How to enhance the texture and performance of aluminium profiles?

The brushed finish of an aluminium surface.

Among the many surface treatment processes, brushing has become one of the most widely used techniques due to its unique textured effect, excellent performance, and relatively low cost.Brushed aluminium surface treatment refers to a process in which mechanical friction, using tools such as abrasive belts and nylon wheels, is applied to the aluminium surface in a directional or non-directional manner. This removes surface material and creates a uniform, fine linear texture, achieving a specific surface effect.

The key characteristics of brushed aluminium surface treatment are as follows:

• High Aesthetic Appeal: The brushed aluminium surface exhibits a delicate metallic sheen and a unique textured effect, significantly enhancing the product’s quality and visual appeal.
• High Durability: Brushing removes minor surface imperfections from the aluminium and forms a dense surface layer, thereby enhancing its wear resistance, corrosion resistance, and scratch resistance.
• Easy to Clean: The brushed surface is resistant to fingerprints and stains, and even if they do appear, they can be easily wiped away, making daily maintenance more convenient.
• Well-Established Process: The brushed aluminium surface treatment is a mature technique with simple equipment, easy operation, and relatively low cost, making it well-suited for large-scale production.

The Principles of Common Brushed Aluminium Surface Treatments.

Mechanical Cutting Principle

• Using abrasive belts, grinding wheels, or wire brushes to apply unidirectional or multidirectional friction evenly removes the top layer of aluminium, creating a fine, linear texture.
• The effect of mechanical friction is equivalent to a slight cutting of the aluminium, but it does not affect its internal structure.
• Depending on the type of brushing tool used, different surface effects can be created, such as straight lines, cross patterns, wavy textures, or spiral patterns.

Metal Surface Deformation and Redistribution

• During the friction process, the metal material on the aluminium surface undergoes plastic deformation, and the material in localised areas is redistributed along the direction of friction, forming a regular brushed texture.
• Proper control of pressure and speed can ensure the uniformity of the brushing process, preventing the surface from developing dents or irregular scratches.

Abrasive grinding action

• By using sandpaper, abrasive belts, or polishing compounds of varying grits, the surface is gradually smoothed through a process of coarse grinding, medium grinding, and fine grinding, allowing for adjustment of the brushed texture’s coarseness.
• Coarser abrasive materials create deeper brushed textures, while finer particles produce a more delicate, silk-like finish.

Oxide layer treatment and subsequent protection

• During the brushing process, the aluminium surface removes part of the natural oxide layer, so anodising or coating treatment is required to prevent subsequent oxidation and corrosion.
• Anodising can also expand the colour options, making the brushed aluminium more decorative.

Factors Affecting the Brushed Effect

1. Type of tool (abrasive belt, wire brush, grinding wheel, etc.)
2. Abrasive particle size (coarse abrasives create deeper brushed textures, while fine abrasives produce shallower brushed textures)
3. Friction pressure and speed (affecting the depth and uniformity of the texture)
4. Brushing direction (determines the final visual effect, such as straight lines, cross patterns, etc.)
5. Aluminium surface treatment (whether the pre-treatment is uniform and free of impurities)

Different brushing effects are suitable for various scenarios. By adjusting equipment, process parameters, and abrasive materials, a wide range of aluminium surface brushing effects can be achieved.

Aluminium Surface Brushing Methods

Mechanical Brushing

Mechanical brushing is the most traditional and commonly used aluminium surface treatment method. It uses abrasive belts, grinding wheels, or brushing tools to create mechanical friction on the aluminium surface, removing the top layer of material and forming a regular brushed texture. This method is simple to operate, cost-effective, and allows for adjustments to the brushing direction and depth according to specific requirements.

However, as the process generates a significant amount of dust, dust extraction equipment is required to minimise environmental pollution and health risks for workers. Mechanical brushing is mainly used in applications such as electronic product casings, household appliance panels, and architectural decorative panels.

Wet Brushing

Wet brushing is similar to mechanical brushing but involves the use of lubricants, such as water or oil, during the process to reduce friction heat, minimise dust, and improve surface smoothness. This method creates a more uniform brushed texture while preventing material deformation or damage caused by overheating.

As wet brushing reduces scratches and enhances the smoothness of the aluminium surface, it is commonly used for high-end decorative panels, precision instrument casings, and metal products with stringent quality requirements.

Abrasive Belt Brushing

Abrasive belt brushing uses a high-speed rotating belt sander to create a brushed finish on the aluminium surface. This method is suitable for large-area brushing, offering high efficiency, and allows control over the texture’s coarseness by changing the grit size of the abrasive belt.

Abrasive belt brushing can create various effects, such as straight lines and cross patterns, making it widely used in the architectural decoration industry for large aluminium alloy sheets, doors and windows, curtain walls, and other applications.

Stainless Steel Brushed Finish

Stainless steel brushing uses metal brushing wheels (such as wire brushes or nylon brushes) to create friction on the aluminium surface, forming deeper brushed textures. This method produces coarser brushing patterns, giving the aluminium a unique tactile quality while also enhancing its surface hardness and wear resistance.

As this treatment method provides a stronger industrial aesthetic, it is primarily used for mechanical components, industrial equipment casings, and aluminium products with high durability requirements.

Polishing Compound Brushing

Polishing compound brushing is a refined brushing method, typically using polishing compounds in combination with cloth or grinding wheels to smooth the surface and achieve a finer, more polished brushed effect.

This method is suitable for products with high surface requirements, such as high-end household appliances, watch casings, and aluminium alloy accessories. Polishing compound brushing can create a near-mirror effect while avoiding the roughness typically produced by mechanical brushing, giving the product a more premium appearance.

Laser Brushing

Laser brushing is one of the most advanced brushing technologies. It uses high-energy laser beams to etch precise brushed textures onto the aluminium surface. This method allows for complex, customised texture designs and offers extremely high processing precision.

Laser brushing is mainly used in the fields of high-end custom metal accessories, nameplates, and artwork, providing products with a unique visual effect. However, the equipment for this process is relatively expensive, making it suitable for the high-end market.

Summary

• Conco currently has 20 traditional brushing machines, suitable for processing most aluminium products. We also have 10 abrasive belt and other brushing machines. In recent years, we have upgraded most of our equipment, significantly improving processing efficiency. Additionally, our skilled craftsmen have many years of experience in the processing techniques, allowing us to offer professional services and solutions to any issues.