Humping -

High scanning speeds create a swelling with a large contact angle due to the competition between flow inertia (driving metal backward) and surface tension (resisting deformation).

In the context of industrial manufacturing, is a specific surface defect where periodic, bead-like protuberances (humps) form along a weld seam or a 3D-printed track. This occurs when high-speed processes, such as laser powder bed fusion or arc welding, exceed certain velocity and power thresholds. How Humping Develops humping

Humping is primarily driven by fluid dynamics and thermal instabilities within the molten pool: High scanning speeds create a swelling with a

When melt velocity significantly exceeds the welding speed, the weld groove cannot be filled instantly. This causes the melt stream to deflect upwards, initiating a hump. How Humping Develops Humping is primarily driven by

Factors like the recoil pressure of the laser and fast solidification rates can trap these liquid accumulations before they can level out, resulting in the permanent wavy structure. Suppression and Control

Often explained by the Rayleigh instability model , the elongated melt pool behaves like an unstable cylindrical fluid jet, where surface tension causes it to collapse into individual droplets or "humps".

Researchers have developed several features and strategies to prevent or manage humping: