Laser Power Monitoring (LPM)

Laser Power Monitoring (LPM) is an on-axis monitoring system that continuously measures and documents TARGET and ACTUAL emitted laser output throughout the production process. Thereby, any existing deviations are recorded and displayed relative to each other.

The time-based measurement of the ACTUAL output is converted by means of beam uncoupling in the optical beam path and reflection on a detector unit. The system detects any slow but constant deviations in performance, e.g. due to damage to sensitive optical components or an abrupt drop in output due to a potential failure of a laser diode.

On the one hand, the module can be used as an early warning system for preventing machine downtime with targeted measures when irregularities occur. On the other hand, it makes an important contribution to quality assurance thanks to its process documentation.

Both the TARGET and ACTUAL output are displayed as output over time. It also displays the percentage deviation of both values. The measurement data is immediately available for analysis, and the solution creates a report once the process is complete.

For multilaser machines, each beam path is equipped with its own measuring system. This solution can be upgraded in existing SLM® machines by remodeling the optical bench.

With LPM, a small proportion of the laser radiation is uncoupled in a beam splitter fitted in the optical bench and then guided to the LPM detector unit. A photodiode that is adapted to the wavelength of the laser beam acts as the detector. The detected laser power is sent as an electrical current to a circuit board. On the circuit board, the current is converted to an electrical voltage and compared with the TARGET laser power.

The signals are transmitted to the computer with the user software via a network interface and displayed there in a live mode.