Define the project
Connectors, transformers, relays and other leaded components may require through-hole assembly alongside SMT. Hole geometry, component orientation, mechanical support and soldering access affect the process route. Specify the parts that must withstand mechanical loads or special operating conditions.
Requirements to include
- Assembly drawing and polarity information
- Hole and lead dimensions
- Temperature-sensitive components
- Mechanical fastening and connector alignment
- Soldering, cleaning and inspection requirements
Decisions to resolve before release
Review the assembly sequence for mixed-technology boards. Nearby SMT components, tall parts and access restrictions can change how through-hole joints are produced and inspected. Include any limits on soldering temperature or time from the component documentation.
Request a project-specific quote
Send the design revision, quantity and required date with the technical requirements above. Identify anything still under review. Feasibility, process details, inspection scope and delivery are confirmed against the actual files; a general service description is not a production approval.
THT and mixed assembly are process choices
Through-hole technology uses component leads or terminals inserted into board holes. Mixed PCB assembly combines through-hole and surface-mount components on the same product. Select the soldering sequence around component limits, access and the already-assembled features.
Wave, selective and manual soldering have different fixture, clearance and thermal requirements. Confirm which approach is proposed for each component group. A through-hole package is not automatically more reliable than an SMT alternative; the mechanical support and qualified joint matter to the product.
Review fit and retention before soldering
Check maximum lead dimensions against minimum finished holes, including lead length, board thickness and seating height. Define any permitted lead forming or trimming and preserve clearance to the enclosure. Heavy connectors or components may need separate mechanical support.
Specify workmanship requirements and the inspection or test evidence expected after soldering. In a mixed build, assess the thermal exposure of previously assembled parts and access for cleaning or coating where required. Submit connector drawings and special handling notes with the assembly package.