Color Change Of Insulating Sleeve Caused By Improper Cold Pressing Needle

crimp socket contact If the crimping is not done properly, it can lead to uneven stress inside the joint, stress concentration on the metal surface, and uneven heating of the insulating sleeve. These crimping defects will manifest as noticeable color changes on the insulating sleeve over prolonged equipment operation.

This discoloration is not due to spontaneous material aging, but rather the result of long-term crimping deformation, localized temperature rise, and microscopic electrochemical reactions. When the interfacial stress between the metal and insulation material in the crimped area is inappropriate, the temperature fluctuations in that area are greater. Combined with the influence of humidity and oxygen in the air, this accelerates material degradation, resulting in a color change.

When the female crimp contact cable does not fit tightly with the cable components, the insulation layer suffers not only mechanical deformation, but also heat accumulation due to changes in contact resistance. This heat accumulation, after hundreds to thousands of hours of operation, will leave discoloration marks on the radial insulating sleeve. The discoloration location often coincides with the stress concentration point of the crimping, creating a significant contrast with the color of the normal male crimp contact crimped area.