the surface, the adhesion of coating and electroplating layers is improved, thus extending the service life.
Versatility: Suitable for a variety of materials and surface treatment requirements, with a wide range of applications.
Challenge:
Dust pollution: A large amount of dust will be generated during the dry sandblasting process, which will affect the operators and the environment and corresponding protective measures need to be taken.
Surface damage: High-pressure jetting may cause damage to the workpiece surface. It is necessary to control the jetting parameters and select appropriate abrasives.
Equipment cost: Sandblasting equipment and abrasives are expensive, and the initial investment is large.
Sandblasting, as an important surface treatment method, is widely used across various industrial sectors. By selecting the appropriate abrasive, particle size, spray pressure, and angle, various surface treatment effects can be achieved. While sandblasting presents some challenges, its efficiency and versatility make it valuable in metalworking, machinery manufacturing, aerospace, automotive manufacturing, electronics, and architectural decoration.