Backup Board Material Comparison

The one thing to get right

Compare classes on the axis that is actually limiting you. If your constraint is exit burr at a dense pattern, a denser core in the same family may change little while a harder face changes a lot. If your constraint is cost per panel on standard 4-layer work, the premium classes are spending money on a problem you do not have.

What actually changes between the classes

Strip away the grade names and the classes differ along three axes. Everything else — sheet format, cut-to-size supply, packaging — is common across the range.

• Surface hardness and flatness. This is what decides how well the exit edge is supported and how evenly the stack closes. A denser core with a fused surface resists indentation where the bit breaks through; a standard fibre surface is softer and more forgiving on bit wear.
• Surface behaviour under heat. At the break-out the bit is hottest and the material is least able to absorb it. A sealed or coated face changes how the surface responds — whether resin smears, whether debris clears as chip, and how the wall reads after the cut.
• Cost tier and process dependency. Moving from a fibre core to a laminated or coated surface raises unit cost and can add a dependency on a coating or lamination line, which is a supply-planning consideration as much as a cost one.

What does not change is the mechanism. Every class here works the same way: it supports the exit side of the hole. That is why the comparison is a question of degree and cost rather than of one material being right and another wrong. The HDF core board page covers the fibre end of the range, and the UV-cured melamine profile covers the coated end.

Scenario matrix: stack, hole and heat

Read the matrix from your constraint inwards. Each row is a working situation, not a grade recommendation — the grade inside the class still has to be pinned down.

Situation	Class to start from	Why it fits	The cost you accept
2–8 layer, smallest hole from about 0.30 mm, cost-led	HDF 840 density class	Standard exit support is enough at this diameter; density and flatness govern the result	Lowest cost tier, but support consistency varies more lot to lot — check flatness and internal bond at goods-in
4–12 layer, smallest hole around 0.20–0.30 mm	HDF 880 density class	The balanced standard: stable support without paying for surface treatment	Few — this is the class where the default answer is usually correct
Up to 12 layer with dense patterns, or where extra rigidity is wanted	HDF 950 density class	Higher-density support reduces compression under the panel and holds stack height	Higher unit cost inside the same family; the exit surface is still a fibre surface
FPC, rigid-flex or multilayer where exit burr and wall quality lead	Melamine laminate	A hot-pressed melamine face gives a hard, sealed exit interface over a resilient core	Mid tier; a harder face means more resistance at the break-out, so watch bit life
Same as above, where a light face is wanted for identification and surface checks	White melamine laminate	Same drilling mechanism as the standard face; the white face is an appearance and handling choice	Mid tier, with a face that must be named explicitly on the drawing
HDI, 6–24 layer, humid plant, or back-drilled stacks	UV-cured melamine	A crosslinked UV-cured surface seals the face, limiting moisture ingress and surface smear	Upper-mid tier; adds a coating-line dependency to supply planning
IC substrate and precision work below about 0.10 mm	Phenolic PHE	Laminated phenolic resin gives the hardest, most dimensionally stable class and the highest decomposition temperature	Premium tier, and sheet sizes and minimum quantities are less flexible than the fibre classes

Bands, not prices. The tiers above describe relative position in the range; the absolute cost of a board depends on format, thickness and quantity, and it changes — which is exactly why the comparison should be run on cost per good panel rather than on unit price.

Board price against drilling yield

The number that matters is not what a sheet costs. It is what the layer costs you per good panel, and that has three parts:

• Boards consumed. Board price divided by the number of boards a stack run consumes, per panel produced. A thicker or larger-format sheet that yields more boards per panel can be cheaper per panel than a cheaper sheet that yields fewer.
• The defect share it removes. Every defect class that reaches the exit side carries a scrap or rework cost. A harder or better-sealed surface earns its premium only against the defect share it actually reduces on your line.
• The effect on bit life. Bit cost divided by hits per bit. A surface that raises wear per hit shortens bit life, and that belongs on the same side of the ledger as the board price.

Written out, the comparison is: (board price ÷ boards per panel) + (defect share × panel value) + (bit cost ÷ hits per bit) per good panel. Two classes that are a tier apart on price are often much closer on this number than the price list suggests, and occasionally the premium class wins — but only where the constraint it relieves is the one that is actually costing you panels. The drill cost calculator and the cost-per-panel calculator put your own numbers into that expression.

Price comparisons often stop at mechanical vs laser drilling, but the two cost curves bend differently. Mechanical drilling cost per hole falls as hit count rises and board amortization spreads over more panels; laser via cost is dominated by capital and cycle time, and only becomes economical at microvia densities mechanical tools cannot reach. For the panel sizes this page compares, board price against drilling yield stays the controllable lever.

