Essential Files Needed for PCB Manufacturing Explained

For PCB manufacturing, the essential files include Gerber files that define copper layers, solder mask, and silkscreen, drill files for holes, and assembly files for component placement. These files together guide the manufacturer to produce the physical board accurately.

Syntax

PCB manufacturing requires a set of standard files, each serving a specific purpose:

• Gerber files: Define each copper layer, solder mask, and silkscreen artwork.
• Drill files: Specify hole locations and sizes for vias and component leads.
• Assembly files: Show component placement and orientation on the board.
• BOM (Bill of Materials): Lists all components needed for assembly.

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Gerber Files: <boardname>_LayerName.GTL (Top Copper), <boardname>_LayerName.GBL (Bottom Copper), etc.
Drill File: <boardname>.TXT or <boardname>.DRL
Assembly File: <boardname>_Assy.csv or .txt
BOM: <boardname>_BOM.csv

Example

This example shows typical file names generated for a two-layer PCB named "MyBoard".

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MyBoard_GTL.GBR  // Top copper layer Gerber
MyBoard_GBL.GBR  // Bottom copper layer Gerber
MyBoard_GTS.GBR  // Top solder mask
MyBoard_GBS.GBR  // Bottom solder mask
MyBoard_GTO.GBR  // Top silkscreen
MyBoard_GBO.GBR  // Bottom silkscreen
MyBoard.TXT      // Drill file
MyBoard_Assy.csv // Assembly file
MyBoard_BOM.csv  // Bill of Materials

Output

Files ready for PCB manufacturer:
- Gerber layers for copper, mask, silkscreen
- Drill file for holes
- Assembly file for parts
- BOM for components

Common Pitfalls

Common mistakes when preparing PCB manufacturing files include:

• Missing or incomplete Gerber layers causing manufacturing errors.
• Incorrect drill file format or missing drill data leading to wrong hole sizes.
• Not providing assembly files, which delays component placement.
• Forgetting to include the BOM, causing confusion on parts needed.

Always verify files with a Gerber viewer before sending to the manufacturer.

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Wrong way:
- Sending only copper layers without solder mask or silkscreen
- Drill file missing or in wrong format

Right way:
- Include all Gerber layers (copper, mask, silkscreen)
- Provide drill file in standard Excellon format
- Add assembly and BOM files for full production info

Quick Reference

File Type	Purpose	Typical File Extension
Gerber Files	Define copper layers, solder mask, silkscreen	.GBR, .GTL, .GBL
Drill File	Specify hole locations and sizes	.TXT, .DRL
Assembly File	Show component placement and orientation	.CSV, .TXT
Bill of Materials (BOM)	List all components for assembly	.CSV, .XLSX

Key Takeaways

Gerber files are essential to define PCB copper, mask, and silkscreen layers.

Drill files specify hole sizes and positions for vias and components.

Assembly files guide component placement and orientation on the board.

Including a BOM helps manufacturers source the correct components.

Always verify all files with a Gerber viewer before submission.