In the new copper-aluminum transition clamp copper-aluminum connection, properly setting the crimping process parameters is crucial for ensuring connection reliability. The crimping process uses external forces to induce plastic deformation at the copper-aluminum interface, forming a tightly fitting connection. Deviations in these parameters can lead to poor contact, stress concentration, or material damage, directly impacting the conductivity and mechanical stability of the new copper-aluminum transition clamp. Therefore, clarifying the inherent relationship between various crimping parameters and connection reliability is crucial for process optimization.
Crimping force is the most fundamental parameter in the crimping process and has the most direct impact on copper-aluminum connection reliability. Insufficient crimping force prevents the copper-aluminum interface from fully contacting, leaving tiny gaps between the interfaces. These gaps increase contact resistance, leading to increased localized heating during electrical connection and potentially causing oxidation or ablation over long-term use. Excessive crimping force can exceed the material's plastic tolerance, causing excessive deformation or even cracking of the aluminum component, or brittle damage to the copper component, compromising the structural integrity of the connection and reducing its mechanical strength and conductivity.
The proper crimping sequence also impacts copper-aluminum connection reliability. Copper and aluminum have different plastic properties. Aluminum has greater plasticity but lower strength, while copper has higher strength but relatively less plasticity. If the crimping sequence is incorrect, applying excessive pressure initially to the more rigid copper component may prevent the aluminum component from fully deforming to fit the copper surface during subsequent crimping, resulting in localized loose joints. Conversely, over-crimping the aluminum component first can prematurely induce plastic fatigue, leading to insufficient secondary deformation during the copper crimping phase. This can lead to uneven interface adhesion and reliability risks.
The length of the crimping zone is closely related to connection reliability. If the crimping zone is too short, the copper-aluminum contact area is insufficient, increasing the current density per unit area and susceptibility to interface oxidation due to Joule heating accumulation. Furthermore, the mechanical connection's stress points are too concentrated, making it susceptible to loosening due to vibration or thermal expansion and contraction. If the crimping zone is too long and lacks uniform pressure distribution, it can result in insufficient pressure at both ends and excessive pressure in the middle, causing localized poor interface adhesion and compromising overall connection stability.
The shape and size of the crimping die influence connection reliability by influencing pressure distribution. The mold's contour design must match the structure of the new copper-aluminum transition clamp. Improperly designed mold curvatures or corners can easily cause stress concentration at the contact surface during crimping, leading to localized material deformation, microcracks, or wrinkles. Inadequate matching of the mold dimensions with the new copper-aluminum transition clamp can prevent uniform pressure distribution across the entire contact interface, resulting in a loose crimp in some areas and reduced electrical conductivity and mechanical strength.
Controlling the crimping speed significantly impacts the microstructure of the copper-aluminum connection. Excessive crimping speeds prevent sufficient material deformation and internal stress release, leading to residual stress at the copper-aluminum interface. Overtime, stress relaxation can lead to loosening of the connection. Excessive crimping speeds can cause excessive plastic flow under sustained stress, disrupting the original crystal structure and causing localized material degradation, impacting the connection's conductivity and fatigue resistance.
The dwell time after crimping also indirectly affects connection reliability. An appropriate holding time allows the copper and aluminum materials to fully complete their plastic deformation under pressure, resulting in a tighter interface and reducing gaps caused by elastic rebound. Insufficient holding time can cause material rebound, leading to a drop in contact pressure and the appearance of small gaps at the interface. Excessive holding time can cause material creep under sustained pressure, especially in aluminum parts, which can suffer from excessive creep, leading to a decrease in structural strength and compromising the long-term stability of the connection. The synergistic effect of these parameters determines the reliability of the copper-aluminum connection.
