Differences Between Solid PCB and Hollowed PCB

2025-07-16

1. Physical Structure Differences

Solid Aluminum Substrate:

  • Sandwich Structure: Copper foil (conductive layer) + Dielectric layer (insulation) + Solid aluminum base

  • Thermal Conduction Path: Heat transfers vertically through the dielectric layer to the aluminum base, then spreads laterally.

Why:

  • "全铝基板" is technically termed "solid aluminum substrate" to emphasize its monolithic base.

  • "三明治结构" uses "sandwich-type laminate," a standard industry metaphor.

  • "垂直传导...平面扩散" dynamically translates as "vertical transfer... lateral spread" for engineering precision.


Hollowed Aluminum Core Board:

  • Hybrid Structure: Through-holes cut in standard FR4/CEM board, locally embedded with aluminum blocks.

  • Thermal Conduction Path: LED heat → copper foil → thermal adhesive/solder → embedded aluminum block → heatsink.

Why:

  • "镂空型" → "hollowed" conveys machining process; "core board" specifies its hybrid nature.

  • "贯穿孔" uses "through-holes," a PCB manufacturing term.

  • Thermal path verbs () create visual flow matching the original.


2. Core Performance Comparison

CharacteristicSolid Aluminum SubstrateHollowed Aluminum Core Board
Thermal Conductivity1-8 W/(m·K) (dielectric)>200 W/(m·K) (aluminum block)
Thermal Resistance≤1.0°C/W0.5-3.0°C/W (depends on TIM)
Mechanical StrengthHigh rigidityEdge cracking risk
Circuit DesignSingle-layerMulti-layer possible
Dielectric Withstanding≥3.75 kVElectrical arcing risk
CTE MatchingGood (Cu/Al ≈ Chip)Poor (FR4/Al mismatch)

Why:

  • Table headers use active terms (RigidityEdge cracking risk) for impact.

  • Units standardized: **℃/W°C/W**; kV retained internationally.

  • "热膨胀系数匹配" simplified to "CTE" (industry jargon) + "matching" for clarity.


3. Thermal Mechanism Analysis

Solid Aluminum Advantages:

Uniform Heat Dissipation: Monolithic base prevents hotspots (Fig.1).
Low Interface Resistance: Direct contact with heatsink.

Hollowed Board Defects:

Thermal Interface Trap: Adhesive/solder layers (0.2–0.5°C·cm²/W) become bottlenecks.
Heat Flux Bottleneck: Narrow aluminum blocks cause heat accumulation (Fig.2, red zone).

LED

Why:

  • "热流密度↑→温升加剧" translated as "Heat Flux Density↑ → Temperature Spike" with symbols intact.

  • Mermaid diagram labels fully localized (e.g., "面积不足""Insufficient Area").


4. Reliability Risks

Hollowed Board:

  • CTE Mismatch Cracking: FR4 (15 ppm/°C) vs. Al (23 ppm/°C) causes solder fatigue (–40°C~85°C cycling).

  • Moisture Ingress: Seams between Al/FR4 invite corrosion (e.g., 12% failure in streetlights @3yrs).

Solid Aluminum:

  • Dielectric Aging: Organic insulation degrades under prolonged heat.

Why:

  • "湿气渗透""Moisture Ingress" (engineering term).

  • Real-world data ("路灯项目3年故障率12%") contextualized for global audience.


5. Economics & Applications

FactorSolid Aluminum SubstrateHollowed Core Board
Cost (1.5mm thickness)$2-8$1-3 (50% less Al)
High-Power Scenarios (>5W/cm²)MandatoryContraindicated (>90% failure risk)
Low-Power Modules (<1W)Cost-inefficientIdeal (e.g., SMD2835 tubes)
Complex CircuitsRequires external driverIntegrated drivers in FR4 areas

Why:

  • "禁用" strengthened to "contraindicated" (medical term repurposed for technical severity).

  • "外接驱动板" ➔ "external driver" (industry-standard).


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