A new revolution in surface treatment: Sandblasting technology helps enhance quality and durability

What is sandblasting?

Sandblasting is a process that uses compressed air to spray particles (such as quartz sand, glass beads, steel beads, etc.) at high speed onto the surface of a workpiece for treatment. Its main function is to clean the metal surface, remove rust, oxides, oil stains and impurities, and at the same time, it can improve the adhesion, wear resistance and corrosion resistance of the parts by changing the surface roughness. The sandblasting process is widely used in surface treatment of different materials such as metals, plastics and glasses.

The principle of sandblasting process

The core principle of the sandblasting process is to use compressed air, high-speed water flow or other power sources to spray abrasive materials (such as quartz sand, corundum, steel balls, glass beads, etc.) at high speed onto the surface of machined parts. These high-speed moving abrasive materials are like countless tiny “bullets”, continuously impacting and cutting the surface of the parts, thereby causing a series of physical changes.

From a microscopic perspective, the impact of the abrasive materials can effectively remove various impurities on the surface of the parts, such as rust, oxide layer, oil stains, old coatings, and burrs and minor flaws generated during the machining process. During this process, the microscopic structure of the part’s surface changes, forming uniform tiny depressions, which realizes the surface roughening. This roughened surface not only increases the surface area but also introduces certain residual compressive stress on the surface of the part.

Surface roughening is of great significance for subsequent coating, bonding, and other processes. A larger surface area provides more attachment points for the coating, significantly enhancing the adhesion between the coating and the part’s surface, enabling the coating to adhere more firmly to the part’s surface, effectively preventing the coating from peeling off, thereby extending the service life of the coating and improving the protective performance of the part. The residual compressive stress introduced on the part’s surface helps to increase the fatigue strength of the part. During the operation of mechanical parts under alternating loads, the residual compressive stress can counteract some tensile stress, inhibit the initiation and expansion of fatigue cracks, and thereby significantly extend the fatigue life of the part and improve its reliability and stability under complex working conditions.

The function and effect of sandblasting

Sandblasting is not merely a cleaning process; it has demonstrated extremely high practical value in many fields. The specific functions are as follows:

Remove the oxide layer and dirt

Sandblasting can effectively remove the oxide layer, rust, grease and other dirt from the metal surface, restoring the surface of the part to its original state and providing a good base for subsequent processing steps (such as painting, electroplating, etc.).

Surface roughening treatment

Sandblasting can alter the roughness of the surface of parts, making it more uniform. This characteristic plays a significant role in certain fields where surface adhesion is required to be strong, especially in processes such as spraying and electroplating.

Improve surface hardness and wear resistance

After sandblasting, a certain compressive stress will be formed on the surface of the part, which helps to increase the hardness and wear resistance of the surface, reduce the wear of the part during use, and thereby extend the service life of the product.

Remove residual stress

For processed metal parts, sandblasting not only helps remove impurities from the surface, but also can eliminate some residual stresses, thereby reducing the risk of part deformation.

The advantages of sandblasting technology

Effectively enhance the fatigue strength of the parts

The residual compressive stress introduced on the surface of the part during the sandblasting process is a key factor in enhancing the fatigue strength of the part. In practical mechanical engineering applications, especially for those parts subjected to alternating loads, such as engine crankshafts, gears, springs, etc., fatigue failure is one of the common failure forms. The residual compressive stress can counteract part of the tensile stress in the working stress, delay the formation and expansion of fatigue cracks, and thereby significantly increase the fatigue life of the part. According to experimental data, after some key mechanical parts undergo sandblasting treatment, their fatigue life can be extended by 2 – 3 times or even more. This is of great significance for improving the reliability of mechanical equipment, reducing the frequency of failures, and lowering maintenance costs, and has made the sandblasting process widely applied in fields such as aerospace, automotive manufacturing, and mechanical engineering, where the reliability of parts is extremely demanding.

