Top 10 Design Mistakes That Kill Manufacturability (and How to Avoid Them)

September 26, 2025

Top 10 Design Mistakes That Kill Manufacturability (and How to Avoid Them)

When you invest time in a high-performance printed circuit board (PCB) design, the last thing you want is for the manufacturing handoff to stall your project—or worse, cause costly yield issues. That’s where Design for Manufacturability (DFM) comes in.

DFM isn’t just a late-stage checklist. It’s a proactive mindset that should be embedded early in the design cycle, catching trouble before it becomes expensive. At ACDi, we’ve seen first-hand how small oversights in layout can snowball into production delays. This guide highlights the top 10 DFM mistakes we encounter most often—and how to avoid them.

1. Not Leaving Enough Edge Clearance

Problem: Copper or copper features placed too close to the board edge risk being damaged or exposed when the board is routed, V‑scored or milled. The protective solder mask or edge plating may be trimmed away, leading to potential shorts, corrosion or mechanical fragility.

How to Avoid It:

Enforce a DRC rule (e.g. 15-20 mils from the board edge on all layers) for copper-to-board-edge clearance
Work with your board fab house early to understand their milling tolerances and safe margins
On internal layers, ensure copper pours don’t “float” to the edge unless intentionally designed for that(e.g. edge plating)

2. Creating Acid Traps (Sharp Angles in Routing)

Problem: Acute (less than 90°) angles in trace routing create “acid traps” during etching, where etchant gets trapped and over-etches the copper, causing thinning or breakage.

How to Avoid It:

Use 45° or large-radius bends instead of sharp turns
After routing, run a design rule check or visual audit for any angles < 90°
In tight spaces, smooth out joins rather than making L-shapes or zig-zags

3. Placing Vias in Pads Without Proper Planning

Problem: A via placed directly in a component pad (via-in-pad) can wick solder away from the pad during reflow, leading to poor solder joints or voids. It complicates soldering, rework and reliability.

How to Avoid It:

Only use via-in-pad when needed (e.g., for thermal conduction, high-density routing) and ensure proper via filling/plugging processes
If you must use it, specify via-fill (copper, epoxy) and confirm with your board house that they can support it
Where possible, place via annularly around the pad and stitch heat via arrays nearby

4. Overcomplicating the Board Layout (SMT on Both Sides, Mixed Processes)

Problem: Designs that split SMT parts across both sides or mix many assembly processes (wave, selective solder, through-hole) add cost, complexity, yield risk and process flow challenges.

How to Avoid It:

Aim to place as many SMT parts as possible on a single side
Only place parts on the second side if unavoidable (mechanics, connectors, board shape, etc.)
Standardize process types (SMT, through-hole, mixed) to simplify manufacturing flow

5. Incomplete or Incorrect Output Data & File Mismatch

Problem: Sending fabrication or assembly houses incomplete or inconsistent files (missing layers, mismatched layer names, misplaced vias, incorrect pick-and-place, absence of test info) leads to misinterpretation, delays or scrap.

How to Avoid It:

Always cross-check your Gerbers/ODB++/IPC‑2581 output with a DFM viewer before sending
Include detailed fabrication and assembly drawings (layer stack, copper weights, solder mask, silkscreen instructions)
For pick-and-place, ensure each entry includes designator, footprint, X/Y centroid, orientation, side and part reference
Consider sending a “mock assembly PDF” for the CM to validate placement logic

6. Unbalanced Copper or Unbalanced Stack-ups

Problem: Asymmetry in copper distribution between layers or poorly documented stack-ups can lead to warpage, bowing, twist or lamination delamination during manufacturing.

How to Avoid It:

Document your full layer stack: dielectric thickness, copper weights, signal/plane layers, core/plating thickness
Strive for symmetry in copper distribution (mirror layers when possible)
When heavy copper or power planes are used, compensate with copper on opposite layers or add dummy copper to balance( fabricators can add copper thieving to balance out copper layers)

7. Insufficient Trace Width or Poor Trace Spacing

Problem: If designers shrink trace widths too aggressively or violate spacing rules, traces may overheat, break or cause electrical faults (crosstalk, arcing).

How to Avoid It:

Use calculators (or PDN analyzers) to size trace width for current capacity and allowable temperature rise
Respect voltage, signal, and high-speed spacing rules (IPC‑2221 or your CM’s specific rules)
In dense routing zones, consider using internal layers or microvias rather than pushing minimum spacing

8. Poor Component Footprint Definition/Courtyard Violations

Problem: If your land patterns are misaligned, pin 1 indicators missing, pad sizes are off, or component courtyard zones overlap, placement, inspection and reproach may fail.

How to Avoid It:

Part manufactures often have recommended footprint patterns in their datasheets for use.
Use IPC‑compliant footprints (IPC‑7351 or equivalent)(Used mostly when recommended footprints aren’t an option)
Always verify pad-to-pad spacing, courtyard margins and orientation marks
Keep component height classes in mind (don’t mix extremely tall and very short where soldering or inspection is impeded)

9. Ignoring Testability and Access for Inspection

Problem: A board may look perfect on paper—but when it’s time for assembly or test, you may find test pads buried, inaccessible or too small for probes. This results in rework, yield losses or inability to debug.

How to Avoid It:

Reserve test pads and keep them spaced, accessible, and consistent height
Plan test buses in early layout, especially if using bed-of-nails, flying-probe or ICT methods
Ensure silkscreen doesn’t mask or confuse test pad identifiers
Engage your CM’s test engineers early to validate the test plan

10. Overlooking Component Lifecycle, Sourcing & BOM Risks

Problem: Sometimes the manufacturability barrier isn’t in the mask, but in the supply chain. Specifying EOL (end-of-life) parts, rare packages or parts with single vendors can stall production or force redesigns.

How to Avoid It:

Use life‑cycle aware component databases and plan alternate sources / parts
Avoid obscure or custom-only parts unless absolutely necessary
Document your BOM clearly, with manufacturer part numbers, recommended alternates, packages, footprints and suppliers
Periodically review your design parts against obsolescence and component risk trends

Wrapping Up: Embedding DFM for Success

Catching DFM problems late in the project is painful—and expensive. A smarter strategy is to:

Involve your contract manufacturer (CM) early for real-world insights
Use automated DFM/DRC tools to catch issues before release
Maintain an evolving DFM checklist to prevent repeat mistakes
Run pilot builds to uncover hidden risks before full-scale production

At ACDi, our PCB layout and DFM services are built on over 40 years of experience supporting OEMs across defense, aerospace and commercial markets. We help customers avoid these pitfalls, ensuring designs are ready to build—without surprises.

Learn more about ACDi’s PCB layout expertise and DFM service.

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