KiCad to JLCPCB BOM/CPL Converter

Convert KiCad exported BOM and position files to JLCPCB PCBA order format.

Quick Start

IMPORTANT: This skill includes ready-to-use Python scripts! Use them instead of copying inline code.

Scripts Location

~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/
├── convert_to_jlcpcb.py      # Main conversion script
├── add_lcsc_numbers.py        # Add LCSC part numbers
└── create_parts_mapping.py    # Generate mapping template

Basic Usage

# Step 1: Convert KiCad exports to JLCPCB format
python3 ~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/convert_to_jlcpcb.py \
  bom.csv top.pos bottom.pos output_dir/

# Step 2: Add LCSC part numbers (interactive mode)
python3 ~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/add_lcsc_numbers.py \
  output_dir/jlcpcb-bom.csv --interactive

# Or use mapping file
python3 ~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/add_lcsc_numbers.py \
  output_dir/jlcpcb-bom.csv --map parts_mapping.json --filter-test-points

Template Files

Reference templates (downloaded from JLCPCB) are located at:

• ~/.claude/skills/jlcpcb-bom-generate-from-kicad/templates/sample-bom.xlsx
• ~/.claude/skills/jlcpcb-bom-generate-from-kicad/templates/sample-cpl.xlsx

Input Files (KiCad Exports)

KiCad BOM CSV

Exported from KiCad's BOM tool. Format (semicolon-delimited):

"Id";"Designator";"Footprint";"Quantity";"Designation";"Supplier and ref";
1;"U6";"TO-263-2_L10.0-W9.1-P5.08-LS15.2-TL";1;"L7812CD2T-TR";;;
2;"R12,R3,R13";"R0603";3;"5.1k";;;

KiCad Position Files (.pos)

Exported from KiCad's Fabrication Outputs > Component Placement. Format:

# Ref     Val               Package                   PosX       PosY       Rot  Side
C1        10uF              C1206                     46.7500   -12.4325  180.0000  top
R1        10k               R0603                     38.8600   -29.5025   90.0000  top

Output Files (JLCPCB Format)

JLCPCB BOM CSV

Comment,Designator,Footprint,JLCPCB Part #
L7812CD2T-TR,U6,TO-263-2_L10.0-W9.1-P5.08-LS15.2-TL,C13456
5.1k,"R13,R3,R12",R0603,C23186

JLCPCB CPL (Component Placement List) CSV

Designator,Mid X,Mid Y,Layer,Rotation
C1,46.7500mm,12.4325mm,Top,180
R1,38.8600mm,29.5025mm,Top,90

Conversion Rules

BOM Conversion

KiCad Field	JLCPCB Field	Notes
Designation	Comment	Component value/name
Designator	Designator	Multiple refs comma-separated, sort alphanumerically
Footprint	Footprint	Keep as-is
(none)	JLCPCB Part #	Must be added - use scripts or jlcpcb-component-finder skill

Key transformations:

• Designators are sorted alphanumerically (C1, C2, C10, R1, R2, etc.)
• Test points (TP*) can be auto-filtered
• Mounting holes (H*, MH*) can be excluded

CPL Conversion

KiCad Field	JLCPCB Field	Transformation
Ref	Designator	Keep as-is
PosX	Mid X	Add "mm" suffix
PosY	Mid Y	Negate the value (KiCad uses negative Y), add "mm" suffix
Side	Layer	Capitalize ("top" → "Top", "bottom" → "Bottom")
Rot	Rotation	Normalize to 0-360 (add 360 if negative)

Critical transformation: Y-coordinates must be negated because KiCad and JLCPCB use different coordinate systems.

Workflow

Step 1: Export from KiCad

BOM:

1. Open schematic in KiCad
2. Tools → Generate BOM
3. Select CSV format with semicolon delimiter
4. Export as bom.csv

Position Files:

1. Open PCB layout in KiCad
2. File → Fabrication Outputs → Component Placement (.pos)
3. Export top.pos and bottom.pos (or just one side)

Step 2: Convert Files

Use the bundled script:

python3 ~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/convert_to_jlcpcb.py \
  dist/kicad-bom-outputs/bom.csv \
  dist/kicad-placement-outputs/top.pos \
  dist/kicad-placement-outputs/bottom.pos \
  dist/jlcpcb-ready/

Output:

• dist/jlcpcb-ready/jlcpcb-bom.csv - BOM (without LCSC numbers)
• dist/jlcpcb-ready/jlcpcb-cpl.csv - CPL (ready to upload)