Widely applicable materials

The sandblasting process is applicable to the mechanical processing parts of various materials, including various metal materials (such as steel, aluminum alloy, copper alloy, stainless steel, etc.), non-metal materials (such as plastic, ceramic, glass, etc.) and composite materials. Different parts made of different materials can be treated with appropriate abrasives and process parameters according to their characteristics to achieve the expected surface treatment effect. For example, for harder metal materials, harder abrasives such as diamond sand and steel balls can be selected for sandblasting; while for relatively softer materials such as plastic and aluminum alloy, quartz sand and glass beads can be chosen to avoid excessive damage to the surface of the parts. The wide applicability of this process enables it to play an important role in mechanical processing in various industries, providing an effective solution for the surface treatment of various material parts.

Good shape adaptability

Whether it is a simple flat-shaped part or an irregular part with complex curved surfaces and internal cavities, the sandblasting process can achieve uniform surface treatment. By adjusting the spraying angle and movement trajectory of the spray gun, as well as using special tooling fixtures, it is possible to ensure that the abrasive can be evenly sprayed onto all parts of the part, including inaccessible corners and hidden areas. This advantage makes the sandblasting process particularly advantageous in processing mechanical parts with complex shapes, such as aircraft engine blades, automotive component molds, medical device components, etc. In the manufacturing process of aircraft engine blades, the sandblasting process not only can remove the oxide scale and processing marks on the blade surface, but also can form a uniform roughness on the blade surface, improving the blade’s fatigue resistance and aerodynamic performance, and ensuring the efficient and stable operation of the engine.

The implementation steps of the sandblasting process

The implementation of the sandblasting process usually involves the following key steps:

Cleaning and Preparation

Before sandblasting, the surface of the part should be ensured to be free of oil stains, dust and other adhering substances. Usually, solvent cleaning or mechanical cleaning is required to ensure that the surface is completely clean, to avoid affecting the sandblasting effect.

Select the sandblasting medium

The selection of sandblasting medium is of vital importance as it directly affects the treatment effect and the final quality of the parts. Common sandblasting media include quartz sand, glass beads, aluminum oxides, steel beads, etc. Different materials and particle sizes of media are suitable for different surface treatment requirements of parts. For instance, glass beads are suitable for fine surface treatment, while quartz sand is used to remove severe rust and oxides.

Adjust the sandblasting equipment and process parameters

The sandblasting equipment is mainly composed of a spray gun, a compressed air system and a sand storage tank, etc. The operator adjusts the appropriate air pressure, spray flow rate, spray angle and other process parameters according to the material, size of the part and the requirements of sandblasting, to ensure the expected effect.

Sandblasting operation

During the sandblasting process, the sandblasting machine uses compressed air to spray granular media at high speed onto the surface of the parts. The media collides with the surface, removing oxides, impurities and increasing the surface roughness. During the sandblasting process, it is necessary to control the distance between the sandblasting gun and the part surface as well as the sandblasting time to avoid excessive wear on the parts.

Post-processing

After sandblasting, the parts usually need to be cleaned and inspected. The residual sandblasting particles and debris should be removed, and necessary rust prevention treatments should be carried out to ensure that the surface of the parts is smooth and free from contamination.

The application fields of sandblasting technology

The field of mechanical manufacturing

In the field of general mechanical manufacturing, sandblasting is a commonly used surface treatment method, widely applied in the manufacturing process of various mechanical components. For castings, sandblasting can effectively remove sand particles, oxide scales, and other impurities from the surface, making the casting surface smooth and flat, which is conducive to subsequent machining and coating. At the same time, sandblasting can also improve the microstructure of the casting surface, increase its hardness and wear resistance, and extend the service life of the casting. For example, large castings such as machine bed frames, gearboxes, pump bodies, etc., usually require sandblasting treatment before processing to ensure the dimensional accuracy and surface quality of the parts.

During mechanical processing, the surface of parts often leaves cutting marks, burrs, and oil stains, which not only affect the appearance of the parts but also may reduce their performance. Sandblasting technology can easily remove these surface defects, making the part surface smoother and flatter, and improving the assembly accuracy and working performance of the part. For some mechanical parts that require surface strengthening, such as gears, shaft parts, etc., sandblasting treatment can form a residual compressive stress layer on the surface, improving the fatigue strength and wear resistance of the part, thereby enhancing the overall reliability and service life of the mechanical equipment. In addition, in the field of mechanical maintenance, sandblasting technology is also often used to repair the surface of worn or corroded parts. By removing the damaged layer on the surface and performing appropriate surface treatment, the original performance of the part can be restored, extending the service life of the part, and reducing maintenance costs.

