Background
An Indian PCB manufacturer based in Bangalore and Maharashtra, producing multilayer and HDI boards for automotive, telecommunications and industrial applications, faced a critical bottleneck. As India's PCB market grew rapidly — driven by the government's ECMS (Electronics Component Manufacturing Scheme) initiative — the company was scaling up its HDI production capacity but struggling with inconsistent drilling material quality.
Before engaging YUESHAN, the manufacturer sourced backup boards and entry sheets from multiple local and Chinese suppliers. The variation between batches was causing unpredictable yield loss on their HDI line.
The Challenge
Three recurring issues plagued their drilling process:
- Inconsistent backup board flatness — Flatness deviations exceeded 0.15 mm, causing drill bit breakage on 12+ layer HDI boards with Ø0.15 mm vias.
- Moisture-related warpage — Bangalore's humid climate (often >65% RH) caused standard HDF boards to absorb moisture and warp between delivery and use, leading to stack alignment problems.
- Aluminum entry sheet contamination — Surface oils from previous suppliers left residue on panels, requiring additional cleaning before drilling.
The Solution
After evaluating five suppliers, the manufacturer standardized on a YUESHAN material stack:
| Layer | Product | Specification | Role |
|---|---|---|---|
| Entry sheet | Aluminum Entry 1100 H18 | 0.18 mm, ±0.005 mm tolerance, oil-free surface | Burr-free drilling, no panel contamination |
| Backup (standard lines) | HDF 880 | 880±30 kg/m³, 75±2 HD, ≤0.10 mm flatness | Cost-effective for 6–12 layer boards |
| Backup (HDI lines) | UV Melamine 880 | 950±30 kg/m³, 80±3 HD, UV-cured surface | Moisture-resistant, smooth surface for micro-via drilling |
Why they chose YUESHAN:
- Flatness guarantee: Every shipment verified ≤0.10 mm flatness — a spec previous suppliers could not consistently meet
- Moisture adaptation: The UV-cured surface on the melamine backup board acts as a moisture sealant, preventing the warpage that plagued standard HDF in humid conditions
- Surface cleanliness: Aluminum entry sheets supplied with guaranteed oil-free surface, eliminating the contamination issue entirely
- Full product line: One supplier for both standard and HDI lines simplified procurement and quality management
The Result
| Metric | Before YUESHAN | After YUESHAN | Improvement |
|---|---|---|---|
| Drill breakage rate (HDI line) | 2.3% | 0.8% | −65% |
| Backup board scrap (warpage) | 4–5% | <1% | −80% |
| Stack height (HDI) | 2 panels | 3 panels | +50% throughput |
| Cleaning time per shift | 45 min | 15 min | −67% |
Over three years the partnership deepened from an initial 3,500-piece HDF order to regular LCL shipments covering the full material stack. The manufacturer specifically noted consistent quality across every shipment — no batch-to-batch variation — and responsive communication with sample requests fulfilled within 5–7 working days.
Why This Matters for Similar Manufacturers
This case is directly relevant to any PCB maker facing similar conditions:
- Humid climate challenges (India, Southeast Asia, Bangladesh) — A UV-coated backup board's moisture resistance is a proven differentiator, not a marketing claim. See our guide on how to choose the right backup board for more detail. For back-drill applications, Indian manufacturers can refer to our Back-Drill Aluminum Sheet India Selection Guide with local CPK data and HW600/HW900 grade recommendations.
- Transition from standard multilayer to HDI — Upgrading from HDF to UV Melamine allows higher stack heights without quality compromise. Read more in our HDI & IC Substrate solution page.
- Multiple supplier complexity — Consolidating to one supplier for the full material stack reduces procurement overhead and quality variability.
Your Next Step
If you are facing similar drilling quality challenges, send us your current backup board and entry sheet specs, your PCB type (layer count, via diameter, copper thickness), and your current scrap rate. We will provide a side-by-side comparison and a sample recommendation.