Process Gas Flow Dynamics
Process gas flow dynamics describes how the shielding gas flows over the powder bed and what effects this has on weld quality. A laminar flow helps to carry away fumes and condensates and stabilize the laser beam.
Physicochemical mechanism of action
The process gas flow dynamics refers to the movement of the shielding gas over the powder bed during laser welding. A laminar airflow flows in parallel layers and prevents turbulent flows that could disturb the laser beam. This flow also carries away fume and condensate, which improves weld quality.
Metallurgical relevance & welding risks
Insufficient or turbulent process gas flow can cause fume to not be effectively removed and condensate to form in the laser beam. This can lead to quality issues such as lack of fusion or irregular weld profiles. A laminar flow prevents these problems and ensures a homogeneous weld zone.
Shop practice & action guidelines
To ensure optimal process gas flow dynamics, the shielding gas should flow over the powder bed at a rate of 20 to 30 m/s. This can be achieved by adjusting the gas flow meters. A laminar flow is ensured by uniform gas density and constant flow. If needed, additional fans or nozzles can be used to regulate the flow.