Volumetric Energy Density
The volumetric energy density parameter measures thermal energy per unit volume in laser welding, accounting for laser power, scan speed, layer thickness, and hatch spacing. It helps prevent porosity.
Physical-Chemical Mechanism
The volumetric energy density parameter calculates the thermal energy input into the material by multiplying laser power by time while welding a layer. This value is then divided by the volume of the welded layer.
Metallurgical Relevance & Welding Risks
Too high a volumetric energy density can lead to overheating and local distortion, which in turn causes porosity and lack of toughness in the material. Too low a value results in insufficient heating and poor weld quality.
Shop Practice & How to Do It
To set the volumetric energy density correctly, first determine the desired layer thickness. Then choose appropriate laser power and scan speed. The hatch spacing should be set to distribute thermal energy evenly. A typical range for this parameter is 0.5 to 1.5 J/cm³. Check with a pyrometer if the weld is heated properly.