Direct answer: YUESHAN UV melamine PCB backup boards with UV-cured moisture-sealed HDF surface for 6–24 layer, HDI and back-drill lines. 840/880/950 grades, flatness ≤0.10 mm, TDS and samples. Buyers typically qualify it by density/hardness, thickness, flatness, moisture behavior, exit burr, drill wear and compatibility with the entry sheet.
Key Takeaways
- This page is the commercial view of the UV-cured grade: supplier, specification, sample, TDS/SDS and how a quotation is built.
- The Material Profile sets out what the UV cure changes at the surface, and the test data behind the flatness and hardness figures.
- Entity set owned by this page: UV melamine PCB backup board, UV coated backup board, moisture sealed HDF, melamine coating, HDI backup board, microvia backup board, back-drill backup, low smear, hole wall quality, warpage, humidity resistance, surface hardness, flatness.
UV Melamine PCB Backup Board Supplier for PCB Drilling
UV Melamine is YUESHAN's main upgrade from bare HDF when moisture stability, low smear and tighter multilayer/HDI drilling become more important. The UV-cured face is designed as a sealed, harder drilling surface while the HDF core maintains support and machinability.
Industry pages ranking around this product category consistently use procurement entities such as backup board, backing board, drilling support, density, thickness tolerance, surface hardness, warpage, standard sizes, HDF core, FPC, HDI, BGA, multilayer PCB and customized size. This page integrates those terms only where they describe a real buyer decision.
Commercial Specifications
| Specification | YUESHAN |
|---|---|
| Core | HDF |
| Surface | UV-cured melamine coating |
| Grades | UV Melamine 840 / 880 / 950 |
| Hardness | Approx. 80±5 / 80±3 / 83±3 HD by grade |
| Finished thickness | 2.0 / 2.5 mm (2.0 / 2.4 mm HDF substrate + UV facing) |
| Flatness | ≤0.10 mm |
| Application | 6–24 layer, HDI, microvia and back-drill PCB |
Standard board formats: 940 × 1245 mm (37 × 49 in), 1041 × 1245 mm (41 × 49 in) and 1092 × 1245 mm (43 × 49 in). The UV face is applied to a 2.0 / 2.4 mm HDF substrate, which gives a finished board of 2.0 / 2.5 mm. Cut sizes such as 520 × 620 mm are taken down from these standard boards, and custom size requests are quoted on the same boards to order. Confirm the current TDS before final drawing release or incoming inspection.
Grade Selection
| Grade | Key specification | Typical role |
|---|---|---|
| UV Melamine 840 | Moisture-sealed HDF surface | 6–16 layer / humid lines / FPC |
| UV Melamine 880 | 80±3 HD class, 2.0/2.5 mm | 12–24 layer, HDI and back-drill workhorse |
| UV Melamine 950 | 83±3 HD class, 2.5 mm, dense HDF core | Recommended default for tighter HDI / microvia tolerance |
Use the PCB Backup Board Selector if you want a quick starting grade from layer count, smallest drill, humidity and exit-burr target.
What the UV-Cured Face Is Built to Control
- Surface behaviour across a humid shift: the UV-cured face is sealed, so a room that starts dry and ends damp does not change how the board presents itself to the drill.
- Warpage on fine-pitch work: held to 0.6% so the exit plane stays predictable hole after hole — a tighter figure than the melamine laminate grade.
- Back-drill depth reference: a sealed and stable surface keeps the controlled-depth reference repeatable where back-drilling sets the stub length.
- Small-hole entry support: built as a composite board — firm UV-cured surface over a resilient core — for fine mechanical holes rather than large-diameter roughing.
- Storage drift: the grade is specified around controlled storage temperature and humidity, so the flatness bought at dispatch survives normal factory storage.
- Batch consistency: a 1000±50 kg/m³ core with an 80±3 Shore D face keeps successive deliveries inside the same window.
UV Melamine vs HDF vs Melamine Laminate vs Phenolic
From the UV side the deciding variables are the drilling floor and the hole size, not the layer count on its own.
| Backup type | How the surface behaves as humidity moves | Best-fit drilling window | Detail |
|---|---|---|---|
| UV Melamine | Sealed by UV cure; behaviour does not drift as relative humidity rises | 6–24 layer HDI, microvia and back-drill work in humid plants | This page |
| Melamine Laminate | Fused melamine skin; dimensionally stable but not sealed | FPC, rigid-flex and 12–24 layer precision drilling | melamine laminate build |
| HDF | Plain fibreboard; takes on and gives back moisture with the room | 2–12 layer standard production in controlled shops | plain HDF board |
| Phenolic PHE | Rigid thermoset, largely humidity-insensitive but brittle as scrap | Selected IC-substrate and precision routing work | phenolic PHE build |
Where the UV Grade Is Specified
Fine Holes on Sealed Support
Where the smallest hole in the program decides the grade, and smear rather than burr is the limiting defect.
