MKS unveils noncontact laser beam monitoring system for additive manufacturing

MKS Instruments unveiled what it says is the industry’s first noncontact laser-beam monitoring system intended for additive manufacturing.

At this year’s SPIE Photonics West (San Francisco, CA; Jan. 27 to Feb. 1, 2018), MKS Instruments (Andover, MA) unveiled the Ophir (North Logan, UT) BeamWatch AM, which the company says is the industry’s first noncontact laser-beam monitoring system intended for additive manufacturing. The BeamWatch AM uses Rayleigh scatter to image the beam without contacting the laser. It is one of the new generation of Ophir beam measurement devices that operate this way—the original BeamWatch, introduced in 2014, measures beams with powers from 1 to 100 kW. The new BeamWatch AM measures beams from 30 to 1000 kW, showing Ophir’s confidence in the ability of Rayleigh scattering measurements to characterize lower-power beams.

The instrument measures 176 × 177 × 126 mm and is designed for real-time measurement of focal shift during laser startup of powder-bed fusion manufacturing processes. It measures key beam size, position, and quality parameters, including focus spot size and beam caustic, for additive manufacturing processes such as selective laser sintering (SLS) and selective laser melting (SLM). These measurements allow users to more easily determine when the beam is aligned and in focus, providing more consistent metallurgy, avoiding structural weakness, captured stress, and voids, according to Ophir. Measurements can be displayed as tabular, 2D, and 3D views.

Ophir says that using Rayleigh scatter to image the beam without contacting the laser removes the potential for damage to the laser and speeds the measurement process by up to two minutes. BeamWatch AM measures laser powers to 1000 W in situ at rates up to 14 Hz, and can handle up to 120,000 J without cooling. System measurements include laser power, waist width, waist location, focal plane location, spot size at focus, spot size at any point along the 10 mm measurement space, ellipticity, Rayleigh length, M2, K, BPP, divergence, and centroid beam tilt. Results can be charted and exported to .csv files for importing into Excel or other analysis software. The BeamWatch AM data sheet can be found at http://bit.ly/2hIa5Ez.

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