Every day, as a turnkey PCBA manufacturer, we receive inquiries from clients who are designing or sourcing electronic assemblies. Two questions come up more often than any other:
“We have the original design files. Why do we still need Gerber files?”
“Can’t you work from CAD or PDF drawings?”
These are fair questions. Today, we will explain—in plain language—why Gerber files are the absolute “passport” to PCBA processing. And why, without them, your project is exposed to unnecessary risk.
A Gerber file is a standard graphic format exported from PCB design software. It is the universal language for PCB fabrication and PCBA assembly worldwide. The current industry standard is RS-274X, maintained by Ucamco.
Think of a Gerber file as a multilayer architectural blueprint. It uses coordinates and graphic codes to describe every critical aspect of your board with perfect precision:
Copper layers – The conductive paths between components
Drill files – Position and size of vias and throughhole pads
Solder mask – Areas covered to prevent shorts
Silkscreen – Component designators, polarity markers
Board outline – Physical shape and dimensions
Without Gerber files, a PCB fab or SMT line is like a blindfolded person trying to assemble a puzzle. They cannot see the details, and automated machines cannot start.
The image of the PCBA
Many clients assume that CAD or PDF drawings are sufficient. Those formats are humanreadable, but machineunfriendly. We once received only a PDF from a customer. A buried via was not clearly marked. The entire batch of PCBs was drilled incorrectly. The loss was significant.
Gerber files describe every layer in a standard format, eliminating the “I thought you knew” trap. They are the most reliable bridge for collaboration across teams and companies.
Pickandplace machines do not work by sight. They read coordinate layers (e.g., .top, .bot) from Gerber files for precise positioning. On our SMT lines, using Gerber files to automatically import coordinates delivers placement accuracy within ±0.01mm and is nearly 80% more efficient than manual data entry.
With Gerber files, we can perform preproduction audits of solder mask openings, pad sizes, and electrical connectivity. For example, a medical device client had an abnormal BGA pad opening. We caught it during Gerber review, optimized the stencil design, and improved firstpass yield from 96.8% to 99.85%.
Gerber files are not only for production—they are the foundation of traceability. When an anomaly occurs, we can compare the actual board layers against the original Gerber data and quickly determine whether the root cause is a design issue or a production deviation. We recommend that clients provide a complete Gerber package with 10 standard layers for longterm traceability.
The image of the PCBA
Q1: We only work with CAD. Can you convert the files for us?
A: Yes—but with one condition. Please provide the original design source files (e.g., Altium, AD, PADS). Our engineering team can assist with conversion. However, we strongly recommend that you confirm the final Gerber files before release, so ownership of the design data remains clear.
Q2: What are the standard layers in a Gerber package?
A: A complete package typically includes these 10 layers (common extensions shown):
| Layer | Typical Extension |
| Top copper | .gtl |
| Bottom copper | .gbl |
| Top solder mask | .gts |
| Bottom solder mask | .gbs |
| Top silkscreen | .gto |
| Bottom silkscreen | .gbo |
| Drill file | .drl |
| Board outline | .gml or .gko |
| Inner layers (multilayer) | .g2, .g3, etc. |
| Pickandplace coordinates | .txt or .csv |
For a professional PCBA manufacturer, Gerber files are essential. They are the signal to start work. Without them, we cannot fabricate your PCBs, accurately place components, solder, test, or guarantee quality.
If you are sourcing PCBA for industrial automation, automotive, medical, or highreliability equipment, please remember: a complete, verified Gerber package is the fastest path to a successful production run.
At Fumaxtech, we work with your Gerber files to deliver boards that match your design exactly—first time, every time. Send us your Gerber package today, and let us quote your next project.
