The economics of x-rays
Staff -- Test & Measurement World, 2/1/2001
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Download tables as an Excel spreadsheet, | TABLE 1A Simple PCB (no scrap) | ||||
| Without x-ray inspection | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 80,000 | |||
| Faulty PCBs | 20,000 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| ICT coverage | 80% | 16,000 | $10 | $160,000 |
| Functional coverage | 15% | 3,000 | $25 | $75,000 |
| System-test coverage | 5% | 1,000 | $100 | $100,000 |
| Total repaired | 100% | 20,000 | $335,000 | |
| With x-ray inspection | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 80,000 | |||
| Faulty PCBs | 20,000 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| X-ray coverage | 93% | 18,600 | $10 | $186,000 |
| Functional coverage | 5% | 1,000 | $25 | $25,000 |
| System-test coverage | 2% | 400 | $100 | $40,000 |
| Total repaired | 100% | 20,000 | $251,000 | |
| One-year benefit | $84,000 | |||
| TABLE 2A Complex SMT PCB (no scrap) | ||||
| Without x-ray inspection | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 60,000 | |||
| Faulty PCBs | 40,000 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| ICT coverage | 60% | 24,000 | $10 | $240,000 |
| Functional coverage | 35% | 14,000 | $25 | $350,000 |
| System-test coverage | 5% | 2,000 | $100 | $200,000 |
| Total repaired | 100% | 40,000 | $790,000 | |
| With x-ray inspection | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 60,000 | |||
| Faulty PCBs | 40,000 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| X-ray coverage | 93% | 37,200 | $10 | $372,000 |
| Functional coverage | 5% | 2,000 | $25 | $50,000 |
| System-test coverage | 2% | 800 | $100 | $80,000 |
| Total repaired | 100% | 40,000 | $502,000 | |
| One-year benefit | $288,000 | |||
| TABLE 2B Complex SMT PCB (no scrap) | ||||
| Without x-ray inspection | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 60,000 | |||
| Faulty PCBs | 40,000 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| ICT coverage | 60% | 24,000 | $10 | $240,000 |
| Functional coverage | 35% | 14,000 | $25 | $350,000 |
| System-test coverage | 5% | 2,000 | $100 | $200,000 |
| Total repaired | 100% | 40,000 | $790,000 | |
| With x-ray inspection and production feedback | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 85,000 | |||
| Faulty PCBs | 15,000 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| X-ray coverage | 81% | 12,200 | $10 | $122,000 |
| Functional coverage | 13% | 2,000 | $25 | $50,000 |
| System-test coverage | 6% | 800 | $100 | $80,000 |
| Total repaired | 100% | 15,000 | $252,000 | |
| One-year benefi t | $538,000 | |||
| TABLE 3 Simple PCB with 1.5% scrap | ||||
| Without x-ray inspection | ||||
| Total PCBs produced | 101,523 | |||
| Actual PCB yield | 81,218 | |||
| Faulty PCBs | 20,305 | |||
| Scrap PCBs | 1,523 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| ICT coverage | 80% | 16,244 | $10 | $162,440 |
| Functional coverage | 15% | 3,046 | $25 | $76,150 |
| System-test coverage | 5% | 1,015 | $100 | $101,500 |
| Total repaired | 100% | 20,305 | $340,090 | |
| Add scrap cost of $300/PCB for 1,523 PCBs | $456,900 | |||
| Total cost | $796,990 | |||
| With x-ray inspection | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 80,000 | |||
| Faulty PCBs | 20,000 | |||
| Scrap | 0 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| X-ray coverage | 93% | 18,600 | $10 | $186,000 |
| Functional coverage | 5% | 1,000 | $25 | $25,000 |
| System-test coverage | 2% | 400 | $100 | $40,000 |
| Total repaired | 100% | 20,000 | $251,000 | |
| One-year benefit | $545,990 | |||
| TABLE 4A Complex SMT PCB with 1.5% scrap | ||||
| Without x-ray inspection | ||||
| Total PCBs produced | 101,523 | |||
| Actual PCB yield | 60,914 | |||
| Faulty PCBs | 40,609 | |||
| Scrap PCBs | 1,523 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| ICT coverage | 60% | 24,366 | $10 | $243,660 |
| Functional coverage | 35% | 14,213 | $25 | $355,325 |
| System-test coverage | 5% | 2,030 | $100 | $203,000 |
| Total repaired | 100% | 40,609 | $801,985 | |
| Add scrap cost of $300/PCB for 1,523 PCBs | $456,900 | |||
| Total cost | $1,258,885 | |||
| With x-ray inspection | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 60,000 | |||
| Faulty PCBs | 40,000 | |||
| Scrap PCBs | 0 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| X-ray coverage | 93% | 37,200 | $10 | $372,000 |
| Functional coverage | 5% | 2,000 | $25 | $50,000 |
| System-test coverage | 2% | 800 | $100 | $80,000 |
| Total repaired | 100% | 40,000 | $502,000 | |
| One-year benefit | $756,885 | |||
| TABLE 4B Complex SMT PCB with 1.5% scrap | ||||
| Without x-ray inspection | ||||
| Total PCBs produced | 101,523 | |||
| Actual PCB yield | 60,914 | |||
| Faulty PCBs | 40,609 | |||
| Scrap PCBs | 1,523 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| ICT coverage | 60% | 24,366 | $10 | $243,660 |
| Functional coverage | 35% | 14,213 | $25 | $355,325 |
| System-test coverage | 5% | 2,030 | $100 | $203,000 |
| Total repaired | 100% | 40,609 | $801,985 | |
| Add scrap cost of $300/PCB for 1,523 PCBs | $456,900 | |||
| Total cost | $1,258,885 | |||
| With x-ray inspection and production feedback | ||||
| Total PCBs produced | 100,000 | |||
| Actual PCB yield | 85,000 | |||
| Faulty PCBs | 15,000 | |||
| Scrap PCBs | 0 | |||
| Faults found by: | Percent of Total | PCBs | Cost per repair | Repair cost |
| X-ray coverage | 81% | 12,200 | $10 | $122,000 |
| Functional coverage | 13% | 2,000 | $25 | $50,000 |
| System-test coverage | 6% | 800 | $100 | $80,000 |
| Total repaired | 100% | 15,000 | $252,000 | |
| One-year benefit | $1,006,885 | |||
