PCB Assembly Express provides special pcb assembly procedures to comply with lead free and RoHS pcb assembly standards.

Our Lead Free Assembly Services Include:

  • Lead Free Board Assembly (SMT or THT/PHT)
  • Lead Free Wave Soldering
  • Lead Free Rework
  • Lead Free Printed Circuit Boards Purchased from our PCB fabrication partners

Having a difficult time finding lead free assembly components for your design? Our full service turn-key assembly solution includes helping you research and purchase the needed components.

The Lead Free Assembly Process

The RoHS pcb assembly process requires that the hazardous materials listed in the RoHS Directive are not to be used in the board, components or solder. Bare circuit boards used in the typical ā€œleaded processā€ are typically coated with a lead-tin finish, so the finish on the board must be changed to use a lead-free solder to be compliant with lead-free and RoHS standards.

The lead free solder requires higher temperaturesĀ  (around 30-50 degrees higher) to reach liquidus. All of the components and PCBs must be able to withstand this additional heat. Also, it is important to note that the IC moisture sensitivity level that indicates how long the components can be exposed to the air is approximately 2 classes higher for lead free PCB assembly, so there can be increased moisture sensitivity.

Due to the metallic composition of lead-free solder, the visual appearance will differ significantly from that of a standard leaded solder joint. A good lead free solder joint will give the impression of a leaded cold solder joint, having a dull finish. Our inspection technicians are trained to IPC-610D standards to ensure that the solder joints are solid and of high quality.


Prohibited Substances:

  • Lead (Pb)
  • Mercury (Hg)
  • Cadmium (Cd)
  • Hexavelent Chromium (Cr + 6)
  • Polybrominated biphenyls (PBBs)
  • Polybrominated diphenyl ethers (PBDEs)


Our Lead-Free SMT Assembly Process
  1. Customers can either supply the correct lead free parts or we will procure them for you.
  2. We apply a lead free compatible solder paste alloy (SAC305) using a stencil to the lead free printed circuit board.
  3. All lead free SMT parts are then placed on the board.
  4. The stuffed board is then placed in the oven running a lead free temperature profile to achieve the correct metallic bond between the components and the boards.
  5. Next we install thru hole components and hand solder or wave solder (depending on the number of thru hole components) using a lead free solder alloy.
  6. Each board is visually inspected as a final quality control check
Lead Free Industry Resources

For more information on lead free assembly, please visit these online resources: