تحليل تقنية السفع بحبيبات الألومنيوم

What is aluminium surface sandblasting?

• التعريف

Aluminium surface sandblasting is a mechanical processing technique that uses high-speed abrasive particles to impact the surface of aluminium. It removes the oxide layer, dirt, old coatings, or other impurities from the surface, achieving a clean, roughened surface or improving its appearance. Additionally, it can enhance the material’s mechanical properties and the effectiveness of subsequent processes.

• Principle

The sandblasting process accelerates abrasive particles using airflow or mechanical force and sprays them onto the aluminium surface. When the abrasive particles impact the aluminium surface at high speed, they generate physical shock and friction, resulting in the following effects:

• Cleaning: Removing surface oxide scales, corrosion, grease, or old coatings.
• Modification: Adjusting surface roughness to increase adhesion for coatings or bonding materials.
• Beautification: Creating a uniform texture or glossy effect on the surface.

Detailed Explanation of the Sandblasting Process

The Basic Process of Sandblasting:

Surface Pre-treatment
Before sandblasting, preliminary treatment of the workpiece is necessary to ensure the effectiveness of the process:

• Cleaning Surface Impurities
  1. Use solvents or cleaners to remove grease, dirt, and other contaminants.
  2. Ensure the surface is free from loose oxides or visible corrosion.
• Inspecting the Workpiece
  1. Determine whether sensitive areas (such as threaded holes or critical contact surfaces) must be masked to prevent damage from sandblasting.
  2. Mark areas requiring special processing.

Sandblasting Operation
This is the core step of the sandblasting process, which determines the effectiveness of the sandblasting on the product. The following is a brief introduction:

• Starting the Operation
  1. Start the equipment and gradually adjust the sandblasting pressure to the set value, avoiding excessive impact on the workpiece surface.
• Uniform Spraying
  1. Spray evenly at the set angle (usually between 45° and 90°) and distance (typically 100-200 mm), covering the entire surface.
  2. Maintain a constant moving speed to prevent over-spraying a particular area.
• Detail Adjustments
  1. For complex areas or detailed sections, use a small-diameter nozzle or reduce the spraying pressure for finer treatment.

Cleaning and Inspection
After sandblasting, surface cleaning and quality inspection are required:

• Removing Residues
  1. Use compressed air or a brush/vacuum system to remove any remaining abrasives and dust from the surface.
• Inspecting Surface Quality
  1. Check whether the desired level of cleanliness and roughness has been achieved.
  2. Ensure the surface is free from visible defects, such as dents, scratches, or areas that have not been properly cleaned.

Post-treatment
After sandblasting, the workpiece requires further treatment to ensure quality and performance:

• Anti-oxidation Protection
  1. Immediately apply a protective coating (such as primer or sealant) to prevent the exposed aluminium surface from oxidising again after sandblasting.
• Preparation for Subsequent Processes
  1. If further processing (such as painting, plating, or welding) is required, the sandblasted surface provides a good foundation for adhesion.

Commonly Used Sandblasting Equipment

Sandblasting equipment can be categorised into various types based on their working principles and application scenarios. Below are the commonly used sandblasting equipment, along with their characteristics and areas of application:

Pressure Sandblasting Machine

• Working Principle
  Compressed air is used to propel abrasives through the nozzle, which are then sprayed onto the workpiece surface, generating impact and friction to complete the surface treatment.
• Features
  1. Adjustable blasting pressure, suitable for different workpieces and material requirements.
  2. Fast abrasive flow, resulting in high sandblasting efficiency.
  3. Ideal for large-area surface cleaning and roughening.
• سيناريوهات التطبيق
  1. Surface treatment of large workpieces (such as aluminium plates and aluminium structural components).
  2. Removal of thick oxide layers, corrosion, and old coatings.

Suction Sandblasting Machine

• Working Principle
  Abrasives are drawn into the nozzle by vacuum suction, and then accelerated by compressed air to be sprayed onto the workpiece surface.
• Features
  1. Simple structure, with relatively low equipment cost.
  2. Lower abrasive flow rate, suitable for light surface treatment.
  3. Easy operation, but relatively lower efficiency.
• سيناريوهات التطبيق
  1. Surface cleaning and polishing of small components.
  2. Fine sandblasting work, ideal for thin-walled aluminium parts or complex-shaped workpieces.

Centrifugal Shot Blasting Machine

• Working Principle

The abrasive is accelerated and projected onto the workpiece surface by a high-speed rotating impeller, without the need for compressed air as a power source.

• Features

1. High abrasive utilisation with lower operational costs.
2. Even blasting intensity is suitable for mass production.
3. High degree of automation, compatible with assembly line operations.

