jlcpcb

What this skill does

# JLCPCB — PCB Fabrication & Assembly

JLCPCB is a PCB fabrication and assembly service based in Shenzhen, China. It is a sister company to LCSC Electronics (common ownership) — they share the same parts library.

**Typical usage**: Order bare prototype PCBs + framed stencil from JLCPCB during prototyping (parts sourced separately from DigiKey/Mouser, hand-assembled in lab). For production runs (100s qty), order fully assembled boards from JLCPCB using LCSC parts. PCBWay is an alternative assembler. For component searching, see the `lcsc` skill. For BOM management, gerber/CPL export, and stencil ordering, see the `bom` skill.

## Related Skills

| Skill | Purpose |
|-------|---------|
| `kicad` | Read/analyze KiCad project files, DFM scoring against JLCPCB capabilities |
| `bom` | BOM management, gerber/CPL export, stencil ordering |
| `digikey` | Search DigiKey (prototype sourcing, primary — also preferred for datasheet downloads via API) |
| `mouser` | Search Mouser (prototype sourcing, secondary) |
| `lcsc` | Search LCSC (production sourcing — JLCPCB uses LCSC parts library) |
| `pcbway` | Alternative PCB fabrication & assembly |
| `emc` | EMC pre-compliance risk analysis — run before fab to catch EMC issues |
| `spice` | SPICE simulation — verify analog subcircuits before committing to fab |

## Assembly Parts Library

### Part Categories

| Category | Description | Assembly Fee |
|----------|-------------|--------------|
| **Basic** | ~698 common parts (resistors, caps, diodes, etc.) pre-loaded on pick-and-place machines | No extra fee |
| **Preferred Extended** | Frequently used extended parts | No feeder loading fee (Economic assembly) |
| **Extended** | 300k+ less common parts loaded on demand | $3 per unique extended part |

### LCSC Part Numbers

Every assembly component is identified by an **LCSC Part Number** (`Cxxxxx`, e.g., `C14663`). This is the definitive identifier for BOM matching. See the `lcsc` skill for searching parts.

### Parts Search (JLCPCB-Specific)

- Parts library: `https://jlcpcb.com/parts/componentSearch?searchTxt=<query>`
- Basic parts only: `https://jlcpcb.com/parts/basic_parts`

## BOM Format for Assembly

JLCPCB accepts CSV, XLS, or XLSX BOMs with these columns:

| Column | Required | Description |
|--------|----------|-------------|
| `Comment` / `Value` | Yes | Component value (e.g., 100nF, 10k) |
| `Designator` | Yes | Reference designators, comma-separated (e.g., C1,C2,C5) |
| `Footprint` | Yes | Package/footprint name |
| `LCSC Part #` | Recommended | LCSC part number (Cxxxxx) — guarantees exact match |

The column header for LCSC numbers must be exactly **"LCSC Part #"** or **"LCSC Part Number"** — typos cause upload failures.

### KiCad BOM Export for JLCPCB

1. In KiCad schematic editor, add an `LCSC` field to each symbol with the LCSC part number
2. Export BOM as CSV with columns: Reference, Value, Footprint, LCSC
3. Rename columns to match JLCPCB's expected format:
   - `Reference` -> `Designator`
   - `Value` -> `Comment`
   - `Footprint` -> `Footprint`
   - `LCSC` -> `LCSC Part #`

For gerber export settings, CPL format, and stencil ordering, see the `bom` skill.

## JLCPCB Official API (Approval Required)

Apply at `https://api.jlcpcb.com`. Access is gated — requires review based on order history and business profile.

