The one thing to get right
"LCOA-type" describes a category, not a specification. It tells you the product is a coated aluminum entry sheet. It does not tell you the thickness tolerance, the coating chemistry or the CPK your board actually needs. Qualify the category and the specification — never the part number.
What an LCOA-type product is
LCOA / L.C.O is a brand associated with the coated aluminum entry category. The category itself is straightforward: a thin aluminum sheet — typically 1100 H18 commercial-pure aluminum in the 0.15–0.20 mm range — carried on top of the drilling stack, with a resin lubricant film applied to the drilling face.
That film is the whole point of the category. It does three jobs at once at the moment the bit first touches the stack: it cools the tip, it lubricates the flute so chips evacuate cleanly, and it limits resin smear where the bit passes through the laminate. On plain aluminum those three jobs fall to the aluminum alone. This is the mechanism behind every product in the category, whatever the brand; the differences are in how well each one executes it, which is what the comparison below is for. The category is described in more depth on what a coated aluminum entry board is.
What to compare when qualifying one
Four things decide whether a coated entry performs like the one on your drawing — and none of them is a part number.
| What to check | The question it answers | YUESHAN coated entry |
|---|---|---|
| Aluminum base | Does the base self-centre the bit and hold its thickness tolerance? | 1100 H18 commercial-pure aluminum, 0.15–0.20 mm, low softening point for bit self-centring |
| Coating chemistry | Which film matches your hole size and laminate — a thermoset or a water-soluble resin? | Both chemistries offered: thermoset film rated 220 °C, and a water-soluble resin film |
| Coating temperature rating | Does the film survive the thermal load inside your micro-via? | Thermoset film rated 220 °C for the hotter HDI and high-Tg stacks |
| Measurable outputs | Does it hold position, burr and tool life at your smallest hole? | Published benefit: cools the tip, cuts resin smear and extends micro-drill life by about 35% on HDI and RF boards |
| Back-drill variant | Is the same category needed for controlled-depth work? | One-piece coated aluminum for back-drilling, in back-drill aluminum |
Only YUESHAN specifications are given. No LCOA figure, part number or data sheet is reproduced — the comparison is made on the category and on our published values.
The coating-chemistry question is the one buyers most often skip. Thermoset and water-soluble films are not interchangeable: one is chosen for hotter stacks, the other for different handling and residue properties. We set out the trade-off in thermoset vs water-soluble coated aluminum.
When a coated entry is the right category
The category earns its cost only when the entry side is what is limiting you. It is the right answer when:
- You are snapping micro-drills on HDI work and the bit, not the backup board, is the recurring cost.
- You are fighting resin smear or a rough hole wall on RF and high-Tg laminates.
- You need hole-position accuracy below about 0.15 mm and the plain aluminum entry has stopped holding it.
- You are running controlled-depth (back-drill) work where the entry layer is part of the Z-reference.
Conversely, on standard 2–12 layer FR-4 at larger holes, a plain 1100 H18 entry is usually sufficient, and the coating is spend on a problem you do not have. The category boundary is set out in the entry board material comparison. The lubricant & coated aluminum pages carry the family in full.
The YUESHAN family in the same place
YUESHAN supplies the coated entry category from two directions, so a switch does not force a change of base material:
- Aluminum entry boards — the plain 1100 H18 baseline, for the jobs that do not need a coating.
- Lubricant & coated aluminum — the coated family, thermoset and water-soluble, for HDI, BGA, IC substrate and high-Tg work.
- Back-drill aluminum — the one-piece coated sheet for controlled-depth and back-drill stacks.
Sample quantities travel as production stock cut from our own line, with TDS and SDS attached; the qualification route is set out in how a drilling-material supplier is qualified. For the whole range against a category, start at the alternatives index.
Trademarks and scope
LCOA and L.C.O are trademarks of their respective owner. They are used on this page only to describe the coated aluminum entry category a buyer may already be specifying, within a comparison ("alternative" / "vs" / "benchmark") context. YUESHAN is not affiliated with, endorsed by or a distributor of LCOA, and no LCOA specification, part number or data sheet is reproduced on this site. See also our Terms of Use and the note on how we compare to L.C.O.
Questions buyers ask
What is an LCOA-type coated entry material?
It is a coated aluminum entry sheet — a thin aluminum base with a resin lubricant film on the drilling face, sitting in the entry position on top of the copper. It belongs to the same category as every coated and lubricated aluminum entry board; LCOA / L.C.O is one brand associated with the category, not a category of its own.
What should I compare when qualifying a coated entry alternative?
Four things: the aluminum base (alloy, temper and thickness tolerance), the coating chemistry (thermoset or water-soluble) against your hole size and laminate, the coating's rated temperature against your thermal load, and the measurable outputs — hole-position CPK, exit burr, wall roughness and micro-drill life.
When is a coated entry the right category at all?
When the entry side, not the backup side, is limiting you — micro-drill breakage on HDI, resin smear on RF and high-Tg laminates, or hole-position accuracy below about 0.15 mm. For standard 2 to 12 layer FR-4 at larger holes, a plain 1100 H18 aluminum entry is usually enough.
Is YUESHAN affiliated with LCOA?
No. LCOA and L.C.O are trademarks of their respective owner and are used here only to describe the coated aluminum entry category in a comparison context. YUESHAN is not affiliated with, endorsed by or a distributor of LCOA, and no LCOA specification is reproduced on this site.