How to clean residual steel shot after shot blasting in Dalian

1、 Reasons for residual steel shot after shot blasting in Dalian

Shot blasting is a common surface treatment process that uses high-speed spraying of steel balls or other abrasives to clean, strengthen, or shape the surface of the workpiece. However, after processing, there are often residual steel balls on the surface and inside of the workpiece, mainly due to:

Workpiece structure complexity: Workpieces with complex internal cavities, holes, or threaded structures are more prone to residual steel shot

Improper selection of steel shot size: When the diameter of the steel shot does not match the characteristic size of the workpiece, it is easy to get stuck

Unreasonable shot blasting process parameters: Improper shooting angle, time, and strength may lead to steel shot embedding

Material issue of steel shot: Poor quality steel shot is prone to breakage and produces small residues

Surface condition of workpiece: rough or oily surfaces are more likely to retain steel balls

2、 The importance of cleaning up residual steel balls

Failure to thoroughly clean the residual steel shot after shot blasting may result in the following issues:

Impact on subsequent processing: Residual steel balls can damage cutting tools, grinding tools, etc

Reduced product performance: Residual steel shot may cause assembly difficulties or affect the functionality of moving parts

Safety hazard: Loose steel balls may fall off, causing equipment damage or personnel injury

Impact on surface treatment quality: Residual steel shot can affect the subsequent surface treatment effects such as electroplating and spraying

Increased maintenance costs: Residual steel shot accelerates equipment wear, increases maintenance frequency and costs

3、 Mechanical cleaning methods

1. Compressed air blowing

Use high-pressure compressed air (0.6-0.8MPa) to blow the surface and inner cavity of the workpiece:

Suitable for most metal workpieces

Different shapes of nozzles need to be matched to adapt to the structure of the workpiece

Wear protective goggles and earplugs during operation

For deep holes or complex structures, multiple blowouts may be required

2. Vibration screening

Place the workpiece on a vibrating screen or table:

Remove residual steel balls through mechanical vibration

Suitable for small, batch processed workpieces

Can be used in conjunction with a sieve to collect and recycle steel balls

The vibration frequency and time need to be adjusted according to the characteristics of the workpiece

3. Magnetic separation

Using permanent magnets or electromagnetic devices to adsorb steel balls:

Specially suitable for cleaning magnetic steel balls

Special magnetic rods can be designed for internal cavity cleaning

High efficiency and no damage to the workpiece

Regularly clean the steel balls adsorbed on the magnetic poles

4. Centrifugal cleaning

Place the workpiece into the centrifuge and rotate it at high speed:

Using centrifugal force to eject residual steel balls

Suitable for small precision parts

Speed needs to be controlled to prevent workpiece deformation

Usually used in conjunction with other methods

4、 Physical and chemical cleaning methods

1. Ultrasonic cleaning

Immerse the workpiece in the cleaning solution and apply ultrasonic waves:

Ultrasonic cavitation can loosen and clamp steel balls

Suitable frequency (20-40kHz) and cleaning solution need to be selected

Significant effect on complex internal cavity structures

May not be suitable for large workpieces

2. Liquid flushing

Rinse with high-pressure water or specialized cleaning solution:

The water pressure is usually 5-15MPa

Rust inhibitor can be added to protect the workpiece

Consider wastewater treatment and steel shot recycling

Better effect on workpieces with severe oil pollution

3. Thermal expansion method

Utilizing the difference in thermal expansion coefficient between steel shot and workpiece material:

Heating the workpiece causes the steel shot to loosen

Temperature control is crucial to avoid affecting the performance of the workpiece

Usually used in conjunction with other cleaning methods

Suitable for specific material combinations

5、 Cleaning techniques for special workpieces

1. Cleaning of threads and inner holes

Use a specialized thread brush or hole brush

Can design magnetic core rod to adsorb inner hole steel balls

Small diameter high-pressure nozzle directional blowing

For blind holes, vacuum suction can be used

2. Cleaning of welded parts and components

Focus on the weld seam area and joint surface

Disassemble and clean separately if possible

Use flexible magnetic strips to adsorb steel balls in hard to reach areas

Extend the blowing or vibration time

3. Cleaning of precision parts

Adopting a multi-stage cleaning process

Using filtered compressed air

Operate in a clean environment

Perform microscopic examination afterwards

6、 Cleaning effect inspection method

Visual inspection: Use a magnifying glass or endoscope to examine key areas

Weighing method: Comparison of weighing before and after cleaning

Magnetic particle testing: perform magnetic particle inspection on suspicious areas

Functional testing: Trial operation of moving parts

Collection method: Collect detached steel balls in subsequent processes

7、 Safety precautions

Operators should wear protective goggles, gloves, and earplugs

High pressure gas source requires installation of pressure regulator and safety valve

Electrical equipment must meet explosion-proof requirements (during wet cleaning)

Establish a steel shot recycling system to prevent environmental pollution

Regularly inspect and clean the integrity of equipment

8、 Steel shot recycling and reuse

Set up a reasonable steel shot collection system

Screening and dust removal treatment of recycled steel balls

Regularly check the particle size and hardness of steel balls

Establish a steel shot usage file and record the number of cycles

Unqualified steel balls should be replaced in a timely manner

9、 Common Problems and Solutions

Steel shot stuck and unable to be cleared: try vibration heating combination method or local disassembly

Rust on the workpiece after cleaning: Immediately rust proof treatment or use rust proof cleaning solution after cleaning

Small steel shot residue: using multi-stage filtered compressed air blowing or ultrasonic assistance

Low cleaning efficiency: optimizing process parameters or designing specialized fixtures

Steel ball contamination cleaning solution: Install magnetic separator or precipitation filtration system

Through the above systematic cleaning methods and precautions, the problem of steel shot residue after shot blasting can be effectively solved, ensuring product quality and production safety. Enterprises should choose appropriate cleaning processes based on their own product characteristics and production conditions, and continuously optimize them to form standardized operating standards.