Energy Density in Powder Bed
Energy density in the powder bed is the ratio between laser power, scan speed, layer thickness, and hatch spacing. It determines the thermal input into the material and controls the fusion of the layers.
Physico-chemical mechanism of action
The energy density in the powder bed is calculated by dividing the laser power by the product of scan speed, layer thickness, and hatch spacing. This value indicates how much energy is introduced into the material per unit area.
Metallurgical relevance & risks during welding
An excessively high energy density can lead to strong melting and to a fine grain structure. This increases the toughness of the material but also increases the risk of hot cracks and distortion. An excessively low energy density prevents adequate melting and can lead to incomplete fusion or to a fine grain structure.
Workshop practice & instructions
To achieve the optimum energy density, the following values should be maintained: laser power between 100 and 300 watts, scan speed of 2 to 5 mm/s, layer thickness of 0.05 to 0.1 mm, and hatch spacing of 0.2 to 0.4 mm. The exact setting depends on the specific material and desired result quality.