Primes PROFINET - Maximum Power Density

PowerMeasuringModule PMM
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Revision 13 EN - 02/2023
8.2 Maximum power density
To avoid damage to the absorber, the maximum power density at the absorber must not be exceeded. The
permissible power densities vary depending on the beam diameter and the type of absorber installed.
A list of the permitted power densities is given in chapter17 „Technical data“ on page88.
The power density in kW/cm² is calculated according to the formula:
Formula 1: Calculation of the power density
To determine the maximum laser power, the result is weighted with a safety factor of2. The safety factor
compensates the ratio of maximum to average power density of a Gaussian beam (far field). The maximum
laser power in kW depending on the beam radius is calculated according to the formula:
Formula 2: Calculation of the permissible laser power depending on the beam diameter
Example 1: In case of a beam diameter of 1.5 – 3mm, a device with advanced absorber can absorb a maxi-
mum power density of 10kW/cm². For a beam diameter of 3mm (beam radius 0.15cm), the maximum laser
power is calculated as follows:
P in kW = 10kW/cm² · π · 0.15cm · 0.15 cm ·
1
2
= 0.353kW = 353 W
Fig. 8.3: Example calculation 1
Example 2: In case of a beam diameter of >10mm, a device with advanced absorber can absorb a maxi-
mum power density of 4kW/cm². For a beam diameter of 10mm (beam radius 0.5cm), the maximum laser
power is calculated as follows:
P in kW = 4kW/cm² · π · 0.5cm · 0.5 cm ·
1
2
= 1.571kW = 1571 W
Fig. 8.4: Example calculation 2
For quick determination of the maximum laser power as a function of the irradiation time or the
beam diameter, you will find two diagrams in chapter21 „Appendix“ on page95.