Featured Snippet: Rule: HDI / IC / high burr -> UV melamine 880; thick or hard stack (>3.0 mm) -> UV melamine 950; cost-sensitive FR4 -> HDF
Free PCB melamine backup grade selector. Choose UV melamine 880 vs 950 vs HDF from material, hole size, stack and burr priority, with TDS densities.
Suitable for:
Answer and get a grade recommendation.
| Recommended grade | -- |
| Why | -- |
| Density / hardness | -- |
Starting-point recommendation from YUESHAN TDS; qualify on your stack and plating needs.
Within the melamine backup board family, grade decides burr control, rigidity and cost. UV melamine 880 (density 950卤30 kg/m3, hardness 80卤5HD) is the high-burr-control default; UV melamine 950 (density 980卤30 kg/m3, 80卤5HD) is the flagship grade for thick or hard stacks; HDF (density 880卤30 kg/m3, 70卤2HD) is the cost-optimal rigid support for standard FR4. This selector recommends a grade from your parameters.
Rule of thumb: high burr control / HDI → UV melamine 880; thick / hard stacks → UV melamine 950; cost-sensitive FR4 → HDF. Pair with an aluminum entry board - see the 2026 backup board comparison.
| 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.
Backup grade (hole-rich HDI)
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 UV melamine 880? A melamine backup board (density 950 kg/m3, 80HD) giving the best burr control and tool-life support for fine stacks.
What is UV melamine 950? The flagship melamine grade (density 980 kg/m3, 80HD) for thick or hard stacks needing maximum rigidity.
What is HDF backup board? A high-density fibre board (density 880 kg/m3, 70HD) giving cost-optimal rigid support for standard FR4.
Which grade for HDI? UV melamine 880 - highest burr control for hole-rich HDI / IC stacks.
Which grade for thick stacks? UV melamine 950 - rigid support above ~3.0 mm stack thickness.
Which grade for cost-sensitive FR4? HDF - balanced cost and rigid support.
What is burr control? Limiting exit burr via correct backup grade and feed.
What is nail heading? A mushroomed exit burr from poor support; the right grade prevents it.
What is drill breakage? Sudden bit snap on breakthrough; a rigid grade protects the bit.
What is hole wall roughness? Inside-hole roughness; good support keeps exits clean and platable.
What is resin smear? Melted dielectric on the hole wall from heat; good support and desmear manage it.
How do I choose backup thickness? Match to stack and hole size; thicker boards suit larger holes and harder materials.
What is the density / hardness difference? 950/980 kg/m3 at 80HD (melamine) vs 880 kg/m3 at 70HD (HDF) - the HDF is lighter and slightly softer.
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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