pcb-to-stencil/README.md

Gerber Solder Paste Layer to Solder Stencil Converter

A Go tool to convert Gerber files (specifically solder paste layers) into 3D printable STL stencils.

Features

• Parses standard RS-274X Gerber files.
• Supports standard apertures (Circle, Rectangle, Obround).
• Supports Aperture Macros (AM) with rotation (e.g., rounded rectangles).
• Automatically crops the output to the PCB bounds.
• Generates a 3D STL mesh optimized for 3D printing.

Usage

Run the tool using go run:

go run main.go gerber.go [options] <path_to_gerber_file> [optional_board_outline_file]

Options

• --height: Stencil height in mm (default: 0.16mm).
• --wall-height: Wall height mm (default: 2.0mm).
• --wall-thickness: Wall thickness in mm (default: 1mm).
• --keep-png: Save the intermediate PNG image used for mesh generation (useful for debugging).

Example

go run main.go gerber.go -height=0.16 -keep-png my_board_paste_top.gbr my_board_outline.gbr

This will generate my_board_paste_top.stl in the same directory.

3D Printing Recommendations

For optimal results with small SMD packages (like TSSOP, 0402, etc.), use the following 3D print settings:

• Nozzle Size: 0.2mm (Highly recommended for sharp corners and fine apertures).
• Layer Height: 0.16mm total height.
  • First Layer: 0.10mm
  • Second Layer: 0.06mm
• Build Surface: Smooth PEI sheet (Ensures the bottom of the stencil is perfectly flat for good PCB adhesion).

These settings assume you run the tool with -height=0.16 (the default).

How it Works

1. Parsing: The tool reads the Gerber file and interprets the drawing commands (flashes and draws).
2. Rendering: It renders the PCB layer into a high-resolution internal image.
3. Meshing: It converts the image into a 3D mesh using a run-length encoding approach to optimize the triangle count.
4. Export: The mesh is saved as a binary STL file.

License

This project is licensed under the MIT License - see the LICENSE file for details.