Chicago, Illinois - For over 40 years laser material processing has been defined as: A laser source (continuous or pulsed) providing the ability to deliver large amounts of energy into a localized region of material in order to achieve a desired response such as heating, melting (welding), and or evaporation (cutting and drilling).
During the laser/material interaction a number of unwanted outcomes may occur and these are classified in two categories: primary and secondary. To ensure the quality and consistency of the process it is necessary to optimize both laser and processing parameters in the hope of reducing/eliminating these primary and secondary defects.
Some of the primary defects for laser cutting, drilling and welding, include excessive dross, large kerf width, striations/gouging; excessive recast and oxide layer, cracking, taper; heat affected zone, spatter, porosity, lack of weld penetration, undercut (top and bottom weld bead), heat affected zone cracking, loss of mechanical strength. To some extent, these defects have been historically addressed by optimizing laser and processing parameters, including average and peak power, laser beam size (focusing) and the process speed. Other parameters that are known to be important are gas flow rates, type of assist and shielding gas, orientation of the laser beam to the surface, workpiece geometry, depth of focus, beam mode structure and the joint configuration.
Sometimes optimizing conventional laser and processing parameters has not been enough to produce defect free component processing. In many applications, further optimization is required to produce parts which require no post processing. The combination of advanced control techniques and a better understanding of the nature of defects has resulted in an innovative series of laser processing techniques for fiber laser-based systems. These processing tools are not simply the result of the use of a fiber laser. They are based on and require advanced control of the laser output and tighter integration of the laser, motion, and process sensors to reduce and, in some cases, eliminate secondary defects.
Among the areas addressed are the excessive surface spatter caused by piercing during laser cutting and drilling, “back wall strike” or damage to a surface adjacent to an area of laser hole drilling, and the depression typically found at the end of a weld. These techniques were developed through investigation followed by advancements in integration of laser, motion, and process sensors. They are now helping to increase the productivity and quality in 3D laser material processing.
The presentation will summarize defects historically associated with laser processing and the role of advanced control in reducing or eliminating these defects as a means of improving quality and productivity in precision laser processing.
About the speaker
Mark Barry has spent over 32 years working at Prima Power Laserdyne and is currently Vice President of Sales and Marketing. During this period laser material processing has progressed from the era when slow flow CO2 lasers of 600 Watts were considered state of the art to today’s fast developing and broad spectrum of multi-kilowatt lasers, systems and processes.
A native and current resident of the Buffalo, NY area, Mr. Barry has AS and BS degrees from what is now the State University of New York at Buffalo and has worked in manufacturing and engineering roles for 40 years. His focus has been and remains the pursuit of precision laser material processing.
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