Metal additive manufacturing is the process of joining materials to make objects from 3D computer-aided design (CAD) model data.Laser powder bed fusion (PBF) is one such process, in which thermal energy derived from a laser beam selectively fuses regions of a powder bed.A team from Heriot-Watt University, Edinburgh, and the University of Birmingham in the UK used high-speed imaging to investigate the interaction of the laser beam with the powder bed at sub-atmospheric pressures.They used a SOLA SM Light Engine® to illuminate a circle of ~10 mm diameter on a stainless steel powder bed inside a vacuum chamber.Image sequences were recorded at 40,000 frames per second by a monochrome camera.The data obtained indicate that operating in a soft vacuum (>50 mbar) would provide the simplest implementation of PBF at sub-atmospheric pressures.The reduction in vaporization temperature at reduced pressure means that the same penetration depth can be achieved at lower laser powers, resulting in a stabilizing effect on the process.
High-speed images at 20mbar. Laser power and scan speeds of (a) 50W and 0.2m/s, (b) 100W and 0.4m/s and (c) 200W and 0.8m/s.
Lumencor, Inc. has been named 2020 Product Innovation of the Year honoree by the Portland Business Journal for our next generation SOLA light engine®. Each year, the PBJ honors the region’s top manufacturing companies who drive the economy with innovation, excellence and productivity. The new generation SOLA features increased power, longevity, stability and robustness over the projected 15 year life time with no replacement parts. Lumencor’s SOLA light engine is used in fluorescence microscopy for life science and materials science applications… Read Press Release
Characterization of Superhydrophobic Surface Coatings
When two or more water droplets coalesce on a superhydrophobic surface, the resulting droplet can jump away from the surface due to inertial−capillary energy conversion. The resulting passive shedding of micro-scale water droplets has the potential to enhance heat transfer, anti-icing, and self-cleaning properties. To study this process, researchers at the University of Illinois developed an improved imaging technique called focal plane shift imaging (FPSI) to measure three-dimensional (3D) droplet trajectories. A high-speed camera is used to obtain video recordings at variable frame rates up to 500,000 frames per second. Illumination is supplied by aSOLA SM light engine®, specifically chosen for its high-intensity, low-power consumption and narrow spectral range (380−680 nm) in order to minimize heat generation at the surface due to light absorption. The effects of initial droplet size mismatch and multiple droplet coalescence on the jumping droplet velocity are revealed, showing that multi-droplet jumping has the potential to enhance the droplet departure speed.
SPECTRA Light Engine® Takes the Win Highlighting smFISH
In celebration of Earth Day Lumencor launched its annual Light Microscopy Imaging Competition to highlight Lumencor’s commitment to manufacturing bright, clean, and mercury-free light engines. The tallies are in and we are happy to announce the winners. As always, we are impressed with the breadth and skill it took to capture each of the images submitted in this years competition. For more information on how Lumencor light engines can help you in your research, please contact us.
1st Place – George McNamara and Lauren Blake
Johns Hopkins School of Medicine, Baltimore, MD Light Engine:SPECTRA light engine®
5-plex mouse embryonic fibroblasts expressing MS2-tagged beta-actin mRNA. Red Halo-JF549-NLS-MCP, Green Atto594 POLR2A mRNA FISH, Blue DAPI, Cyan Cy5 beta- actin-MS2 mRNA FISH, Magenta Alexa Fluor 488-anti-DDX6 immunofluorescence. Microscope details at http://confocal.jhu.edu/ current-equipment/fishscope. Specimen preparation by Lauren Blake, Prof. Bin Wu’s lab (JHU Biophysics). Imaging by George McNamara, Ross Fluorescence Imaging Center.
A nostoc discovered in Antarctica autofluorescing under TRITC excitation. This nostoc was found inside a microbial mat in the Dry Valleys of Antarctica. A nostoc is a genus of cyanobacteria with beaded filaments intricately woven inside a gelatinous pouch. This image highlights the structure of the beaded filaments and their scaffolding within the gelatinous pouch.
Cos-7 cells spread on a tension gauge tether (TGT) surface and imaged on a Nikon Ti2 eclipse microscope using a Lumencor light engine and a turret wheel with different excitation and emission filter cubes – The RICM image (panel 1) was taken by removing the emission filter from the path. Cell tension indicated by TGT probe opening (panel 2) and paxillin staining (panel 3).
Control latency limits the response time of all USB-connected microscope accessories, including cameras, stage controllers, filter wheels, and Lumencor light engines. Latency originates from the fact that the supervising PC operating system (usually Microsoft Windows) must allocate time to many competing tasks. As shown in the adjacent data plots, the impact on the user is that the duration of light output on the specimen is longer, and sometimes much longer, than the exposure time set in the acquisition software.
Duration of light output produced by a CELESTA light engine®, and detected by an external analog photodiode, in response to various exposure times set for a Hamamatsu ORCAFlash 4.0 camera controlled by MicroManager (v1.4.23) image acquisition software. Note that the discrepancies between set exposure time and light output duration are not speciﬁc (except in minor details) to any particular image acquisition software or light engine or camera model. Panel A shows data for light engine control via LEGACY mode USB communication. Panel B shows the same nominal exposure sequence controlled via STANDARD mode USB communication.
Two scenarios are shown, one using LEGACY mode USB communication (as implemented on the SPECTRA X and SOLA SE light engines), and the other using STANDARD mode communication (as implemented on the AURA III, SPECTRA III and CELESTA light engines). Because the USB data transmission rate in STANDARD mode is faster than that of LEGACY mode (115,200 vs 9,600 baud), it provides a signiﬁcant reduction of latency for exposure times on the order of 100 ms (and above). However at short exposure times (5–10 ms), the impact of the faster communication speed in STANDARD mode diminishes, as the response is dominated by the software processing speed.
To obtain light output durations less than about 50 ms, timing must be derived from a hardware controller instead of the PC operating system. The hardware controller supplies TTL timing signals to the light engine via a breakout cable (Table 1). Examples of millisecond-duration light pulses generated in this way can be found in the Performance section of our website. At the present time, the capacity to acquire time-lapse sequences of short duration exposures is limited by the camera (modern sCMOS cameras typically have a maximum frame rate of around 100/second), rather than by the light source.