Coverage Rate Concept
Coverage rate is the percentage of workpiece surface hit by shot blasting. Higher coverage means more uniform strengthening effect.
Standard Requirements
- Surface strengthening: Coverage ≥98% (visual full coverage)
- Surface cleaning: Coverage ≥95%
- Precision strengthening: Coverage ≥100% (over-coverage)
Calculation Methods
Visual Method
Compare with standard coverage sample:
- 98% coverage:几乎 no original surface visible
- 95% coverage: Some original surface visible
Formula Calculation
Coverage C = 1 - e^(-k × t × n)
Where:
- k: Shot intensity factor
- t: Blasting time
- n: Hits per unit area
Simplified Estimation
Coverage vs blasting time:
- 50% coverage: Baseline time t₀
- 98% coverage: ~4 × t₀
- 100% coverage: ~6 × t₀
Improving Coverage
Parameter Adjustment
- Increase blasting time: Most direct method
- Increase shot flow: More hits per unit time
- Optimize blaster position: Reduce blind spots
- Rotate workpiece: Ensure uniform treatment
Equipment Factors
- Number and layout of blasters
- Conveyor speed
- Shot size selection
Common Issues
Reasons for inadequate coverage
- Insufficient blasting time
- Reduced blaster power (blade wear)
- Incorrect workpiece positioning
- Unstable shot flow
Solutions
- Extend blasting time or add blasters
- Replace worn blades promptly
- Optimize workpiece placement
- Check and stabilize shot supply system
Process Optimization: We provide process parameter consulting based on your equipment and workpiece requirements.
