Board & LED review
Confirm substrate (Al MCPCB vs FR-4), LED package type and any silicone lens constraints.
PCB assembly
LED PCB Assembly
LED modules fail when polarity is reversed, thermal pads are starved of solder, or MCPCB heat paths are ignored. XFPCB assembles LED PCBs with placement rules and reflow plans tuned for arrays and power LEDs.
LED Assembly Differs from Generic SMT
LED boards often use aluminum metal-core PCBs, tight polarity marks and large thermal pads under high-power packages. Paste volume and reflow must wet the thermal pad without tombstoning small nearby parts.
Share LED binning or Vf grouping needs if you require matched strings - those rules belong in the traveler.
LED Assembly Steps
Stencil for thermal pads
Design apertures so thermal pads get enough paste without bridging.
Polarity-controlled placement
LED cathode/anode marks verified against CPL before the full array runs.
Reflow & inspect
Profile for MCPCB thermal mass; inspect polarity, tombstones and solder on thermal pads.
LED-Specific Controls
- MCPCB boards sink heat - reflow profiles differ from thin FR-4.
- Never skip polarity verification on diode/LED arrays.
- Lens or silicone-dome LEDs may need lower peak or special handling - send datasheets.
- Conformal coat or potting, if required, is quoted as a separate step after optical check.
LED Quotation Focus
| Project Area | XFPCB Guidance |
|---|---|
| Substrates | Aluminum MCPCB, copper-base, or FR-4 LED boards |
| Critical SMT risk | Thermal pad voiding / polarity reverse |
| Often paired with | LED PCB fabrication and stencil service |
| Optional test | Simple power-on or string continuity if specified |
LED DFM Checklist
Thermal Pad Apertures
Paste windows are sized so heat-slug pads wet without starving or bridging.
Polarity Marks
Silkscreen and CPL must agree; we stop on mismatch rather than guess.
MCPCB Profile
Aluminum boards get a profile that accounts for higher thermal mass.
Useful Terms
- MCPCB
- Metal-core PCB, often aluminum for LED thermal paths.
- Thermal pad
- Large grounded pad under power LED packages.
- Binning
- Grouping LEDs by color/Vf for matched appearance.
- Array
- Multiple LEDs placed in a pattern on one board.
Related XFPCB Pages
LED PCB Assembly FAQs
Can XFPCB assemble aluminum LED PCBs?
Yes. MCPCB assembly is common for lighting. Share board thickness and LED datasheets so reflow and handling are set correctly.
How do you prevent reversed LEDs?
Polarity marks on silkscreen plus CPL verification and AOI/visual checks on the array.
Do you match LED bins?
If you require binning, state the rule and supply pre-binned parts or clear purchasing specs.
What files help an LED quote?
Gerbers, BOM with LED MPNs, CPL, and notes on thermal pad paste or test requirements.
Request an LED PCB Assembly Quote
Tell us substrate type, LED package and any binning or power-on test needs.
- Specify MCPCB vs FR-4 and board thickness.
- Include LED MPNs and polarity drawing.
- Note conformal coat, potting or optical test if required.