Featured Snippet: Rule: hole <=0.15mm or HDI/IC -> Lubricant aluminum; back-drilling -> Back-drill coated; else -> Plain aluminum entry sheet
Free PCB entry board selector. Pick the right entry board (plain aluminum, lubricant or back-drill coated) from material, hole size and layers.
Suitable for:
Answer and get a recommendation.
| Recommended entry board | -- |
| Why | -- |
Recommendation is a starting point - match to your stack and qualify on a sample panel.
The entry board sits on top of the stack and decides how the bit enters: it centres the drill, cools the tip and cuts drill wander. Choosing wrong means burrs, broken micro drills and poor drill registration. This selector recommends a board type from your material, hole size and layer count.
Match with a quality backup board - see our backup board range and the aluminum vs phenolic entry guide.
| 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.
Drill wander (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 an entry board? An entry board sits on top of the stack to centre and cool the drill bit on entry.
What is aluminum entry sheet? A plain aluminum sheet used as entry board for standard PCB holes.
What is lubricant aluminum? An entry sheet with a self-lubricating coating that cools and centres the bit on micro-holes.
What is back-drill coated aluminum? A coated entry sheet for controlled-depth back-drilling, holding stub accuracy.
Why use an entry board? It cuts drill wander, cools the tip and improves hole quality versus drilling bare stack.
What is drill wander? Lateral bit deflection on entry; a good entry board minimises it for tight registration.
What is drill registration? Hole position accuracy versus datums; entry support keeps it tight.
When do I need lubricant aluminum? For holes <=0.15 mm, HDI/IC substrates, or heat-sensitive materials.
What is the difference between plain and coated entry? Coated/lubricant grades add cooling and centring for micro-holes; plain is cheaper for standard holes.
What is back-drilling? A second controlled-depth pass removing unused via stub to protect signal integrity.
What is stub? The unused via barrel left after lamination; back-drilling removes it.
What is signal integrity? Clean high-frequency transmission; stubs and rough holes degrade it above ~1 GHz.
What is a backup board? The board under the stack supporting exit and controlling burr.
What is burr control? Limiting exit burr via correct feed and board support.
What is nail heading? A mushroomed exit burr from poor support or wrong feed.
What is drill breakage? Sudden bit snap, often from heat or poor entry support on micro-holes.
How do I choose entry thickness? Match to diameter and stack; thicker sheets suit larger holes, thinner for micro-vias.
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.
Product Page →← Tools Hub Request TDS & Free Sample →