A PCB entry board is a thin sheet placed on top of the drilling stack. It guides the drill bit at first contact, prevents top-side burr, and ensures every hole starts at the correct location. The industry standard is 1100 H18 aluminum alloy in 0.15–0.20 mm thickness.
A PCB entry board (also called an entry sheet or entry material) is a consumable sheet placed on top of the copper-clad panel stack before drilling. Its primary function is to give the drill bit a clean, flat surface at the moment of first contact — reducing bit wander, preventing top-side burr, and ensuring the hole starts at the programmed location.
The entry board performs four specific functions:
Without an entry board — or with the wrong alloy or thickness — the bit meets the copper directly, causing wander that propagates through the stack and shows up as off-centre holes and inconsistent exit burr on the bottom.
Hole location accuracy is the most tightly toleranced dimension in PCB drilling. A drill bit that wanders by even 0.02 mm at entry can cause land violations on dense BGA and HDI designs. The entry board is the first and most important defence against this wander.
The key property is the entry board's softening temperature. 1100 H18 aluminum has a low softening point — the friction heat from the drill softens the aluminium locally, letting the bit self-centre rather than deflecting. This is why 1100 H18 (commercially pure, full-hard) became the industry standard: it combines surface rigidity for clean entry with low-temperature softening for self-centring.
There are three main types, selected based on the smallest hole size and layer count:
The standard choice for the majority of PCB drilling. 1100 H18 is commercially pure aluminium (≥99.0%) in full-hard temper. Available in 0.15 mm, 0.18 mm and 0.20 mm thickness. Best for 2–24 layer standard multilayer and through-hole boards.
Full aluminum entry specifications →
A resin-coated aluminium base where the film provides additional lubrication and cooling for microvia drilling. The thermoset film stays stable up to 220°C, preventing melt rings on hole walls. Used for HDI, BGA and IC-substrate boards with holes below Ø0.15 mm.
Full lubricant aluminum specifications →
A lower-cost coated option for general HDI drilling above Ø0.10 mm. The film dissolves in post-drill cleaning. Humidity-sensitive — not recommended for tropical climates.
Match entry board thickness to your smallest drill diameter:
See the Aluminum Entry Boards overview for the full thickness comparison table and pairing recommendations.
The entry board is the top half of the consumable stack. It works in partnership with:
A PCB entry board is a thin sheet placed on top of the drilling stack. It guides the drill bit at first contact, prevents top-side burr, and improves hole location accuracy. The industry standard is 1100 H18 aluminum in 0.15–0.20 mm thickness.
0.18 mm covers most standard drilling. Use 0.15 mm for smaller holes and 0.20 mm for larger drills or thicker stacks.
Plain 1100 H18 aluminum is the standard for most drilling. Coated entry boards have a resin lubricant film for microvia precision. Coated boards are specified where hole size is below Ø0.15 mm.
No. Entry boards are single-use consumables. Reusing an entry board risks drill wander, location error and debris contamination.
Not sure which entry board thickness or type fits your production? Send your smallest drill diameter and layer count — our engineers will recommend the grade match within one business day and ship samples within 5–7 days. Reach Mr. Lucky Xu on WhatsApp or email.
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