The automotive manufacturing industry

Automobile manufacturing is a large-scale and highly precise industry, with strict requirements for the quality and appearance of components. The sandblasting process plays a crucial role in every stage of automobile manufacturing. During the manufacturing of automobile engines, key components such as cylinder blocks, cylinder heads, crankshafts, and connecting rods need to undergo sandblasting treatment to remove oxide scales, burrs, and oil stains generated during casting or machining, improving the cleanliness and roughness of the part surfaces, and enhancing the effectiveness of subsequent coatings or heat treatments. For example, after the engine cylinder block undergoes sandblasting treatment, the surface quality of its inner and outer walls is significantly improved, which is beneficial for enhancing the sealing between the piston and the cylinder wall, reducing the fuel consumption and emissions of the engine, and prolonging its service life.

The manufacturing of automobile bodies also cannot do without the sandblasting process. After the body panels are formed through stamping, the surfaces will still have oil stains and stamping marks. Through sandblasting, these impurities can be completely removed, making the body surface smoother and more flat, providing a good base for the painting process. The surface of the body panels after sandblasting has stronger coating adhesion, which can effectively prevent rust and corrosion of the body and improve the appearance quality and durability of the car. In addition, components such as car wheels, bumpers, and interior parts often use sandblasting for surface treatment to achieve different appearance effects and functional requirements. For example, after the aluminum alloy wheels undergo sandblasting treatment, they can present a fine matte texture, enhancing the beauty and grade of the wheels; while the sandblasting treatment of interior parts can improve their surface feel and visual effect, enhancing the overall comfort and luxury of the car interior.

The field of architectural decoration

In the architectural decoration industry, sandblasting technology is widely used for surface treatment of building materials such as stone, glass, and metal, to create unique decorative effects and meet specific functional requirements. For stone materials, such as marble and granite, sandblasting can change the texture and glossiness of the stone surface, creating different decorative styles. By controlling the duration, pressure, and abrasive particle size of the sandblasting, a variety of effects can be achieved, ranging from smooth surfaces to rough textures, from high gloss to matte finishes. For example, in the exterior wall decoration of some high-end buildings, sandblasted marble panels can present an ancient and natural texture, complementing the overall style of the building; while in interior floor and wall decorations, sandblasted stone can increase the friction of the floor, enhance safety when walking, and add a unique artistic atmosphere to the indoor space.

In the glass decoration field, sandblasting technology is often used to produce frosted glass, art glass, and other products. By sandblasting the surface of glass, it can create uniform tiny depressions, achieving a transparent yet non-translucent effect, and increasing the artistic beauty of the glass. Sandblasted glass is widely used in architectural decoration components such as doors, partitions, screens, etc., meeting the lighting requirements of the space, protecting privacy, and adding a soft and warm atmosphere to the indoor environment. In addition, in the surface treatment of building metal decoration materials, such as aluminum alloy doors, stainless steel railings, and ironwork products, sandblasting technology can remove surface oxide scales and oil stains, improve the smoothness and roughness of the surface, enhance the adhesion of subsequent coatings or platings, and make the metal surface present uniform and consistent color and texture, improving the overall quality and grade of architectural decoration.

Conclusion

The sandblasting process for mechanical processing parts not only effectively removes surface impurities, but also enhances the surface roughness and improves the wear resistance, thereby significantly improving the overall performance of the parts. In various industries such as aerospace, automotive, mold manufacturing, and mechanical part processing, sandblasting plays a crucial role. By selecting the appropriate sandblasting medium and process parameters, the best surface treatment effect can be achieved, providing a strong guarantee for the quality of the products.

Whether it is improving the surface quality of parts, enhancing the adhesion of coatings, or increasing corrosion resistance and wear resistance, the sandblasting process is an effective technique. For manufacturing enterprises, mastering the sandblasting process and using it appropriately will help enhance the competitiveness of products and extend the service life of parts.

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