Where each class stops working

Each class has a regime where it is the right answer and a boundary beyond which it stops being one. Knowing the boundary is more useful than a ranking, because the boundary is what makes you re-qualify instead of assuming.

Class	Published parameters that set the boundary	Boundary you should respect
HDF (840 / 880 / 950)	840 / 880 / 950 kg/m³ density classes, 70 HD class hardness, flatness ≤0.10 mm, typical thickness 2.0 / 2.5 mm	Below roughly 0.20 mm the entry side and the stack dominate the result — re-qualify rather than assume
White melamine laminate	2.5 ±0.15 mm thickness, density ≥980 kg/m³, surface hardness 83 ±5 HD, warpage ≤0.6%, moisture ≤9%	Hole capability is stated from 0.20 mm; the face is an appearance choice that must be named on the order
UV-cured melamine	880 kg/m³ density class, hardness 80 ±3 HD, thickness 2.0 / 2.5 mm, sealed surface	Where the coating line is the supply constraint, plan formats ahead rather than assuming instant substitution
Phenolic PHE	Laminated phenolic resin, 90 ±5 HD, thickness 1.50 mm, decomposition temperature above 220 °C, flatness ≤0.10 mm, exit burr ≤0.05 mm	Sheet sizes start from a smaller set; confirm the format and minimum quantity before specifying it into a running program

The pattern in that table is worth stating plainly: the fibre classes are limited by surface, the laminated and coated classes are limited by cost and supply flexibility, and the phenolic class is limited by format and quantity rather than by performance. The phenolic PHE board profile and the melamine laminate profile carry the full parameter sets. Where moisture rather than hardness is your limiting factor, the moisture control guide is the more useful read than any of these comparisons.

The full range at a glance

This page compares the classes on cost-per-panel behaviour. For a single index of every family YUESHAN supplies — including the two that sit beside the five classes rather than inside them — see the backup board materials hub. The two additions are the lubricated composite (aimed at heat rather than hardness) and the 2.7 mm coated wood board (the exit-support step up once the 2.0 / 2.5 mm grades run out of body); the kraft paper base is the fibre base behind the phenolic class and the press packing used in lamination cycles.

Family	Base / build	Where it fits	Profile
HDF 840 / 880 / 950	High-density fibre board, three density classes	2–12 layer cost-first default; 950 where extra rigidity is wanted	HDF core board
Melamine laminate	HDF core + hot-pressed melamine face	FPC, rigid-flex and multilayer where exit burr and wall quality lead	Melamine laminate
White melamine laminate	Same build, light face	Identification and surface-check jobs; a named drawing item	White melamine board
UV-cured melamine	HDF core + UV-crosslinked sealed face (840 / 880 / 950)	HDI, 6–24 layer, humid plants and back-drilled stacks	UV-cured melamine
Lubricated composite	Three-layer build: HDF core + lubricant resin layer + reinforcing resin layer	Heat-limited stacks where drill temperature and wear, not hardness, are the constraint	Lubricated composite board
2.7 mm coated wood	Dense fibreboard at 2.7 mm, UV-coated or melamine-faced	The step up when 2.0 / 2.5 mm grades run out of body on thick stacks	2.7 mm coated wood
Phenolic PHE	Laminated phenolic resin	IC substrate and precision work below about 0.10 mm	Phenolic PHE board
Kraft paper base	High-temp virgin fibre base	Base behind the phenolic class; press packing in lamination cycles	Kraft paper base

The five classes above the lubricated and wood-board additions are the ones this page ranks on cost per good panel. Buying by a named brand instead — an LCOA-type coated entry, an LE SHEET-type lubricated entry, an Alltech-type range — is a separate decision about the entry side, covered in the brand-alternative comparisons.

Running the comparison on your line

Nothing in the table above survives contact with a specific plant unchanged, because the ranking depends on the bit, the parameters and the panel build you run. Four steps make the trial worth the time:

• Hold everything but the class. Same bit and hit count, same parameters, same panel lot, same stack position. If two variables move, the result is not attributable.
• Measure the four outputs that matter. Hole-position CPK, maximum deviation, hole-wall roughness and exit burr — read as a set, not one at a time. A single metric cannot rank two boards.
• Score on cost per good panel. Convert the result through the expression above before declaring a winner. A class that improves burr but shortens bit life by more than the burr costs has not won.
• Re-run at the smallest hole. The class that holds at 0.25 mm is not automatically the class that holds at 0.10 mm, because the controlling mechanism changes with diameter.

If you would rather narrow the class before spending machine time, send the smallest hole, the stack and the layer count and let us make the first cut — the engineering desk answers that with a class recommendation and the grade inside it, and the melamine grade selector does the same job inside the melamine family.

Questions buyers ask