Available APIs (once approved):
- **Components API** — real-time pricing, inventory, component specs
- **PCB API** — upload gerbers, get quotes, place orders, track status
- **Stencil API** — stencil quoting and ordering
- **3D Printing API** — SLA/MJF/SLM/FDM ordering

## PCB Design Rules (JLCPCB Capabilities)

### Standard PCB (1-2 layers)

| Parameter | Minimum |
|-----------|---------|
| Trace width | 0.127mm (5mil) |
| Trace spacing | 0.127mm (5mil) |
| Via diameter | 0.45mm |
| Via drill | 0.2mm |
| Annular ring | 0.125mm |
| Min hole size | 0.2mm |
| Board thickness | 0.4-2.4mm (default 1.6mm) |
| Min board size | 6x6mm |
| Max board size | 500x400mm (2-layer) |

### Multi-layer (4+ layers)

| Parameter | Minimum |
|-----------|---------|
| Trace width | 0.09mm (3.5mil) |
| Trace spacing | 0.09mm (3.5mil) |
| Via diameter | 0.25mm |
| Via drill | 0.15mm |
| Board thickness | 0.6-2.4mm |

### Importing DRU into KiCad

If you have a JLCPCB `.kicad_dru` design rules file, import it in KiCad Board Editor > Board Setup > Design Rules > Import Settings.

## Assembly Constraints

### Economic vs Standard Assembly

| Feature | Economic | Standard |
|---------|----------|----------|
| Sides | Top only | Top + Bottom |
| Component types | SMD only | SMD + through-hole |
| Min component size | 0201 | 01005 |
| Fine-pitch BGA/QFP | Down to 0.5mm pitch | Down to 0.4mm pitch |
| Turnaround | ~3-5 days | ~3-5 days |
| Extended part fee | $3 per unique part | $3 per unique part |

### General Constraints

- **Minimum order**: 5 PCBs for assembly
- **Unique parts limit**: No hard limit, but each extended part adds $3
- **Basic parts**: No extra fee, pre-loaded on machines

## Rotation Offsets

JLCPCB's pick-and-place uses different rotation conventions than KiCad for some footprints. Common offsets:

| Footprint Family | Typical Offset |
|-----------------|----------------|
| SOT-23, SOT-23-5, SOT-23-6 | +180° |
| SOT-223 | +180° |
| SOIC-8, SOIC-16 | +90° or +270° |
| QFN (all sizes) | +90° |
| SMA/SMB/SMC diodes | +180° |
| USB-C connectors | Varies — check datasheet |

To fix rotation issues:
1. Add rotation corrections directly in the CPL file before uploading (adjust the Rotation column)
2. For custom footprints, verify pin 1 orientation matches JLCPCB expectations
3. JLCPCB's review step catches major errors, but subtle 180° rotations on symmetric parts (caps, resistors) may slip through
4. After first assembly order, note any rotation corrections needed and apply them to future CPL exports

## Ordering Workflow

### Prototype Order (Bare PCB + Stencil)

1. **Export gerbers** from KiCad (see `bom` skill for export settings)
2. Upload gerbers to `https://cart.jlcpcb.com/quote` — configure layers, thickness, color, qty
3. Add a **framed stencil** to the cart (uses paste layers from your gerbers)
4. Order — PCBs and stencil typically arrive in ~1 week

### Production Order (Assembled Boards)

1. **Export gerbers** from KiCad (see `bom` skill for export settings)
2. **Export BOM** as CSV with LCSC part numbers (format above)
3. **Export CPL** (placement file) as CSV (see `bom` skill for format)
4. Upload gerbers to `https://cart.jlcpcb.com/quote` — configure layers, thickness, color, qty
5. Enable "PCB Assembly", select Economic or Standard
6. Upload BOM and CPL files
7. Review part matching — fix any unmatched parts by searching LCSC numbers
8. Confirm and order

## Tips

- **Prefer Basic parts** — no extra fee, always in stock, faster assembly
- **Check stock before ordering** — extended parts can go out of stock; use the `lcsc` skill to search
- **Panel by JLCPCB** — for small boards, let JLCPCB panelize (cheaper) vs custom panels
- **Lead-free solder** — default is leaded (HASL); select lead-free HASL or ENIG if needed
- **Impedance control** — available for multi-layer boards, specify stackup in order notes
- **Castellated holes** — supported, enable in order options
- **V-cuts and mouse bites** — supported for panel separation
- **Silkscreen minimum** — 0.8mm height, 0.15mm line width for readable text
- **Edge clearance** — keep copper >=0.3mm from board edge (0.5mm recommended)