7 Common PCB Design Mistakes Overseas Clients Make (And How LeadsInTec Fixes Them)

If you are from the US, Europe, or anywhere outside China and you send your PCB files to factories there, you may face big problems. Why? Time zones are different. Language can be hard. And factories in China like Shenzhen have strict rules for making PCBs and PCBA (Printed Circuit Board Assembly). Many clients make simple mistakes in design that cause delays, extra costs, or bad boards that do not work.

At LeadsInTec Group, we have 18+ years making PCBs for 1,000+ clients worldwide. We serve IoT, AI, medical, automotive, aerospace, agriculture, and military. Our 150+ engineers in Shenzhen fix these issues fast with free PCB file checks (in 2 hours!), no minimum order (MOQ), and full EMS (design to box build). We reply 24/7 in English.

Here are 7 common PCB design mistakes overseas clients make. Each one comes from real problems we see—like incorrect Gerber files or footprints that don't match China tools. We explain why it happens, what goes wrong, and how we fix it. Use our tips to avoid trouble!

Mistake #1: Incorrect Component Footprints

What happens: Footprints are the pads where parts sit. Overseas clients often copy footprints from US/EU libraries (like from Digi-Key). But China factories use IPC-7351 standards or JLCPCB/PCBWAY footprints. Pads may be too small (e.g., 0603 resistor pad 0.3mm vs. needed 0.35mm), pin spacing may be wrong (e.g., QFN package off by 0.1mm), or there may be no pin 1 mark for diodes/ICs.

Why overseas clients do this: You design in Altium/KiCad for local prototypes, but China assembly machines (pick-and-place) need exact fits. Mismatch causes tombstoning (parts lift in reflow oven), bad solder, or parts fall off. From Reddit/EEVblog: 60% of first orders fail here.

Cost: Redesign + remake = 2-4 weeks delay, $500-2000 extra.

How LeadsInTec fixes it: Free DFMA (Design for Manufacturability/Assembly) check. Our 150 engineers review your BOM and footprints vs. datasheets. We fix in Gerber files (e.g., add 7mil courtyard clearance). Example: US client EV battery PCB—wrong BGA footprint fixed in 4 hours, saved 30% assembly cost.

Mistake #2: Gerber File Errors (Missing Layers or Drill Files)

What happens: Gerber files tell factories what to etch/drill. Common errors: No board outline (factory guesses size), missing inner layers (multilayer board has no signals), empty drill file (no holes), or wrong units (inches vs. mm—e.g., 0.1" hole becomes 2.54mm but drill is 0.8mm).

Why overseas: You export from Eagle/Altium without "RS-274X" format. China CAM software (like from PCBWay) flags errors, but "no-touch" factories make wrong boards. Stack Exchange: Customs delays + useless batches.

Cost: Whole batch scrapped (e.g., 100 boards = $1,000+), 3-week reship.

How LeadsInTec fixes it: Auto DFM tool scans Gerbers (copper, solder mask, silkscreen, Excellon drill). We email fixes in 2 hours. For Europe medical wearable: Missing X-ray layer for vias fixed, passed IPC Class 3. No MOQ prototypes ready in 7 days.

Mistake #3: Trace Width Errors and Poor Ground Plane

What happens: Traces too thin (e.g., 0.1mm for 1A current—overheats/melts). No ground plane (noise in IoT signals). Or sharp 90° corners trap acid in etching.

Why overseas: US designs use wide traces for prototypes, but China high-volume SMT needs 0.15-0.2mm min. Impedance mismatch (50Ω trace wrong stackup) kills high-speed AI/5G.

Cost: Burnt boards in testing, EMI fails certs (e.g., FCC for automotive).

How LeadsInTec fixes it: DFMA optimizes traces (e.g., 0.25mm for 2A power). Full ground pour + stitching vias. Aerospace drone client: Impedance fixed to 100Ω diff pair, 30% cost cut via stackup tweak. Get your free trace calculator.

Mistake #4: BOM Discrepancies (Wrong Parts or Obsolescence)

What happens: Bill of Materials (BOM) lists parts, but MPN wrong (e.g., DigiKey vs. LCSC), obsolete (2026 shortages), or no package (SMD vs. THT). China sources locally—your US part unavailable.

Why overseas: Global supply chain—China tariffs/exports block JST connectors (Stack Exchange story: 1-month customs delay).

Cost: Assembly halt, $2K+ sourcing.

How LeadsInTec fixes it: 200+ sourcing experts match BOM to China stock (99% hit rate). Alternatives ready (e.g., obsolescence mgmt). Agriculture sensor client: 87215-4 connector fixed, full turnkey EMS.

Mistake #5: Insufficient Clearances and Annular Rings

What happens: Parts too close (under 0.2mm for 0603), pads near edge (<5mm), annular ring <0.15mm (drill eats copper).

Why overseas: EU prototypes ignore China DFM (IPC-A-600). Pick-place robots crash, X-ray inspection fails.

Cost: Solder bridges, shorts—50% yield loss.

How LeadsInTec fixes it: Auto-check: 0.5mm IC clearance, 7mil drill-to-copper. Military PCB: Vibration-proof rings added, MIL-STD pass.

Mistake #6: Signal Integrity Issues (Impedance Mismatch)

What happens: High-speed traces (USB3/AI) wrong width/length—no 50Ω control. Vias too many, no decoupling caps near ICs.

Why overseas: Local sim tools miss China materials (FR4 vs. Rogers).

Cost: Data errors in ADAS/EV—redesign $10K+.

How LeadsInTec fixes it: Stackup calculator for impedance. HDI/BGA expertise. 2026 AI trend: Edge computing PCBs optimized.

Mistake #7: Thermal Management Mistakes

What happens: No vias under hot chips, thin power planes. Medical wearables overheat.

Why overseas: Prototypes ignore reflow (260°C China ovens).

Cost: Component fail, FDA reject.

How LeadsInTec fixes it: Thermal sim + relief pads. Box build with heatsinks.