How to use Gerber / Excellon PCB Viewer: a practical file-check workflow
Open a real file with Gerber / Excellon PCB Viewer and check important fields, output, format boundaries, and local privacy.
When to use it
Use this read-only tool when you want a quick preflight of copper, mask, silkscreen, outline, and drills before sending a fabrication ZIP. Gerber and Excellon are common PCB manufacturing outputs. This upgrades the existing viewer with layer and ZIP handling, but it is not a board-house CAM review.
Practical example
For a four-layer board, identify top/bottom copper, inner layers, masks, silkscreens, outline, and drills. Toggle each layer and compare outlines. A globally shifted drill layer often means Excellon and Gerber were exported from different origins.
Steps
- Drop individual Gerber/drill files or a fabrication ZIP.
- Confirm the detected top, bottom, mask, silkscreen, outline, and drill roles.
- Toggle layers and board side to inspect alignment and holes.
- Record issues and re-export from PCB CAD instead of editing production files.
Result checklist
- Layer roles match the design rather than relying only on extensions
- The outline is closed and copper/drills remain within plausible bounds
- PTH/NPTH drills are not globally shifted or scaled by a unit error
- Top/bottom orientation is explicit and silkscreen avoids exposed pads
First troubleshooting checks
The ZIP opens but every layer is unknown
Manually map layers when filenames are unusual; automatic detection is not a design manifest.
Pads or regions are missing
Aperture macros, region fills, or legacy dialects may be incomplete; verify in source CAD and fabricator CAM.
Real limitations
- Filename-based layer detection can be wrong and must be reviewed
- Complex aperture macros, step-repeat, and vendor dialects may be incomplete
- No replacement for DRC, netlist comparison, or fabrication CAM review
Privacy and file safety
Parsing runs in the current browser tab and the file is not uploaded to FreeTool to use this tool. Still use a trusted device for customer, engineering, research, or medical material. Keep the original unchanged and clear downloads, screenshots, and browser data after a shared device.