HDI and microvia solution →Controlled-Depth Back-Drilling
The stub length a back-drill leaves behind is only as repeatable as the support plane underneath it.
Back-drill selection guide →Plants Without Climate Control
South and Southeast Asian lines where the room changes through the day and board storage is not fully sealed.
Moisture control guide →Plant & Process Evidence Behind the UV-Faced Grade
The UV grade is a two-layer product, so the evidence has to cover both layers: the HDF substrate that carries the board and the UV-cured facing that becomes the working surface.
Buyer Qualification Checklist for a UV Line
UV questions are mostly about the room, not about the board:
- typical and worst-case relative humidity and temperature on the drilling floor;
- whether boards are opened and left on the line, or kept sealed between shifts;
- layer count, laminate family and the smallest hole in the program;
- whether back-drilling is used, and the stub-length tolerance it has to hold;
- hole-wall quality target, and the desmear load it currently creates;
- required finished thickness — 2.0 mm or 2.5 mm — and any cut size;
- monthly volume and destination port.
Send the UV line conditions to Mr. Lucky Xu →
Entry-Side Pairing for HDI and Back-Drill Work
On a sealed backup board the entry side has to be as stable as the support underneath it.
Lubricant-Coated Aluminum
The default pairing for HDI and microvia work: less friction at the entry, and less heat carried down into the hole.
Lubricant aluminium sheet →AA1100 H18 Aluminum Entry Sheet
Use where the entry side only has to guide the bit in and carry it back out of the panel.
Aluminium entry board →Composite Entry Board
Resin-coated entry for controlled-depth back-drilling where the stub length, not the entry burr, is the target.
Back-drill entry board →Ordering, Lead Time & Customization
Minimum Order & Pricing Basis
Shipped on a 1 × 20GP container basis with mixed grades allowed in the same container; below a full container, EXW terms apply. UV Melamine loads 200 sheets per pallet and 24 pallets to a container. The quotation follows the coating grade and the core density band, because the UV-cured face and the resilient core are specified as a pair rather than as separate line items.
Lead Time Logic
Lead time runs 12 days from receipt of the order for a two-container booking, and starts once the coating specification and the density band are fixed. UV facing is a separate operation from board pressing, so the schedule follows the coating batch plan; trial quantities are inserted ahead of the bulk coating batch.
Customization Limits
Standard boards are 940 × 1245 mm (37 × 49 in), 1041 × 1245 mm (41 × 49 in) and 1092 × 1245 mm (43 × 49 in). The UV face is applied to a 2.0 / 2.4 mm HDF substrate, giving a finished board of 2.0 / 2.5 mm. Cut-to-size panels including 520 × 620 mm are produced from these boards to order, so a custom size is quoted on the same substrate; a finished thickness outside the published range is not offered.
Industry & Standards Reference Set
- IPC design standards
- high-precision white backup board terminology
- YUESHAN technical material profile for this product
Always qualify YUESHAN using its current TDS and sample results.
FAQ
What is UV Melamine PCB Backup Board?
It is a composite backup board with a UV-cured melamine face over a resilient HDF core, built for small-hole drilling. This page carries the commercial specification, qualification, sample and ordering detail; composition and process mechanisms are in the material library at https://www.yueshanpcb.com/materials/uv-backup-board/.
How does the UV face change the board against plain melamine?
The UV-cured face is sealed, so it does not take on moisture the way an unsealed face does, and warpage is held to 0.6%. It is applied to a 2.0 / 2.4 mm HDF substrate, giving a finished board of 2.0 / 2.5 mm.
Is it worth the extra cost if our drilling room is climate controlled?
In a genuinely stable room a melamine laminate grade usually holds the burr target at lower cost. UV pays back where humidity swings through the day, boards sit open on the line between shifts, or back-drilling has to hold a stub tolerance.
Does it suit HDI, microvia and back-drill work?
That is the intended window: 6–24 layer HDI, microvia and controlled-depth back-drilling, where hole-wall quality and a repeatable exit plane matter more than board cost.
What is the minimum order and lead time?
Export orders ship on a 1 × 20GP container basis with mixed grades allowed in one container; below a full container, EXW terms apply. Lead time runs 12 days from receipt of the order for a two-container booking, and follows the coating batch plan.