A multilayer (6-24 layer) PCB drilling guide matches backup board and entry sheet to the stack, from cost-sensitive consumer boards to automotive and telecom. Key variables are smallest hole size, layer count, stack height and humidity. Pick HDF for cost, UV melamine for burr control, coated entry for microvia quality.
Multilayer boards (6-24 layers) span a wide range — from cost-sensitive consumer electronics to high-reliability automotive and telecom boards. The key variables that determine your material choice:
| Factor | Impact on Material Selection |
|---|---|
| Layer count | More layers = thicker stack = more drill friction = need higher hardness backup |
| Copper thickness | >3 oz thick copper requires phenolic-grade hardness (90 HD) |
| Via diameter | Standard vias (≥Ø0.25 mm) vs. small vias (Ø0.15-0.25 mm) have different entry sheet needs |
| Tg rating | High-Tg materials (>170°C) need heat-resistant coated entry sheets |
| Application | Automotive/telecom demand higher reliability than consumer electronics |
| Environment | High-humidity regions benefit from UV-coated backup boards |
Best for: Consumer electronics, industrial controls, LED lighting boards
| Layer | Product | Why |
|---|---|---|
| Entry sheet | Aluminum Entry 1100 H18 (0.18 mm) | Full-hard temper provides rigidity; ±0.005 mm thickness tolerance for burr-free drilling |
| Backup board | HDF 880 (75±2 HD, 880 kg/m³) | Cost-effective; meets IPC Level 2 for standard multilayer; ≤0.10 mm flatness |
Cost profile: Lowest material cost per panel. Ideal for high-volume, price-sensitive production.
Best for: Telecom equipment, servers, industrial automation, mid-range automotive
| Layer | Product | Why |
|---|---|---|
| Entry sheet | Aluminum Entry 1100 H18 or Coated Aluminum | Standard aluminum sufficient for ≥Ø0.20 mm; upgrade to coated for smaller vias |
| Backup board | UV Melamine 840 (80±5 HD) or HDF 880 | UV coating provides moisture resistance for humid environments; smoother surface reduces burrs |
Cost profile: Moderate upgrade (~15-20% over Tier 1) with significant quality improvement for smaller vias.
Best for: Automotive (safety-critical), 5G telecom backplanes, aerospace, medical
| Layer | Product | Why |
|---|---|---|
| Entry sheet | Coated Aluminum (thermoset-coated) | Lubrication reduces drill wear on thick copper; heat resistance for high-Tg materials |
| Backup board | UV Melamine 950 (83±3 HD, 980 kg/m³) or Phenolic PHE (90±5 HD) | Maximum rigidity for thick stacks; UV coating for clean chip evacuation |
Cost profile: Higher material cost, but reduces total cost of ownership through fewer drill breaks, higher stack heights and lower scrap rates.
Thick copper generates significantly more friction heat during drilling. Standard HDF (70 HD) compresses and degrades under thick-copper drilling loads.
Required upgrade:
In environments with >60% relative humidity (common in India, Southeast Asia and Bangladesh), standard HDF boards absorb moisture and warp — causing flatness deviations that lead to drill breakage.
Recommended stack:
Many multilayer manufacturers use traditional melamine backup boards (80±3 HD) for micro-drilling. YUESHAN's UV Melamine 950 offers equivalent hardness (83±3 HD) and density (980 kg/m³) at approximately 22% cost savings.
| Parameter | Traditional Melamine | UV Melamine 950 |
|---|---|---|
| Hardness | 80±3 HD | 80±5 HD |
| Density | 980±30 kg/m³ | 980±30 kg/m³ |
| Thickness | 2.50±0.15 mm | 2.50±0.15 mm |
| Surface | Smooth | UV-cured smooth |
| Relative cost | Baseline | ~22% lower |
Recommendation: If you are currently using traditional melamine backup boards, test UV950. Same performance, lower cost.
| Backup Board | Max Stack (6-12 L) | Max Stack (12-24 L) |
|---|---|---|
| HDF 880 (70 HD) | 3 panels | 2 panels |
| UV Melamine 840 (75 HD) | 3 panels | 3 panels |
| UV Melamine 880/950 (80 HD) | 4 panels | 3-4 panels |
| Phenolic PHE (90 HD) | 4 panels | 4 panels |
Higher stack height = more panels per drill cycle = higher throughput. The productivity gain often offsets the higher per-panel material cost.
Before placing an order, confirm:
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