Featured Snippet: Thermal Index = clamp( (RPM/1000 x feed x materialAbrasion x dia) / coolingFactor , 1, 10 )
Free PCB drill thermal load calculator. Estimate relative tip heat from RPM, feed, diameter and material, and read a cooling/board recommendation.
Suitable for:
Estimate relative tip heat (1 = cool, 10 = hot).
| Thermal index | -- / 10 |
| Recommendation | -- |
Relative heat index - confirm with real temperature / hit-count data.
Drilling generates heat at the tip; too much softens the edge, smears resin and shortens tool life. Heat scales with RPM, feed and material abrasiveness, and is pulled away by a good entry board. This tool returns a relative thermal index and a cooling/board recommendation for stacks like Rogers, PTFE, ceramic and IMS.
Heat-sensitive stacks - Rogers, PTFE, ceramic, IMS/copper-core - need lower surface speed and strong cooling. A lubricant aluminum entry sheet pulls heat from the tip, and a phenolic backup board supports the exit without adding thermal mass. Keep feed in the stable band to protect tool life and avoid resin smear.
| Material | Density (kg/m³) | Surface Hardness (HD) | Best For |
|---|---|---|---|
| UV Melamine 950 | 980 ± 30 | 80 ± 5 | IC Substrate, HDI micro-via |
| UV Melamine 880 | 950 ± 30 | 80 ± 5 | HDI, high-layer-count FR4 |
| HDF 880 | 880 ± 30 | 70 ± 2 | Standard FR4 multilayer |
| Phenolic (standard) | 750 ± 40 | 55 ± 5 | Back-drilling, rigid-flex |
| Aluminum entry sheet | N/A (metal foil) | N/A | Universal entry protection |
| Lubricated aluminum (LE) | N/A (coated foil) | N/A | Micro-via, HDI, high-Tg |
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.
Tip heat (Rogers stack)
Representative field benchmarks for a 0.20 mm drill on Rogers high-frequency laminate; actual results vary with stackup, machine and consumables — validate on your own panels.
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What is drill tip heat? Heat generated at the cutting edge during drilling; excess softens the bit and smears resin.
What raises tip heat? High RPM, high feed, small diameter, abrasive or heat-sensitive material.
What is resin smear? Melted dielectric on the hole wall from excess heat; desmear manages it.
How do I cool the bit? Lower feed/RPM into band, add a lubricant entry sheet, ensure chip evacuation.
What is a lubricant entry sheet? Self-lubricating entry that cools and centres the bit on micro-holes.
What is tool life? Total holes per bit; heat shortens it through edge dulling.
Why are Rogers/PTFE heat-sensitive? They soften or flow under heat, needing lower surface speed.
What is surface speed (Vc)? Linear edge speed = pi x diameter x RPM / 1000; the real heat knob.
What backup board for heat-sensitive? Phenolic gives support without adding thermal mass on Rogers/PTFE/ceramic.
What is drill wander? Lateral deflection on entry; cooling support reduces it.
What is chip evacuation? Removing swarf; poor evacuation traps heat and accelerates wear.
What is via reliability? Long-term via integrity; controlled heat and clean holes support it.
Standard aluminum 1100 H18 entry foil (0.15–0.20 mm) is the universal choice for FR4 and back-drilling. Lubricated aluminum entry sheets (LE/CAE) add a thermoset coating that phase-change cools the drill tip by 15–22%, reducing resin smear and drill breakage on HDI and micro-via work. Water-soluble coated entry boards offer an alternative for rigid-flex where residue cleanliness is critical.
UV melamine 950 (980 kg/m³, 80±5 HD) is the premium choice for IC substrate and HDI where exit burr must be near zero. UV melamine 880 (950 kg/m³) suits high-layer-count FR4. HDF 880 (880 kg/m³, 70±2 HD) balances cost and performance for standard multilayer. Phenolic boards are preferred for back-drilling and rigid-flex due to their machinability.
1100 H18 (99% Al) is the industry standard for entry foil. 3003 and 5052 alloys offer higher strength for thicker entry boards but may increase drill wear. The choice of alloy affects chip load stability and burr formation on the entry side.
Kyocera Precision Tools — PCB drilling ↗
Thermoset-coated (LE/CAE) entry boards provide lubrication through phase-change cooling at 120–180°C. Water-soluble coated boards dissolve in cleaning. Uncoated aluminum relies purely on mechanical centering. The coating choice directly affects drill temperature, chip evacuation, and hit count.
YUESHAN — LE Sheet drill temperature data
Drill tip temperature can exceed 300°C on standard FR4 without proper consumables. The entry board absorbs 20–30% of frictional heat; the backup board dissipates exit heat. Lubricated entry systems reduce peak temperatures by up to 30%, directly reducing resin smear and hole wall roughness.
Rogers Corp — RO4000 laminates ↗
Micro-drill breakage is most often caused by chip clogging in the flute, not by mechanical overload. Lubricated entry boards eliminate the chip adhesion failure mode. A worn entry board (excessive hits per sheet) increases drill wander risk — replace entry sheets at the same interval as drill change.
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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