RoHS-Compliant PCB Assembly

Key Takeaways

• If you sell to the EU, you must ensure that your PCB complies with the latest RoHS (restriction of hazardous substances) directive, which limits these substances in electrical and electronic equipment.

• The directive’s goal is to reduce these hazardous substances' environmental impact and health risks.

• RoHS compliance has a significant impact on PCB design because it requires careful consideration of materials, components, and manufacturing processes.

RoHS-compliant PCB assembly is crucial for electronics sold in the EU market

If you are developing a product for the EU market, it is your responsibility to ensure that you are compliant with the latest RoHS (restriction of hazardous substances) directive (RoHS 3), which limits the presence of these substances in electrical and electronic equipment. These requirements extend to PCB designers and manufacturers, who must be able to demonstrate RoHS-compliant PCB assembly.

The directive’s goal is to reduce these substances' environmental impact and health risks. RoHS 3 has added four new phthalates to the original RoHS list.  All electrical and electronic devices should be compliant with the RoHS 3 directive if the end product will be sold in the EU.

The ROHS directive restricts the use of the following ten hazardous substances in electrical and electronic equipment, including PCBs:

Before products can be sold in the EU, PCB manufacturers, importers, and distributors must comply with RoHS regulations. A PCB assembly can't contain these restricted substances above the allowable limit to be ROHS compliant. In addition, they have to retain proper documentation and traceability to demonstrate compliance.

Impact of RoHS-Compliant PCB Assembly on PCB Design

RoHS compliance has a significant impact on PCB design because it requires careful consideration of materials, components, and manufacturing processes. Here are some key ways in which RoHS compliance affects PCB design:

• Selection of Material: PCB designers must ensure the use of restricted substances does not exceed EU limits. You should use lead-free solder and RoHS-compliant resistors, capacitors, and integrated circuits.

• Thermal Considerations: Traditional lead-based solder has different thermal characteristics than lead-free solder. The PCB designer has to account for these differences to make sure solder joints are strong and thermal performance is efficient.

• Availability of Components: Designers must ensure all components used in PCB assembly are RoHS compliant. Traditionally, lead-based components were commonly used, so alternative parts that meet RoHS requirements might have to be sourced.

• Reliability and Testing: As lead-free solder can be brittle, it can impact the reliability of PCB assemblies. To make sure the final product is reliable, designers need to take this into account.

• Compliance Documentation: To demonstrate compliance with the RoHS directive, designers must keep accurate records and documentation of the materials and components.

• Manufacturing Processes: To accommodate lead-free solder, PCB fabrication and assembly processes must be adjusted. You might need to adjust reflow profiles, refine PCB surface finishes, and fine-tune assembly.

• Supplier Collaboration: All parties must work together to ensure they understand the RoHS requirements and can provide the necessary documentation.

• Environmental Impact: RoHS compliance promotes eco-friendly practices. Other eco-friendly design approaches include reducing the overall size of PCBs to save materials and waste.

Generally, RoHS compliance affects everything from material selection to component availability to manufacturing processes. PCB designers can meet regulatory requirements, reduce environmental impact, and enhance the reliability and performance of final boards by proactively addressing these factors during design.

Cadence’s OrCAD Can Help With ROHS 3 Compliance

Cadence’s OrCAD PCB Designer lets you specify RoHS 3 compliance requirements for any design. Cadence offers a comprehensive set of PCB Design and Analysis Software tools for any application and any level of complexity.

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