Key Takeaways
- Back-drill requires a dedicated entry sheet — standard entry boards can't deliver the stub control 5G/servers demand.
- One-piece + margin-reserved design beats laminated structures for stub accuracy and yield.
- IPC-6012F (Section 1.4.3) defines back-drill depth requirements — our sheets are designed to support compliance.
What Is a Back-Drill Aluminum Sheet?
A back-drill aluminum sheet is a dedicated entry material used during the second (controlled-depth) drilling pass on back-drilled PCBs. When you back-drill, the bit enters the panel a second time at a prescribed depth to remove the unused via barrel — improving signal integrity on high-speed digital, 5G and server boards.
A dedicated back-drill entry sheet performs four functions:
- Locates the bit at the second entry point with reference accuracy.
- Stabilises the drill through the controlled-depth pass.
- Lubricates to reduce heat and bit wear during the second entry.
- Maintains Z-reference so every hole in the panel meets stub-length target.
One-Piece + Margin-Reserved: Why It Matters
The one-piece construction with margin-reserved design holds depth tolerance tight so stub length control stays within CpK on every back-drill pass.
The one-piece design (aluminum base + coating as a single unit, with reserved edges) eliminates the seam and edge issues of laminated structures. Benefits include:
- No delamination at the sheet edge during drilling.
- Less debris — fewer particles that could contaminate the hole.
- Tighter stub control — consistent Z-reference across the full sheet.
- Easier handling — margin-reserved edges reduce scrap from edge damage.
HW600 vs HW900 — Process Capability
Both grades are qualified for stub length control; HW900 extends process capability on thicker back-drill stacks.
| Grade | Base (mm) | Stub CpK | Best application |
|---|---|---|---|
| HW600 | 0.16 | ≥ 1.33 | Standard back-drill, cost-first |
| HW900 | 0.19 | ≥ 1.67 | Tight-tolerance, high-speed digital |
HW600 is the cost-effective choice for standard back-drill applications. HW900 delivers the tighter stub CpK (≥1.67) needed for 25/56/112 Gbps high-speed digital designs where signal-integrity margin is critical.
Specifications at a Glance
| Parameter | Spec |
|---|---|
| Thickness | 0.16–0.19 mm |
| Construction | One-piece coated aluminum, margin-reserved |
| Application | 5G, server, communications, high-speed digital |
| Core benefit | Tight stub control → higher back-drill yield |
Sizes & Packaging
| Size (mm) | Grade | MOQ |
|---|---|---|
| 940 × 1245 | HW600 / HW900 | 100 sheets |
| 520 × 620 | HW600 / HW900 | 200 sheets |
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Applications
Used on 25G/56G SerDes signal integrity routes where residual stub degrades insertion loss.
Recommended Pairing
FAQ
Why not reuse a standard entry board for back-drilling?
Standard entry boards aren't engineered for the second controlled-depth pass. Stub length scatters and yield drops. A dedicated back-drill sheet holds the Z-reference needed for consistent stub control.
Which grade — HW600 or HW900?
HW600 for cost-first standard back-drill; HW900 where signal integrity demands tighter stub CpK (≥1.67) on high-speed digital designs above 25 Gbps.
What is the IPC-6012F requirement?
IPC-6012F Section 1.4.3 defines back-drill depth requirements. Our sheets are designed to support compliance by maintaining consistent Z-reference during the controlled-depth pass.
Can I get a free sample?
Yes — free samples and full TDS/MSDS are shipped worldwide within 5–7 days. Contact Mr. Lucky Xu to request HW600 or HW900 samples for your line.