Featured Snippet: Chip Load (mm/tooth) = Feed Rate (mm/min) / (RPM x Flutes)
Free PCB chip load calculator. Get chip load (mm/tooth) from feed rate, spindle RPM and flutes, plus surface speed and board suggestion.
Suitable for:
Enter feed rate, RPM, flutes and drill diameter.
| Chip load | -- mm/tooth |
| Surface speed (Vc) | -- m/min |
| Suggested entry board | -- |
| Suggested backup board | -- |
| Burr risk | -- |
Typical PCB micro-drill chip load: 0.005-0.020 mm/tooth. Compare your number to the range table below.
Chip load is the material each flute removes per revolution (mm/tooth). It couples spindle RPM to feed rate and sets heat, burr and hole wall roughness. When you only know your feed and speed, this tool reverses the formula to recover chip load, shows surface speed and suggests entry/backup boards so you can confirm the setting is in band before a production run.
| Drill diameter | Chip load (mm/tooth) | Feed (m/min) @ ~90k RPM, 2 flutes |
|---|---|---|
| 0.10 mm | 0.005-0.010 | 0.9-1.8 |
| 0.20 mm | 0.008-0.015 | 1.4-2.7 |
| 0.30 mm | 0.010-0.020 | 1.8-3.6 |
| 0.50 mm | 0.015-0.030 | 2.7-5.4 |
| 0.80 mm | 0.020-0.035 | 3.6-6.3 |
Chip load above ~0.020 mm/tooth on a 0.20 mm drill usually raises burr and drill breakage risk; below the band the bit rubs and overheats, cutting tool life. The entry board and backup board you pair with the setting decide how much margin you have.
| 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.
Chip load (0.20 mm drill, FR4)
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 chip load in PCB drilling? Chip load is the material each flute removes per revolution (mm/tooth). It links RPM to feed rate and controls heat, burr and hole-wall quality.
How do I calculate chip load? Chip load = Feed rate (mm/min) divided by (RPM x flutes). This calculator reverses the feed formula for you.
What is a good chip load for a 0.20 mm drill? About 0.008-0.015 mm/tooth; thinner bits need less, larger drills tolerate more. Validate on your stack.
What is feed rate? Feed rate is how fast the bit plunges (mm/min) = RPM x chip load x flutes.
What is surface speed (Vc)? Vc is the linear cutting-edge speed (m/min) = pi x diameter x RPM / 1000.
Why does chip load matter for burr? Too-high chip load overloads the edge and tears the exit; too low makes the bit rub. Both raise burr.
How does chip load affect tool life? A chip load in band keeps the edge cutting instead of rubbing, extending hits per bit.
What is drill breakage? Sudden bit snap, often from wrong feed/chip load or poor support on micro-holes.
What is hole wall roughness? Inside-hole roughness; off-band chip load worsens it and hurts plating.
How do I lower chip load? Raise RPM or lower feed; keep the bit in its stable cutting band for the diameter.
What entry board pairs with tight chip load? A lubricant aluminum entry sheet cools and centres micro-holes so you can hold a low chip load.
What backup board should I use? UV melamine 880 for HDI/clean exits, HDF for cost FR4, UV melamine 950 for thick/hard stacks, phenolic for Rogers/PTFE/ceramic.
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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