with ultra-pure super-polished suspended mirrors coated with forty quarter-wave layers to have reflectivity better than five 9’s. Servo-controlled ground isolations systems stabilize, attenuate and filter out ground motion with input from seismometers, so the laser light that makes about 140 bounces per second is sensitive enough to be considered a transducer for gravitational waves at the output of the interferometer.
All LIGO science data is publicly available on the center’s open website, and since it came online, a total of three events have been observed that are bringing new information – that black holes in binary systems exist. Two identical signals were seen simultaneously by systems in two locations in eastern Washington State and near Baton Rouge in Louisiana. After correcting for differences in orientation and background noise and removing the few-second offset between the locations, it was determined that the gravitational wave signal seen here on Earth corresponded to events that occurred 1.4 billion years ago between two black holes of 29 and 36 solar masses respectively. Signals show how they behave when they interact and provide an estimate of where the event was located in the universe.
Laser Materials Processing (LMP) Conference Technical Highlights The LMP Conference, chaired by Christoph
Leyens from
Fraunhofer IWS, brought together laser, manufacturing and materials science disciplines and presented talks on laser drilling, cladding, cutting, welding, additive manufacturing/3D printing and materials for lightweight construction.
A highlight of the lightweight construction talks was about carbon fiber reinforced plastics (CFRP), which are used in many industrial sectors. Sven Bluemel from Laser Zentrum in Germany presented information that will help optimize laser cutting processes in his talk Time Resolved Analysis of Nanosecond Pulsed Laser Processing of CFRP (LMP8-803). Bluemel synchronized a CMOS camera and strobe light with a fiber guided nanosecond pulsed laser to analyze the plasma plume during laser cutting of 3D CFRP parts with different processing parameters. Analysis of pictures of the
cutting
process and resulting plume showed how the plume varied with pulse energies and changed during processing so ablation thresholds and process boundaries could be set.
Ti6AL4V is the major industrial alloy used in aerospace, medical implants, automotive fuel nozzles and many other applications, and many talks and posters mentioned 3D printed devices using its power feedstock. Dirk Herzog from Hamburg University of Technology, Germany, spoke about how different powder feedstocks affect the quality of parts produced by laser melting or laser fusion in his talk Relationship Between Powder Characteristics and Part Properties in Laser Beam Melting of Ti6AL4V and Implications on Quality (LAM1-705). His work characterized the three forms of Ti6AL4V powders IGA, PA
and ICP, from several manufacturing sources by SEM, particle size distribution, chemical composition and flowability from five different methods that test static and dynamic states. He created laser beam melted parts and measured properties such as density, static strength, yield strength, ultimate tensile strength, elongation and Vickers hardness. He found that all three powders produced dense specimens and can be used, and he presented the differences between them and made recommendations.
Laser Microprocessing (LMF) Conference Technical Highlights “2016 was another great year for the Microprocessing Conference,” said LMF Conference Chair Michelle Stock, from mlstock consulting. “We heard about applications as diverse as wearable electronics and writing skin by 3D printing cells with ultrafast lasers. We gained more insight into how to improve processing speed and precision with new beam delivery and beam shaping techniques.”
A highlight in the smart and wearable gadget area was Alan Conneeley’s invited talk Laser Micromachining of Contactless RF Antenna Modules for Payment Cards and Wearable Objects (LMF5-M501) involving work at the National University of Ireland in Galway. Conneely presented several successful applications of laser ablation for next generation contactless payment cards and flexible wearable devices. Antennas were formed from copper laminated epoxy tape on plastic and flexible substrates as well as on copper PCBs. Laser processing allowed much smaller resolution antenna features to be designed and fabricated compared to chemically etching copper. New antenna designs using this process have a higher density of turns in a given area enabling contactless cards and payment systems to meet design goals for Europay, MasterCard and Visa (EMV) industry standards.
Two talks on how lasers interact with transparent materials were another conference highlight. Thomas Hermann from Photonik-Zentrum Kaiserlautern, Germany spoke about a new laser technique to modify the surface of bulk glass in his talk Selective Glass Surface Modification with Picosecond Laser Pulses for Spatially Resolved Gloss Reduction (LMF4-M402). Specular gloss, sheen and haze are important in devices such as automotive headlamps and mobile screens. His work investigated how the surfaces change with single, double and more than two pulses per location, pulse energy, line distance and the influence of substructures. He demonstrated that glass with dramatic gloss reduction by direct laser structuring still had high transmission, and the process uses no chemicals, no masking, is fast and flexible, and leaves sharper features on the surface compared to chemical etching.
In another transparent material talk, Geoffrey Lott from Electro Scientific Industries in Portland, Oregon, covered Enhanced
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