How to Prepare Gerber Files for PCB Manufacturing

Why Gerber File Preparation Matters

Before any PCB prototype manufacturer can produce your board, they need one thing: accurate Gerber files. These industry-standard files define every layer of your design — copper traces, solder mask, silkscreen, drill data, and board outline. Yet Gerber-related errors remain the number one cause of manufacturing delays and prototype rejects.

Whether you are ordering a small batch PCB run for R&D validation or preparing for mass production, getting your Gerber files right the first time saves days of back-and-forth with your manufacturer. Here are the key steps every engineer should follow.

Eliminate the most common submission errors that cause production delays
Understand exactly which files your PCB manufacturer needs
Learn to verify your output before sending it off

1. Generate Files in the Correct Format

Modern PCB design tools export Gerber files, but not all exports are created equal. The industry standard is Gerber X2 (RS-274X), which includes layer attributes and metadata that help manufacturers interpret your design without guessing.

Always use Gerber X2 or RS-274X format — avoid older RS-274-D which requires separate aperture lists
Export each copper layer, solder mask, silkscreen, paste mask, and board outline as separate files
Include an EDA (Excellon) drill file with both metric units and decimal notation

Using a Hong Kong PCB manufacturer like FM-TRUE Electronics means your files are reviewed by experienced engineers who can catch format issues — but starting with the right format avoids delays entirely.

2. Include All Required Layers

A complete Gerber submission typically requires 8 to 12 or more files depending on board complexity. Missing even one layer can halt production.

Copper layers: Top and bottom copper, plus any inner layers for multilayer boards
Solder mask: Top and bottom solder mask openings (aperture files)
Silkscreen: Top and bottom legend/text layers
Paste mask: Solder paste stencil layers for SMT assembly
Board outline: Mechanical layer defining the board edge
Drill file: Excellon format with hole sizes and locations

When ordering small batch PCB prototypes, providing a complete file set upfront means your board goes straight to production without clarification delays.

3. Set Correct Units and Scale

Mixed units between your Gerber and drill files is one of the most common — and most costly — mistakes in PCB manufacturing. A board designed in millimeters but exported with imperial drill data will come out the wrong size entirely.

Use metric (millimeters) for all Gerber layers
Set drill files to metric with decimal notation (not leading/trailing zero suppression)
Verify scale by measuring a known dimension — like board width — in a Gerber viewer
Double-check that your design tool did not apply any unintended scaling during export

4. Verify Layer Alignment and Polarity

Even correctly formatted files can be useless if layers do not align properly. Misregistered solder masks, inverted polarity on drill files, or offset silkscreen are issues that only surface during manufacturing if not caught early.

Load all Gerber files into a viewer (such as GerbView, GC-Prevue, or your EDA tool) and visually inspect alignment
Check that solder mask openings line up with pads — not shifted by even 0.1 mm
Confirm drill holes are centered on through-hole pads
Verify that the board outline does not cut through traces or components

A reliable PCB prototype manufacturer will run DFM (Design for Manufacturing) checks, but pre-verifying alignment yourself prevents surprises and project delays.

5. Name Your Files Clearly

When a manufacturer receives 10+ files with names like layer1.gbr and drill.txt, ambiguity leads to mistakes. Clear, standardized file naming ensures your board is built exactly as designed.

Use standard extensions: .gtl (top copper), .gbl (bottom copper), .gts (top mask), .gbs (bottom mask)
Include a README or file list if your naming convention differs from standard
For multilayer boards, clearly number inner layers (e.g., G1.gbr, G2.gbr)
Avoid spaces and special characters in file names

6. Run a DRC Before Exporting

Design Rule Check (DRC) catches violations before your files even reach the manufacturer. Running DRC in your EDA tool ensures your design meets the manufacturing constraints of your chosen PCB fabrication partner.

Run DRC with your manufacturer minimum trace width, spacing, and drill sizes
Fix all errors — do not export with violations and hope the manufacturer will flag them
Check for unconnected nets, minimum annular ring violations, and acid traps
Export only after DRC passes with zero errors

7. Compress and Organize Your Submission

The final step before sending your files is packaging them correctly. A well-organized submission speeds up the review process and reduces the chance of miscommunication.

Compress all Gerber and drill files into a single ZIP archive
Do not nest folders inside the ZIP — keep all files at the root level
Include a specification sheet with: layer count, board thickness, copper weight, surface finish, and any special requirements
If ordering SMT assembly, also include a BOM (Bill of Materials) and pick-and-place file

Why Choose FM-TRUE Electronics for Your PCB Prototypes?

At FM-TRUE Electronics (HK) Ltd, we understand that every engineering project has unique requirements. That is why we specialize in serving semiconductor labs, medical device companies, industrial control systems, and test equipment manufacturers who need fast, reliable PCB prototype manufacturing with no minimum order constraints.

1-piece minimum: Order exactly the quantity you need, from a single prototype to small batch production
5-25 piece small batch: Ideal for R&D validation, design iteration, and pre-production testing
24-48 hour turnaround: Rapid prototype delivery keeps your project on schedule
ISO 9001 certified: Every board passes through our rigorous quality management system

Located in Hong Kong, we serve customers across Asia and worldwide. Our engineering team reviews every Gerber submission personally, catching potential issues before production begins.

Conclusion

Preparing Gerber files correctly is not just a technical formality — it is the foundation of a successful PCB manufacturing project. By following the steps outlined above, you ensure your design intent is communicated accurately, production runs smoothly, and your prototype arrives on time and to specification. If you need support with Gerber file preparation or are looking for a reliable PCB prototype manufacturer for your next project, contact our engineering team today.