1. Purpose of Sample Processing

Sample processing is used to:

• Verify that blasting or peening parameters (air pressure, nozzle distance, media type, flow rate, etc.) produce the intended surface finish.

• Calibrate equipment and process variables before full-scale production.

• Develop process documentation (Standard Operating Procedures or Work Instructions).

• Provide data for quality assurance, traceability, and certification (especially in aerospace, defense, and automotive industries).

2. Sample Preparation

Before processing, the sample — typically a piece of the same material as the production part — is prepared to a controlled condition:

• Cleaning: Removal of oil, rust, or coatings.

• Masking: Protecting areas not to be blasted or peened.

• Fixture Setup: Mounting samples to replicate the orientation and exposure of production parts.

3. Blasting or Peening Operation

During processing, the sample is subjected to the same media and conditions as intended for production:

• Abrasive Blasting: Uses air-driven media (e.g., steel grit, aluminum oxide, glass beads) to clean, etch, or roughen surfaces.

• Shot Peening: Uses spherical media (steel shot, ceramic, glass) to induce beneficial compressive stress that improves fatigue life.

Operators measure and record:

• Air pressure at the nozzle.

• Media type, size, and flow rate.

• Nozzle-to-part distance and angle.

• Exposure time and coverage.

4. Post-Processing and Evaluation

After blasting or peening, the sample is analyzed to confirm process effectiveness:

• Surface Roughness: Measured with a profilometer or comparator.

• Almen Intensity (Shot Peening): Assessed using Almen strips to verify energy imparted.

• Cleanliness and Coating Adhesion (Blasting): Evaluated visually or via adhesion testing.

• Residual Stress Measurement (Peening): Checked via X-ray diffraction or layer removal methods.

5. Documentation and Validation

Finally, results are documented in process validation reports or certification records:

• Confirms that process parameters meet specification.

• Establishes baseline for production settings.

• Supports ISO, NADCAP, or customer quality system compliance.