التطبيقات

1. Mass processing of aluminium components, such as automotive parts and mechanical fittings.
2. Surface cleaning and strengthening of workpieces requiring high repeatability.

Wet Blasting Machine

• Working Principle

The abrasive is mixed with water and sprayed onto the workpiece surface using a spray gun, with the water flow providing the impact for the treatment.

• Features

1. Reduces dust pollution, making the working environment more user-friendly.
2. Enables polishing and fine surface treatment, avoiding excessive heat and friction damage.
3. Lower abrasive consumption, ideal for high-precision surface treatments.

• التطبيقات

1. Processing of aluminium products requiring high gloss surfaces (e.g., decorative aluminium parts).
2. Surface polishing and cleaning of precision aluminium components.

Automated Shot Blasting Machine

• Working Principle

The shot blasting process is automated through the use of robots or mechanical arms.

• Features

1. Increases production efficiency and reduces human error.
2. Capable of multi-angle shot blasting for complex workpieces.
3. Programmable control, suitable for high-precision and consistent requirements.

• التطبيقات

1. High-end industrial sectors such as aerospace and precision manufacturing.
2. Products in large-scale mass production where surface treatment consistency is critical.

Manual Shot Blasting Equipment

• Working Principle

The workpiece surface is treated by a hand-held spray gun, with the operator manually controlling the direction, pressure, and distance.

• Features

1. Suitable for scenarios requiring high flexibility.
2. Requires a high level of skill from the operator, with lower efficiency compared to automated equipment.

• التطبيقات

1. Surface treatment for small batch production or workpieces with specific shapes.
2. Repairing localised defects on aluminium products or removing detailed imperfections.

Shot Blasting Room

• Working Principle

Within a closed shot blasting room, workpieces are processed either in a fixed or movable manner, with abrasives being recycled through a recovery system.

• Features

1. Suitable for comprehensive treatment of large workpieces.
2. Environmentally friendly, with recyclable abrasives and effective dust control.

• التطبيقات

1. Surface cleaning and roughening of large aluminium alloy sheets or components.
2. Surface treatment of large equipment in industries such as aerospace and shipbuilding.

summary table

Currently, Conco Company has a fully automated sandblasting production line. In our production workshop, we are also equipped with manual sandblasting equipment and a specialised sandblasting room to meet the diverse needs and requirements of our customers. We have many years of sandblasting experience and a team of skilled craftsmen for surface processing. Additionally, we are equipped with several inspection devices and conduct random quality checks on our products to ensure timely delivery while maintaining high product quality.

Applicable Sandblasting Materials

The choice of sandblasting materials (abrasives) directly impacts the sandblasting effect, surface quality, and processing efficiency. Below are common sandblasting materials along with their characteristics and application scenarios:

• Silica Sand

الخصائص

• Moderate hardness, cost-effective.
• Abrasive particles are uniform, providing stable sandblasting results.
• Produces a considerable amount of dust during use, requiring enhanced dust control measures.

التطبيقات

• Removal of oxide layers, rust, and light coatings.
• Surface roughening, preparing the substrate for subsequent painting and plating.
• Not suitable for high-precision tasks or applications with strict environmental requirements.

• Glass Beads

الخصائص

• Smooth surface, moderate density, relatively low hardness.
• Causes minimal wear on the workpiece, suitable for delicate processing.
• Reusable, with strong durability.

التطبيقات

• Surface polishing and decorative finishing of aluminium parts, providing a uniform matte effect.
• Suitable for workpieces that require cleaning without altering dimensions.
• Used in industries such as aerospace and medical equipment, where high surface quality is essential.

• Brown Fused Alumina

الخصائص

• High hardness, excellent wear resistance, and strong sharpness.
• High chemical stability, minimising contamination of the workpiece surface.
• Produces less dust, offering better environmental performance.

التطبيقات

• Deep surface cleaning, removing thick oxide layers, rust, or welding slag.
• Surface roughening to enhance adhesion for coatings and plating.
• Suitable for industrial scenarios requiring efficient processing, such as machining mechanical parts.

• White Fused Alumina

الخصائص

• Higher hardness than brown fused alumina, with greater purity and fewer impurities.
• Clean surface, leaving no harmful residues on the workpiece.
• Suitable for applications that require extremely high surface quality.

التطبيقات

• High-precision surface treatment, used for machining precision aluminium parts.
• Ideal for surface polishing of medical devices, electronic components, and decorative items.

• Stainless Steel Shot

الخصائص

• High strength, wear-resistant, and has a high reuse rate.
• Strong impact on the workpiece surface, enabling strengthening treatment.
• Resistant to rust after surface treatment, suitable for high-performance metal components.

