A PCB solder terminal must not be converted to solder-free use merely because it feels tight in a hole. THT soldering and press-fit are different joining designs. Confirm authorization in the applicable terminal and PCB specifications rather than increasing force to replace the intended solder joint.
Identify the joining mechanism
Würth Elektronik describes a designed press-fit pin forming an electrical connection in a plated through hole. Phoenix Contact describes through-hole reflow as a solder-paste and reflow process. These principles do not establish that an arbitrary solder pin is a press-fit product.
| Check | Through-hole soldering | Designed press-fit |
|---|---|---|
| Joint formation | Specified solder joint | Designed pressed contact |
| Pin | Soldering fit and solderability | Specified press-fit contact zone |
| PCB | Finished hole, land and soldering conditions | Manufacturer's hole and board requirements |
| Records | Applicable soldering inspection | Applicable insertion inspection |
Specify the finished hole
Request pin contact-zone geometry, tolerances, finished plated-hole requirements, board thickness and relevant hole-wall conditions. Drill diameter and finished plated-hole diameter refer to different manufacturing stages. Do not infer a hole from a photograph or reuse another family's recommendation.
Changes to the pin, board or hole process require an engineering review of validation needs. The same nominal hole number alone does not demonstrate compatibility.
Stop abnormal insertion
Retain the part and board IDs if resistance, tilt or board bending is abnormal. Check dimensions, burrs and orientation. Hammering, forced insertion and unapproved filing are not default corrective actions. Even a dedicated press-fit design requires its approved equipment, support, stroke and inspection method.
A project may record insertion force in N against displacement in mm, but the acceptable curve, acquisition method and limits must match the qualified design. Immediate continuity alone establishes neither hole-wall condition nor long-term contact performance.
Make the purchasing requirement explicit
For PCB solder terminals, state the intended soldering process. If solder-free insertion is needed, request a separately confirmed controlled solution. This page claims no unverified Hongchuan press-fit model or available M3/M4/M6 SKU.
The terminal hole and land review addresses soldering geometry; it is not press-fit approval.
Questions
Does tight fit plus continuity permit omitting solder? Follow the designed joining method and acceptance requirements.
Does a smaller hole create a press-fit design? Pin, hole and assembly process must together meet the confirmed specification.
References
Würth Elektronik press-fit principle; Phoenix Contact PCB assembly.
The cover is an AI joining-principle illustration, not a Hongchuan section, interchangeable model or insertion record. Geometry is not a manufacturing specification.