Did the cold-pressed terminal experience a high-temperature shock during heat treatment?

Phenomena and Causes of High-Temperature Shock
High-temperature shock is mainly manifested as a rapid temperature rise of the terminal body within a short period, leading to a series of physical changes. The main causes and manifestations are as follows:
Typical Process Scenarios: Problems often occur during PCB board assembly processes, such as wave soldering and reflow soldering. In wave soldering, preheating temperatures can reach above 100°C, and the wave peak temperatures can even reach 280°C momentarily; in the reflow soldering preheating zone, peak temperatures may also exceed 230°C.
Direct Manifestations: Sudden high temperatures can cause the plastic insulation parts of the terminal to melt, warp, bubble, or deform, and the metal parts may also change properties due to the high heat.

Core Risks Brought by High-Temperature Shock
High-temperature shock not only affects the terminals themselves, but can also trigger a series of reliability and safety issues:
Increased Contact Resistance Leading to Overheating Cycles: High temperatures can cause oxidation on the contact surfaces of terminals and conductors, forming thin oxide layers. This can significantly increase contact resistance, and the increased resistance generates further heat, forming a vicious cycle, which in severe cases may even result in fire.
Reduced Mechanical Strength: High temperatures can anneal elastic elements inside the terminal, causing them to lose elasticity and reducing contact pressure, leading to loose connections. At the same time, the insulation layer of wires can age and become brittle under high temperatures, reducing insulation performance.
Impact on Current Carrying Capacity: If the crimping area is improperly designed or processed (e.g., incorrect compression ratio), its cross-sectional area may shrink, leading to insufficient current carrying capacity and making it easier to generate heat when current flows.

How to Respond to and Resolve High-Temperature Shock
Optimize Material Selection: Choose metals with higher temperature resistance (such as high-conductivity copper) and resin materials.
Improve Crimping Process: Strictly control the crimping ratio (recommended terminal crimping ratio 65%–75%, conductor crimping ratio 65%–80%).
Precisely Control Heat Treatment Process: Accurately control the temperature and time in the preheating zone, wave zone, and peak zone to avoid unnecessary prolonged high-temperature exposure. Strictly follow the process window to prevent shocks caused by process deviations.
Strengthen Assembly Process Management: Ensure the solder pin is accurately positioned and sized properly; guarantee the solderability of terminals; after assembly, clean thoroughly with no flux residue. Eliminate negative impacts of external factors on terminals.
Adopt Alternative Connection Technologies: For products with particularly high current and strict temperature rise requirements, consider using high-frequency welding and other connection methods. High-frequency welding allows copper to fuse at the molecular level, resulting in lower resistance and better temperature rise control.