التطبيقات

• Enhances the surface strength and fatigue resistance of aluminium parts.
• Cleans and strengthens aluminium alloy castings, forgings, and other mass-produced workpieces.
• No need for additional cleaning after surface treatment, making it ideal for high-efficiency production lines.

• Ceramic Beads

الخصائص

• High hardness, high temperature resistance, and wear resistance.
• Produces a relatively low amount of dust during sandblasting.
• No contamination to the surface, suitable for fine work.

التطبيقات

• Surface finishing of high-end aluminium products, providing a satin effect.
• Used in high-demand industries such as aerospace, automotive, and medical equipment.

• Plastic Granules

الخصائص

• Lower hardness, good elasticity, causing minimal damage to the workpiece surface.
• Lightweight, suitable for removing coatings without affecting the base material of the workpiece.

التطبيقات

• Removal of paint and coatings from the surface of aluminium products without damaging the substrate.
• Suitable for processing lightweight materials such as thin-walled aluminium parts and electronic product housings.

• Steel Grit and Steel Shot

الخصائص

• High hardness, strong impact, suitable for heavy-duty cleaning tasks.
• Steel shot has a smooth surface, used for strengthening treatment; steel grit has an irregular shape, ideal for surface cleaning and roughening.

التطبيقات

• Removal of scale, heavy rust, or coatings.
• Surface strengthening of aluminium parts, enhancing fatigue strength.
• Not suitable for thin-walled aluminium parts, as it may cause deformation.

• Natural Sand (River Sand, Sea Sand)

الخصائص

• Economical, but with uneven hardness and purity.
• Prone to dust pollution, not environmentally friendly.

التطبيقات

• Low-cost surface treatment, suitable for workpieces with less demanding requirements.
• Typically used in cleaning or polishing scenarios where high standards are not necessary.

• Silicon Carbide

الخصائص

• Extremely high hardness and sharpness, with stable chemical properties.
• Ideal for high-intensity cleaning tasks.

التطبيقات

• Effective for deep cleaning stubborn dirt, corrosion, and weld spatter from aluminium surfaces.
• Suitable for processing super-hard metals or high-temperature resistant aluminium parts.

Abrasive Selection Reference Table

Common Issues and Solutions in Sandblasting Aluminium

During the sandblasting process of aluminium, some issues may arise that affect the surface quality or processing efficiency of the workpieces. Below are the common problems and their solutions:

• Uneven Surface Roughness

Cause Analysis:

• Unstable sandblasting pressure.
• Uneven size or shape of abrasive particles.
• Inconsistent movement speed or distance of the sandblasting gun.

Solution:

• Adjust the sandblasting equipment to ensure stable pressure.
• Use abrasives with consistent quality and regularly replace aged abrasives.
• Standardise the sandblasting process to maintain a uniform gun speed and appropriate distance.

• Scratches or Pits on the Surface After Sandblasting

Cause Analysis:

• Use of excessively hard abrasives or too large abrasive particles.
• Sandblasting pressure is too high, resulting in excessive impact force.
• Sandblasting time is too long, causing excessive wear on the surface material.

Solution:

• Choose abrasives with moderate hardness (e.g., glass beads or fine-grit abrasives).
• Reduce sandblasting pressure, especially when processing thin-walled aluminium parts.
• Control sandblasting time to avoid over-treatment.

• Colour Difference on the Surface After Sandblasting

Cause Analysis:

• Inappropriate replacement of abrasives or changes in specifications.
• Uneven blasting due to nozzle wear during the sandblasting process.
• Inconsistent surface material or oxidation level of the aluminium itself.

Solution:

• Ensure the use of consistent abrasives and regularly check the condition of the nozzles.
• Pre-treat the aluminium surface to homogenise the oxide layer and impurities.
• Adjust sandblasting parameters to suit different types of aluminium materials.

• Surface Deformation of Workpieces

Cause Analysis:

• Sandblasting pressure is too high or abrasive impact force is excessive.
• Aluminium parts are too thin or structurally unstable.

Solution:

• Reduce sandblasting pressure and choose abrasives with lower hardness (e.g., plastic pellets or fine glass beads).
• Support and secure thin-walled aluminium parts to reduce the risk of deformation.
• Use short, multiple light blasts instead of long, high-intensity spraying.

• Insufficient Surface Adhesion After Sandblasting

Cause Analysis:

• Surface roughness does not meet the requirements for subsequent processes.
• Incomplete sandblasting cleaning, leaving residual abrasives or impurities.

Solution:

• Adjust the type and particle size of the abrasives to achieve the appropriate roughness.
• Clean the surface after sandblasting to ensure it is free of residues.
• Optimise parameters for subsequent coating or electroplating processes.