test cost
**Test cost** is the **expense of electrically testing each device** — including equipment, labor, facilities, and materials, typically $0.10-$2.00 per device, representing 5-20% of total manufacturing cost and a major target for cost reduction efforts.
**What Is Test Cost?**
- **Definition**: Total cost to test one device.
- **Typical**: $0.10-$2.00 per device depending on complexity.
- **Components**: Equipment, labor, facilities, consumables.
- **Impact**: 5-20% of total manufacturing cost.
**Why Test Cost Matters**
- **Profitability**: Significant portion of manufacturing cost.
- **Competitiveness**: Lower test cost improves margins or enables lower prices.
- **Volume**: High-volume products amplify test cost impact.
- **Optimization**: Major opportunity for cost reduction.
**Cost Components**
- **Equipment**: Tester depreciation and maintenance (40-60%).
- **Labor**: Test operators and engineers (20-30%).
- **Facilities**: Cleanroom space, utilities (10-20%).
- **Consumables**: Probe cards, sockets, handlers (5-10%).
- **Yield Loss**: Cost of overkill and escapes (5-15%).
**Calculation**
```python
def calculate_test_cost(tester_cost_per_hour, test_time_seconds,
labor_rate, overhead_rate):
# Equipment cost
equipment_cost = (tester_cost_per_hour / 3600) * test_time_seconds
# Labor cost (per device)
labor_cost = (labor_rate / 3600) * test_time_seconds
# Overhead
overhead = (equipment_cost + labor_cost) * overhead_rate
total_cost = equipment_cost + labor_cost + overhead
return total_cost
# Example
cost = calculate_test_cost(
tester_cost_per_hour=500,
test_time_seconds=5,
labor_rate=50,
overhead_rate=0.3
)
print(f"Test cost: ${cost:.3f} per device")
```
**Reduction Strategies**
- **Reduce Test Time**: Optimize patterns and parallel testing.
- **Increase Utilization**: Maximize tester uptime.
- **Adaptive Testing**: Skip unnecessary tests.
- **Automation**: Reduce labor content.
- **Yield Improvement**: Reduce retest and rework.
**Trade-offs**: Lower test cost must be balanced against quality (coverage) and yield (overkill vs escapes).
Test cost is **a major profit lever** — optimizing it while maintaining quality is critical for competitive manufacturing economics.