What parameters should be noted during the shot blasting process in Dalian

Dalian shot blasting is a surface treatment process that uses high-speed metal shot material to clean, strengthen, or shape the surface of a workpiece. To achieve ideal processing results, the following parameters must be strictly controlled:

1、 Pill material parameters

1. Pill material

The material of the pellet directly affects the processing effect and the surface quality of the workpiece. Common pill ingredients include:

Cast steel shot: Moderate hardness (HRC40-50), suitable for most metal surface treatments

Stainless steel shot: Strong corrosion resistance, used for special materials such as stainless steel and aluminum alloy

Glass beads: low hardness, used for precision parts and in situations where surface hardening is avoided

Ceramic pellets: high hardness, used for special strengthening treatment

2. Pill size

The diameter range of the pellet material is usually between 0.1-3.0mm, and the selection criteria are:

Small size pellets (0.1-0.3mm): used for precision parts, thin-walled parts, or workpieces requiring low surface roughness

Medium sized pellets (0.3-1.0mm): universal type, suitable for most conventional treatments

Large size pellets (1.0-3.0mm): used for heavy workpieces or occasions that require deep cleaning

3. Pill shape

Circular pellets: generate uniform impact force, suitable for surface strengthening

Irregular shaped pellets: Strong cutting ability, suitable for surface cleaning

Mixed shape: Balancing cleaning and strengthening effects

2、 Equipment parameters

1. Type of shot blasting machine

Drum type shot blasting machine: suitable for batch processing of small parts

Suspended shot blasting machine: suitable for large and medium-sized workpieces

Through type shot blasting machine: used for continuous production lines

Shot blasting room: used for large or special shaped workpieces

2. Head throwing parameters

Number of throwing heads: configured according to the size of the workpiece and processing requirements

Head throwing speed: usually 2000-4000rpm, the higher the speed, the greater the impact force

Throwing angle: Adjustable angle affects the uniformity of pellet coverage

3. Conveyor system

Conveyor speed: affects processing time and coverage uniformity

Workpiece rotation speed: Ensure uniform processing in all directions

3、 Process parameters

1. Projection speed

Usually controlled within the range of 50-100m/s

Excessive speed may cause deformation or surface damage to the workpiece

If the speed is too low, it will affect the processing effect and efficiency

2. Projection angle

A better angle is usually 30-60 degrees

Too small an angle affects the cleaning effect

Excessive angle may cause excessive surface deformation

3. Processing time

Determine based on the material, surface condition, and processing requirements of the workpiece

Insufficient processing due to too short a time

Excessive time may cause surface hardening or dimensional changes

4. Coverage rate

Defined as the percentage of pellet material covering the surface of the workpiece

Generally required to achieve coverage rate

Special applications may require a coverage rate of 200% or higher

4、 Environmental parameters

1. Temperature control

Ideal working temperature 10-40 ℃

Excessive temperature affects equipment performance and pellet life

Low temperature may cause condensation and corrosion problems

2. Humidity control

The relative humidity should be controlled within the range of 30-70%

Excessive humidity leads to clumping of pellets and rusting of workpieces

Excessive dust generated by low humidity

3. Ventilation system

Ensure sufficient air exchange rate

Maintain the dust concentration in the work area within a safe range

Prevent the accumulation of harmful gases

5、 Quality control parameters

1. Surface roughness

Expressed as Ra value, it is usually controlled between 0.8-12.5 μ m

Affects subsequent coating adhesion and appearance quality

By adjusting the size of the pellet and the ejection parameters

2. Surface cleanliness

Meet Sa2.5 or Sa3 level standards

No visible pollutants such as grease, oxide skin, rust, etc

Evaluate through visual inspection or specialized testing equipment

3. Residual stress

The distribution of compressive stress generated by shot blasting strengthening

Measure using X-ray diffraction or strain gauges

Ensure that the required stress values are achieved within the expected depth range

6、 Safety parameters

1. Equipment protection

Ensure that all protective devices are in good condition

Regularly inspect vulnerable parts such as throwing heads and protective plates

Keep the emergency stop system functioning properly

2. Dust control

The dust concentration in the work area is below 5mg/m ³

Regularly clean the dust collection system

Prevent the risk of dust explosion

3. Noise control

The noise level in the work area should be below 85dB

Adopting sound insulation measures and ear protection

Regular maintenance to reduce equipment operating noise

7、 Maintain parameters

1. Pill replenishment cycle

Regularly replenish new pill materials based on processing capacity

Maintain a stable mixing ratio of pellets

Timely remove broken pellets and dust

2. Equipment lubrication

Regularly lubricate according to the manufacturer's requirements

Use specified type of lubricating oil

Monitor the working status of the lubrication system

3. Replacement of vulnerable parts

Establish a record of key component replacement

Replace in a timely manner according to the degree of wear and tear

Use original or certified replacement parts

8、 Special material processing parameters

1. Aluminum alloy treatment

Use stainless steel pellets or glass beads

Reduce projectile velocity and pressure

Shorten processing time to prevent overheating

2. Titanium alloy treatment

Strictly control the cleanliness of the pill material

Using specialized iron free pollution pellets

Clean the surface promptly after processing

3. Composite material processing

Choose appropriate pellets to avoid fiber damage

Accurately control the ejection angle

Adopting segmented processing technology

9、 Parameter optimization method

1. Design of Experiments (DOE)

Determine better parameter combinations through orthogonal experiments

Analyze the interactive effects of various parameters

Establish a parameter effect response model

2. Process monitoring

Real time monitoring of key parameter fluctuations

Establish SPC control chart

Timely adjust deviation parameters

3. Continuous improvement

Regularly evaluate the process effect

Collect production data for analysis

Implement progressive optimization

By controlling the above parameters through the system, it is possible to ensure the stability and reliability of the shot blasting process, obtain consistent surface treatment quality, while improving production efficiency and reducing costs. Different workpieces and application scenarios require targeted adjustment of parameter combinations. It is recommended to conduct sufficient process validation and parameter optimization before actual production.