What are the key parameters controlled in automated shot blasting?

In automated shot blasting, several key parameters are precisely controlled to ensure optimal surface treatment and part quality. These parameters include:

1. Blast Distance

The linear distance from the nozzle to the workpiece surface is crucial. A proper distance ensures effective surface scouring while avoiding excessive compressive stress on the workpiece. Typically, this distance is controlled within 100–300 mm.

2. Blast Angle

The angle between the abrasive jet axis and the workpiece surface affects the efficiency and uniformity of the treatment. Angles between 60–75 degrees are recommended to avoid embedding abrasive particles into the surface.

3. Abrasive Type and Particle Size

The choice of abrasive material (e.g., steel shot, glass beads, or garnet) and its particle size significantly impact the surface finish. Smaller particles produce a smoother finish, while larger particles are more aggressive. The selection depends on the desired surface roughness and application requirements.

4. Air Pressure

Air pressure affects the speed and impact force of the abrasive particles. Higher pressures increase the effectiveness of the process but must be adjusted based on the workpiece material and desired surface roughness. Typical ranges are 0.3–0.5 MPa for pressure blasting and 0.5–0.6 MPa for suction blasting.

5. Nozzle Aperture

The diameter of the blast nozzle affects the air consumption and abrasive output. Larger apertures increase efficiency but must be monitored for wear. Nozzle diameters typically range from 8–15 mm.

6. Blast Wheel Speed

In centrifugal wheel blasting, the speed of the blast wheel is a critical parameter. Higher speeds increase the kinetic energy of the abrasive particles, enhancing cleaning efficiency.

7. Conveyor Speed

For automated systems, the speed of the conveyor belt affects the dwell time of the workpiece under the blast stream. Proper control ensures uniform coverage and consistent surface treatment.

8. Abrasive Flow Rate

The rate at which abrasive is fed into the blast stream is carefully controlled to ensure consistent surface treatment. This parameter is particularly important in high-volume production.

9. Blast Pattern and Coverage

Automated systems use advanced controls to ensure uniform blast coverage, avoiding over-blasting or under-blasting. This is critical for achieving consistent surface roughness and quality.

10. Digital Control and Monitoring

Modern automated shot blasting systems integrate digital controls and sensors to monitor and adjust parameters in real-time. This ensures repeatable results and allows for quick adjustments to maintain surface quality.

Conclusion

By precisely controlling these parameters, automated shot blasting systems achieve high-quality surface treatment with consistent results. This level of control is particularly important in industries like aerospace, where surface quality directly impacts part performance and safety