Featured Snippet: Defects/Panel = Holes x (ppm / 1,000,000)
Free PCB drilling first-pass yield calculator. Estimate first-pass yield from defect rate per hole (ppm) and holes per panel, and read a quality class.
Suitable for:
Estimate first-pass yield.
| First-pass yield | -- % |
| Defects / panel | -- |
| Class | -- |
Estimate from your own defect data; ppm covers breakage + burr + void mix.
First-pass yield is the share of panels that drill clean with no defect rework. It falls with defect rate per hole and hole count. Process engineers track it to justify better entry/backup boards and tighter parameters. This tool converts defect ppm and holes/panel into first-pass yield and a class.
Defects come from drill breakage, burr and voids - all reducible with matched parameters and quality boards. A lubricant aluminum entry and UV melamine backup cut wander, burr and breakage, pushing yield above 98% on demanding builds. See our lubricant aluminum page.
| Material | Throughput Impact | Hole Quality | Cost per Panel |
|---|---|---|---|
| UV Melamine backup board | High hit count | Excellent exit burr control | $$$ |
| HDF backup board | Standard hit count | Good burr control | $$ |
| Phenolic backup board | Moderate hit count | Good for back-drill | $ |
| Lubricated aluminum entry | +20-40% stack height | Excellent micro-via quality | $$$ |
| Standard aluminum entry | Baseline | Good universal protection | $$ |
Stable feed rate and clean exits are what let you push hit count without micro-drill breakage. Pair the right board with the parameters from this tool — see our backup board range and aluminum entry boards.
| Material | RPM | Chip load | Feed (m/min) | Entry | Backup |
|---|---|---|---|---|---|
| FR4 (standard multilayer) | 90,000 | 0.012 | 2.16 | Aluminum entry sheet | HDF backup board |
| HDI / micro-via | 110,000 | 0.008 | 1.76 | Lubricant aluminum | UV melamine 880 backup board |
| Rogers (high-frequency) | 80,000 | 0.010 | 1.60 | Aluminum entry sheet | Phenolic backup board |
| PTFE / Teflon | 60,000 | 0.008 | 0.96 | Aluminum entry sheet | Phenolic backup board |
| IC substrate (ABF) | 120,000 | 0.006 | 1.44 | Lubricant aluminum | UV melamine 950 backup board |
| Ceramic PCB | 50,000 | 0.008 | 0.80 | Aluminum entry sheet | Phenolic backup board |
| Aluminum PCB (IMS) | 40,000 | 0.010 | 0.80 | Aluminum entry sheet | Phenolic backup board |
| Copper-core PCB | 30,000 | 0.010 | 0.60 | Aluminum entry sheet | Phenolic backup board |
Figures are qualified starting points cross-checked with published fabrication guidance and supplier benchmarks — validate on your own panels.
First-pass yield (standard)
Representative field benchmarks for a 0.20 mm drill on standard FR4; actual results vary with stackup, machine and consumables — validate on your own panels.
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What is first-pass yield? Share of panels that drill clean with no rework, first time.
What is defect ppm? Defects per million holes; covers breakage, burr and void mix.
What lowers yield? High defect ppm and high hole count both cut first-pass yield.
What is drill breakage? Sudden bit snap that scraps a panel; good support reduces it.
What is burr? Exit burr needing a cleaning step; clean exits raise yield.
How do I raise yield? Match RPM/feed, use quality entry/backup, keep runout low.
What is a lubricant entry sheet? Coated entry that cools and centres micro-holes, cutting defects.
What is UV melamine 880? High-burr-control backup that lifts yield on fine stacks.
What is via reliability? Long-term via integrity; clean drilling supports it.
What is desmear? Removing resin smear after drilling to restore the hole wall.
What is hole wall roughness? Rough walls can trap chemistry and lower yield after plating.
What is the cost of low yield? Rework and scrap erase the savings from cheap boards.
Cycle time per hole is the sum of feed time (stack height / feed rate), retract time, and table positioning. Throughput (holes/hour) is the inverse of cycle time multiplied by spindle count. A move from 2-up to 3-up stacking can increase throughput by 50% — if the entry board supports it.
Excellon — PCB drilling machines ↗
Panel drilling cost = (drill bit cost + entry board cost + backup board cost + machine time cost + overhead) ÷ good panels out. Scrap from drilling defects often dominates the cost equation. Reducing breakage and burr defects through better consumable selection frequently pays for itself within weeks.
IPC — PCB cost factors (IPC-2221) ↗
First-pass yield in drilling is driven by positional accuracy, hole wall quality, and burr height. Defect rate calculators on this site help model the impact of parameter shifts. A 1% improvement in yield on high-layer-count boards can save thousands of dollars per month.
Sierra Circuits — Back-drilling ↗
Spindle utilization (actual drilling time ÷ total shift time) is the key machine efficiency metric. Unplanned downtime for drill breakage (15–45 min per event) is the largest utilization killer. Consistent consumable quality reduces breakage frequency and improves OEE.
Posalux — PCB drilling solutions ↗
Back-drilling requires controlled-depth accuracy ±0.05 mm to remove the stub without damaging the target layer. The entry board choice matters: a dedicated back-drill entry sheet with coating provides consistent Z-reference for depth registration and protects the surface from the larger back-drill bit.
YUESHAN — Back-drill depth control guide
Drill resharpening can recover 60–80% of original tool life at 30–50% of new bit cost. The decision to resharpen depends on the number of regrinds possible (typically 3–5 for micro-drills) and the quality requirement of the target holes. Resharpening is most economical for standard-diameter drills above 0.3 mm.
Process and CAM engineers use these numbers across demanding builds:
The right entry and backup board is what actually lets you hold a stable feed rate without breakage. Explore the product lines:
HDF, UV melamine and phenolic backup boards for stable exits and burr control.
Product Page →Plain and coated aluminum entry boards, including lubricated grades for micro-holes.
Product Page →Self-lubricating entry sheets that cool and center the bit on HDI / micro-via drilling.
Product Page →Coated back-drill entry sheets built for controlled-depth second-pass accuracy.
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