FreePCB2CAD: Convert PCB Designs to CAD for Free

FreePCB2CAD Alternatives and Best PracticesConverting PCB (printed circuit board) designs into CAD formats is a common task for electronics hobbyists, small businesses, and professional engineers. FreePCB2CAD is a tool aimed at exporting FreePCB designs into formats usable by CAD programs, but it’s not the only option. This article surveys alternatives, outlines when to choose each, and offers best practices to ensure accurate, manufacturable results when converting and preparing PCB designs for mechanical CAD, fabrication, or documentation.

Why convert PCB designs to CAD?

Converting a PCB to a CAD format is useful for:

• Mechanical integration: checking board fit, mounting holes, connectors, and clearances in an enclosure.
• Documentation: producing exploded views, assembly drawings, or silkscreen overlays for manuals.
• Collaboration: sharing board outlines and component placements with mechanical engineers who use CAD tools.
• Advanced manufacturing workflows: aligning PCB features with mechanical fixtures, standoffs, or 3D-printed housings.

Common target formats and what they’re used for

• STEP/IGES: 3D solids for mechanical assembly and collision detection in mechanical CAD. Preferred for full 3D component bodies.
• DXF: 2D vector outlines and layers; good for board outlines, silkscreen, and simple mechanical drawings.
• SVG/PDF: Vector formats for documentation, printing, or laser cutting.
• IPC-2581/ODB++: Rich electronics-specific data formats for advanced manufacturing data exchange (more than geometry).
• Gerber: Manufacturing artwork for PCB fabs; not ideal for mechanical CAD but essential for fabrication.

Alternatives to FreePCB2CAD

Below is a concise comparison of notable alternatives, with strengths and typical use-cases.

How to choose the right tool

• If you need detailed 3D component shapes and mechanical assembly checks, choose tools that export STEP (KiCad, Altium, Eagle+Fusion).
• If your focus is 2D outlines, mounting holes, and silkscreen, DXF or SVG exports are usually sufficient and simpler.
• For advanced manufacturing handoff with layer and net information, consider IPC-2581 or ODB++ capable tools (Altium, some enterprise tools).
• For hobbyist CNC milling of PCBs, use FlatCAM or generate G-code directly from Gerbers.
• Consider cost, learning curve, and ecosystem: open-source (KiCad) vs commercial (Altium, Autodesk).

Best Practices for Reliable Conversions

1. Keep design data clean

   • Remove unused footprints, layers, and net-tied copper that aren’t needed for mechanical views.
   • Flatten or lock any mechanical layer naming so the exporter maps layers consistently.

2. Use proper component 3D models

   • For accurate STEP exports, ensure components have associated 3D models. Many libraries include WRL/STEP models; add missing ones before export.
   • If models aren’t available, use simplified mechanical keepouts or bounding boxes to represent component volumes.

3. Manage units and scales

   • Confirm units (mm vs inches) in both ECAD and CAD tools before export/import to avoid scaling errors.
   • When possible, include explicit unit metadata (DXF has units; STEP is unitless but many tools assume mm).

4. Preserve reference geometry

   • Keep fiducials, mounting holes, board outline, and connector keepouts clearly defined in mechanical layers.
   • Export outlines as closed polylines or solids to avoid import issues where CAD tools treat outlines as open entities.

5. Check layer mapping

   • Verify how silkscreen, copper, solder mask, and mechanical layers map to the target CAD layers. Adjust mappings in the exporter if available.

6. Simplify 3D geometry when needed

   • High-detail 3D models can bloat STEP files. For assembly checks, prefer simplified solids or bounding boxes to keep file sizes manageable and CAD responsiveness acceptable.

7. Validate after import

   • Open the exported file in the target CAD and verify critical dimensions, hole positions, and component clearances.
   • Use interference detection/running clearance checks to catch collisions between components and enclosure parts.

8. Keep a two-track workflow: Gerbers + CAD export

   • Always produce and keep Gerbers/Excellons for fabrication, even if you export STEP/DXF for mechanical work. Gerbers are the fabrication ground truth.

9. Version, document, and automate

   • Record the ECAD version and export settings used for a conversion. Automate repeated exports with scripts where possible to avoid human error.

Common pitfalls and how to avoid them

• Missing 3D models: Use bounding boxes or import alternative model formats (WRL, STEP).
• Layer mismatches: Standardize layer names and test small exports before committing a full design.
• Scaling errors: Double-check unit settings on both export and import.
• Excessively large STEP files: Replace high-poly models with simplified solids or reduce tessellation where options exist.
• Misplaced component origin: Ensure footprint origins and board origin align with mechanical CAD’s expected reference point.

Example workflows

1. KiCad -> Fusion 360 (mechanical check)

   • Ensure footprints have STEP models or add them.
   • Export board and components as STEP from KiCad.
   • Import STEP into Fusion 360, align board origin, and run interference checks with enclosure parts.

2. FreePCB (legacy) -> DXF -> AutoCAD

   • Export board outline and silkscreen as DXF via FreePCB or script.
   • Clean DXF in a CAD tool (close polylines, set layers).
   • Use DXF for mechanical drawings or for laser-cut enclosure openings.

3. Altium -> Manufacturer (full handoff)

   • Export STEP for mechanical, and IPC-2581 / ODB++ for manufacturing data.
   • Include fabrication notes and separate Gerbers for the fab.

Tools and script examples

• Use Python scripting in KiCad to batch-export STEP models and boards.
• Use Altium’s scripting engine (DelphiScript or VBScript) to automate exports and include BOM/placement data.
• For FreePCB, small Perl/Python scripts can convert internal formats to DXF or SVG for CAD import.

Final checklist before sending to mechanical CAD or manufacturer

• [ ] Gerbers and drill files exported and verified with a Gerber viewer.
• [ ] STEP/DXF exported with correct units and board origin.
• [ ] All mounting holes and mechanical features present and dimensionally accurate.
• [ ] Components represented (detailed or bounding boxes) for collision checks.
• [ ] Layer mappings verified and documented.
• [ ] File sizes reasonable; heavy models simplified if needed.
• [ ] Export settings and tool versions recorded.

Converting PCBs to CAD is part technical translation and part communication between ECAD and MCAD domains. Choosing the right tool depends on the fidelity you need, and following the best practices above will save time and prevent costly mistakes in both prototyping and production.