In modern electronics manufacturing, PCBA process design is no longer limited to a single assembly technology. Many electronic products today require both SMT (Surface Mount Technology) and DIP (Dual In-line Package / Through-Hole Assembly).
This raises a common and practical question among engineers and buyers:
How are SMT and DIP connected in the PCBA process?
Understanding how these two technologies work together is critical for ensuring product reliability, manufacturability, and cost control.
Understanding SMT and DIP in the PCBA Process
Before discussing integration, it’s important to understand the role of each technology in the PCBA process.
SMT in PCBA Process
SMT is used to mount surface-mount components directly onto the PCB surface. It offers:
High assembly density
Faster production speed
Better suitability for automated mass production
SMT is typically responsible for the majority of electronic components, such as ICs, resistors, capacitors, and fine-pitch devices.
DIP in PCBA Process
DIP (or through-hole assembly) is used for components that:
Require strong mechanical support
Carry high current or voltage
Are exposed to mechanical stress
Examples include connectors, transformers, relays, and large capacitors.
How SMT and DIP Are Integrated in the PCBA Process
In a mixed-technology PCBA process, SMT and DIP are not competing methods — they are complementary. The standard integration flow usually follows this sequence:
1. SMT Assembly Comes First
In most cases, SMT is completed before DIP. The typical steps include:
Solder paste printing
SMT component placement
Reflow soldering
AOI inspection
Completing SMT first minimizes manual handling and protects sensitive surface-mounted components.
2. DIP Assembly Follows SMT
After SMT inspection, the board moves to DIP processing:
Through-hole component insertion (manual or automated)
Wave soldering or selective soldering
This sequence ensures that DIP components do not interfere with SMT placement or reflow profiles.
3. Cleaning and Post-Solder Inspection
Once both SMT and DIP processes are complete:
Flux residues are cleaned if required
Visual inspection and X-ray (if needed) are performed
Defects such as cold solder joints or bridging are corrected
This step is critical to maintaining consistency in the overall PCBA process.
Where Testing Fits Into the SMT + DIP PCBA Process
After SMT and DIP assembly are fully connected, testing becomes the final and most decisive step.
Functional Testing in the PCBA Process
A complete PCBA process should include:
Power-on testing
Signal and interface verification
Functional testing under real operating conditions
Functional testing ensures that SMT and DIP components work together as a complete system, not just as individual soldered parts.
Common Challenges in Mixed PCBA Process
Integrating SMT and DIP is effective, but it also introduces challenges:
Thermal stress differences between reflow and wave soldering
Shadowing effects during wave soldering
Increased process complexity
These risks can be controlled through proper process planning, fixture design, and testing strategy.
Why a Well-Designed PCBA Process Matters
A properly integrated SMT + DIP workflow:
Improves assembly yield
Reduces rework and failure rates
Enhances long-term product reliability
Supports scalable production from prototype to mass manufacturing
This is why choosing a manufacturer with strong PCBA process engineering capability is essential.
Learn More About Professional PCBA Process Solutions
If you are looking for a reliable partner who understands how SMT and DIP are seamlessly integrated into a complete PCBA process — from assembly to functional testing — you can explore professional solutions at: Sanshun Smart