Step 3: Add LCSC Part Numbers

Option A: Interactive Mode (good for small projects)

python3 ~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/add_lcsc_numbers.py \
  dist/jlcpcb-ready/jlcpcb-bom.csv \
  --interactive \
  --output dist/jlcpcb-ready/jlcpcb-bom-with-lcsc.csv

Option B: Mapping File (good for reusable projects)

# 1. Create mapping template
python3 ~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/create_parts_mapping.py \
  --output parts_mapping.json

# 2. Edit parts_mapping.json to add your LCSC numbers
# {
#   "LM7805ABD2T-TR": "C86206",
#   "10k": "C25804",
#   ...
# }

# 3. Apply mapping
python3 ~/.claude/skills/jlcpcb-bom-generate-from-kicad/scripts/add_lcsc_numbers.py \
  dist/jlcpcb-ready/jlcpcb-bom.csv \
  --map parts_mapping.json \
  --filter-test-points \
  --output dist/jlcpcb-ready/jlcpcb-bom-with-lcsc.csv

Option C: Use jlcpcb-component-finder skill
For unknown parts, use the companion skill to search JLCPCB database:

User: "Find LCSC part for LM7805 TO-263 package"
Claude: [Uses jlcpcb-component-finder skill]

Step 4: Upload to JLCPCB

1. Go to https://jlcpcb.com/quote
2. Upload Gerber files
3. Enable "SMT Assembly"
4. Upload:

• BOM: jlcpcb-bom-with-lcsc.csv
• CPL: jlcpcb-cpl.csv

5. Review component matching
6. Verify placements in viewer
7. Checkout!

Filtering Components

Components typically excluded from JLCPCB PCBA:

• Test points (TP*)
• Mounting holes (H*, MH*)
• THT connectors (unless specifically supported)
• Components you want to solder manually

The add_lcsc_numbers.py script includes --filter-test-points flag to auto-exclude:

• Designators starting with TP, H, MH
• Comments like "GND", "+5V", "+12V" (test point labels)

Real-World Example

From the zudo-power-usb-pd project:

# 1. Convert KiCad exports
python3 convert_to_jlcpcb.py \
  zudo-pd.csv \
  zudo-pd-top.pos \
  zudo-pd-bottom.pos \
  jlcpcb-ready/

# Output:
# ✅ Converted BOM saved to: jlcpcb-ready/jlcpcb-bom.csv
#    Total components: 43
# ✅ Converted CPL saved to: jlcpcb-ready/jlcpcb-cpl.csv
#    Total components: 72

# 2. Add LCSC numbers from project BOM documentation
python3 add_lcsc_numbers.py \
  jlcpcb-ready/jlcpcb-bom.csv \
  --map parts_mapping.json \
  --filter-test-points \
  --output jlcpcb-ready/jlcpcb-bom-with-lcsc.csv

# Output:
# ✅ Updated BOM saved to: jlcpcb-ready/jlcpcb-bom-with-lcsc.csv
#    Total components: 38
#    With LCSC part #: 38
#    Missing part #: 0

# 3. Ready for JLCPCB upload!

Troubleshooting

BOM Upload Fails

• Check CSV format (no special characters in designators)
• Verify LCSC part numbers are valid (all start with 'C')
• Ensure all required fields are present

CPL Upload Fails

• Verify coordinate format (must include "mm" suffix)
• Check rotation values (must be 0-360)
• Ensure Layer field is "Top" or "Bottom" (capitalized)

Components Don't Match

• Some LCSC parts may be out of stock temporarily
• Check JLCPCB's suggested alternatives
• Use jlcpcb-component-finder skill to find replacements

Wrong Coordinate System

If components appear in wrong locations:

• Verify Y-coordinates were negated (script does this automatically)
• Check KiCad board origin settings
• Ensure Gerber and CPL use same origin

Notes

• JLCPCB may adjust placement coordinates based on their manufacturing process
• Board origin in KiCad affects coordinates - use "Drill/Place file origin" for consistency
• Some footprints may need renaming to match JLCPCB's library conventions
• Always verify the first assembly order carefully

Integration with Other Skills

This skill works well with:

• jlcpcb-component-finder: Search JLCPCB database for LCSC part numbers
• easyeda2kicad: Download footprints/symbols for JLCPCB parts

Example workflow:

1. Use easyeda2kicad to download footprints from LCSC
2. Design PCB in KiCad
3. Use THIS skill to convert BOM/CPL
4. Use jlcpcb-component-finder to find missing LCSC numbers
5. Upload to JLCPCB for assembly