Featured Snippet: Wear Index = clamp( (RPM/1000 x feed x MaterialAbrasion) / (dia^2 x 50), 1, 10 )
Free PCB drill wear calculator. Estimate a relative wear index from RPM, feed, chip load and material to predict when to resharpen or replace the bit.
Suitable for:
Estimate a relative wear index (1 = low, 10 = high).
| Wear index | -- / 10 |
| Recommendation | -- |
Relative index for comparison only - pair with real hit-count data from your line.
Drill wear is the gradual dulling of the cutting edge that raises heat, burr and hole wall roughness. A simple wear index helps CAM and process engineers compare settings and decide when to resharpen before drill breakage. This tool returns a 1-10 relative index from your RPM, feed, chip load and material.
The index rises with RPM and feed, and with abrasive materials (ceramic, PTFE, Rogers); it falls when a lubricant aluminum entry sheet cools the bit. Treat it as a comparison lever: lower the index by trimming feed or adding lubrication, then confirm with actual hit-count data.
| Material | Feed Stability | Burr Control | Tool Life |
|---|---|---|---|
| UV Melamine backup board | ★★★★★ | ★★★★★ | ★★★★ |
| Phenolic backup board | ★★★★ | ★★★★ | ★★★ |
| Aluminum entry sheet | ★★★★★ | ★★★★★ | ★★★★ |
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.
Wear per hole (0.20 mm drill)
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 drill wear? Drill wear is gradual cutting-edge dulling that raises heat, burr and hole wall roughness over a bit's life.
How is wear measured? In production, wear is measured at the margin (e.g. web thinning); this calculator gives a relative index for comparing settings.
What raises drill wear? High RPM, high feed, small diameter and abrasive materials (ceramic/PTFE/Rogers) all raise wear.
How do I reduce drill wear? Lower feed into the stable band, use matched RPM, add a lubricant entry sheet, keep chips evacuated.
What is drill breakage? Sudden bit snap, often from forcing a worn bit or wrong feed; distinct from gradual wear.
What is resharpening? Restoring the drill point; bits are resharpened several times before retirement.
What is the link between wear and burr? Worn edges tear rather than cut, raising exit burr and nail heading.
What is hole wall roughness? Inside-hole surface roughness; wear increases it and hurts plating quality.
Does a lubricant entry sheet reduce wear? Yes - cooling and centring the bit cuts heat and edge load, lowering the wear index.
What is chip evacuation? Removing swarf from the hole; poor evacuation traps heat and accelerates wear.
What is spindle runout? Radial bit deviation; high runout adds uneven wear and shortens life.
What is the difference between wear and tool life? Wear is the mechanism; tool life is the hole count before resharpening - they move together.
What is drill wander? Lateral bit deflection on entry; wear and poor support worsen it, hurting registration.
What is a good wear index? Below 4 is stable; 4-7 needs monitoring; above 7 means resharpen sooner.
What is via reliability? Long-term hole integrity for plated vias; controlled wear and clean holes support it.
What is desmear? Removing resin smear after drilling to restore the hole wall before plating.
The fundamental relationship — Feed (mm/min) = RPM × chip load × flutes — governs heat generation, burr formation, and tool wear. For micro-drills below 0.2 mm, keep chip load between 0.005–0.012 mm/tooth to avoid drill breakage. Validate on your stack with a sample before committing to production.
Proto-Electronics — PCB drilling process ↗
Stack height and aspect ratio (hole depth ÷ diameter) interact directly with feed parameters. High aspect ratio holes (> 10:1) require reduced feed to maintain chip evacuation and avoid resin smear. Pairing a lubricated entry board with a UV melamine backup board supports higher stacks without quality degradation.
NCAB Group — HDI / microvia design ↗
Tool life is maximised when feed rate keeps the cutting edge loaded (not rubbing). A stable feed of 6–12 mm/min for 0.2 mm drills on FR4 typically yields 3,000–4,000 hits per bit. Worn bits increase burr height and hole wall roughness — monitor both as end-of-life indicators.
IPC — rigid PCB standards (IPC-6012) ↗
The entry board material directly affects parameter stability. Standard aluminum entry sheets provide consistent centering for most builds; lubricated aluminum entry sheets reduce drill wander on micro-vias below 0.15 mm and enable higher feed rates by lowering frictional heat.
YUESHAN — What is an entry board
The backup board absorbs exit energy and controls burr. UV melamine boards (880/950 grades) offer the best surface hardness for HDI and fine-pitch work; HDF is cost-effective for standard FR4; phenolic suits back-drilling and rigid-flex applications.
YUESHAN — What is a backup board
The total cost per hole includes drill bit cost, entry/backup board cost, machine time, and scrap. Optimising parameters to increase hit count by even 20% often has a higher ROI than reducing consumable cost per sheet. Use the tools on this site to model the trade-offs.
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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