What is busbar edge bending?

Extreme Compression and Tension: During bending, the inner side of the narrow edge is subjected to immense compressive forces, making it prone to wrinkling; conversely, the outer side experiences intense tensile forces, placing extremely high demands on the material’s ductility.

Neutral Axis Shift: During the vertical bending process, the material’s neutral axis undergoes a significant shift; this necessitates that the mesin pembengkok busbar be equipped with precise stroke control to prevent a reduction in the cross-sectional area at the bend.

Pronounced Springback: Since the section modulus (resistance to bending) of the narrow face is significantly greater than that of the wide face, the physical springback resulting from vertical bending is far more pronounced—and difficult to predict—than that of flat bending. Consequently, this necessitates that the CNC busbar processing machine system be equipped with high-precision, intelligent springback compensation algorithms.

Lateral Support Technology: Vertical bending dies must be equipped with lateral guide plates. During the bending process, these guide plates act like “walls,” clamping the broad faces of the busbar to prevent the material from bulging laterally under compressive stress, thereby ensuring flatness at the bend.

Catatan: T2 copper busbars possess excellent ductility; however, they undergo significant work hardening during the vertical bending process. This implies that as the bending angle increases, the metal within the deformation zone becomes progressively harder, causing the required bending force to rise exponentially.

Compact Design: Vertical bends allow the busbars to change direction within the switchgear in an “edge-mounted” orientation. This arrangement significantly reduces the horizontal depth occupied by the busbar assembly, enabling the distribution cabinet to be designed with a slimmer, more compact profile.

Flexible Obstacle Avoidance: In complex routing environments—where busbars must navigate around supports, current transformers, or other busbars—vertical bends introduce a vertical dimension, thereby enabling the “lateral maneuvering” required to bypass obstacles—a feat impossible with horizontal bends alone.

Enhanced Heat Dissipation: Vertically oriented busbars typically outperform horizontally laid ones in terms of vertical heat dissipation, thereby helping to mitigate temperature rise during high-current operation.

Enhanced Electrodynamic Strength: When subjected to the massive electromotive forces generated by short-circuit currents, structures formed through vertical bending typically exhibit superior spatial rigidity, rendering them less susceptible to severe displacement or deformation.

Reduced Overlapping Components: Traditional routing methods may require the use of multiple busbar segments and connectors; however, single-pass vertical bending reduces the number of contact points, thereby lowering contact resistance and mitigating potential risks of overheating.

High Consistency: When integrated with CNC control systems, the busbars produced in batches exhibit exceptionally high angular consistency, ensuring uniform aesthetics and ease of installation for the internal wiring across the entire batch of electrical cabinets.

Challenges in Physical Deformation: Internal Wrinkling and External Cracking

Technical Challenge: During vertical bending, the inner side of the busbar’s narrow edge is subjected to immense compressive forces, which can easily result in wrinkling or bulging (resembling a “wavy” pattern). Conversely, the outer side experiences intense tensile forces; if the material lacks sufficient ductility or the bending radius is too small, micro-cracks may form along the edge, potentially leading to fracture.

Solution:

Dedicated Limiting Die: Employs a punch-and-die design featuring lateral supports; during the bending process, the die’s side walls forcibly “compress” the material, preventing the inner metal from bulging outward and ensuring uniform thickness at the bend.

Controlling the Bending Radius (R-value): Adjust the R-value based on the busbar thickness. Typically, the minimum bending radius for vertical bends should be greater than that for horizontal bends, in order to mitigate tensile stress at the outer edge.

The Influence of Bending Radius R and Springback Compensation on Busbar Bending Accuracy

Material Preheating (for Thick Plates): For extremely thick copper busbars—although CNC busbar machines typically perform cold bending—ensuring the material is at room temperature (rather than in an extremely cold environment) helps enhance its ductility.

The rebound is significant and difficult to predict

Technical Challenge: Since vertical bending targets the narrow edge of the material, the section modulus against bending is relatively large; consequently, the springback angle is significantly more pronounced—and less stable—than in horizontal bending. Even minute variations in material hardness within the same batch can result in angular deviations in the finished product.

Solution:

CNC Springback Compensation System: Modern CNC busbar machines monitor real-time position using displacement sensors. The system features a built-in database that automatically adds a “compensation angle” to the target angle, based on the busbar’s width, thickness, and material.

The Influence of Busbar Width-to-Thickness Ratio on Bending

Secondary Angle Verification: Certain high-end machines feature a “bend-measure-correct” function. This process involves first performing an initial bend; sensors then measure the resulting angle, and the hydraulic system subsequently compensates for any discrepancy, thereby ensuring an angular accuracy within ±0.3°.

Cross-Sectional Distortion and Effective Contact Area

Technical Challenge: During the vertical bending process, the rectangular cross-section of the busbar is prone to “trapezoidal distortion”—specifically, a slight variation in width occurs at the bend. This directly results in uneven contact surfaces between the busbar and other components during switchgear assembly, thereby increasing contact resistance and leading to overheating during operation.

Solution:

Pressure Equalization Technology: Through the precise control of the hydraulic system, this technology ensures the stable application of pressure during the bending process, thereby minimizing material distortion caused by instantaneous impact.

Post-processing: In cases involving extremely stringent process requirements, a slight flattening operation may be performed following the vertical bending stage to ensure the flatness of the connection areas.