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1 PRIZE
st

SCANFIELDMONITOR (SFM)

> Stefan Wolf, Head of Research & Development
PRIMES GmbH
Pfungstadt

The novel and patented measurement principle utilized in the PRIMES ScanFieldMonitor (SFM) The measurement of a single vector is done within the range of milliseconds. This enables a high
enables the measurement of laser beam parameters during the movement of a scanned vector. The repetition rate without considerable effort, ideal for time-dependent measurements such as laser-
resulting laser-scanner-characterization provides all geometrical and laser related parameters induced thermal focus shift within an optical setup. The photodiode together with the high frequent
relevant for remote applications. Additionally, beam position and movement of the laser-scanner- analogue digital converter are helping to solve timing problems. Figure 1 and 2 show exemplary
unit in its scanning field are determined in the same operation. the process quality improvements using SFM. Each laser source has a power dependent switching-
on and -off behavior. Assuming that the scanner used has originally been aligned at low power,
The measurement principle is based on a defined scattering structure engraved by an ultra-short timing errors will occur at process power. Figure 1 shows the process result of a system that
pulse laser into a transparent material. When the laser beam passes over this structure, the light has been aligned at a different power level. Figure 2 shows the improvement after a single SFM
is scattered by means of the engraved stray elements. The characteristic SFM scattering signal is measurement iteration.
detected by a photodiode. It allows the calculation of the vector location within the scan field, vector
start and end point as well as the scanning speed. Besides all these parameters the beam diameter
is calculated based on the generated 1D integrated signal at the same time. Without any further
optics included, the SFM provides a wide incidence angle of ± 20° to enable measurements on the
entire scan field. Among other things, this also allows the stitching of overlapping scanner areas
with an accuracy of less than 10 µm.

SFM development was motivated by a variety of new applications in additive manufacturing
and e-mobility using laser and scanner as key enabler for fast and high reliable processes. A
significant percentage of these applications come along with strict safety requirements, which we
aim to facilitate. The rapid measurement procedure of the SFM is intended to reduce the hurdles
of calibration, qualification and documentation, shall minimize down time, increase machine
availability and ultimately lower costs. The SFM is a perfect tool to check the reproducibility of
process relevant parameters at various locations all over the world.
> Laser delay causes processing error > Undisturbed marking using corrected delay
(figure 1) (figure 2)

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