fiber laser final - laser optics - ophir laser measurement · laser being tested was a 1070nm fiber...

Ophir Photonics Group 3050 North 300 West

North Logan, UT 84341 Tel: 435-‐753-‐3729

www.ophiropt.com/photonics

Beam Profiling of 1 KW Fiber Laser with Camera-Based Profiling System By John McCauley, Midwest Regional Sales Manager, Ophir Photonics Group, [email protected] Laser beams are like light bulbs, they change in output over time. When laser manufacturing high precision, high reliability parts, this presents a challenge. Because of this, there is a need to regularly measure and manage the characteristics that determine a beam’s quality and consistency. There are several steps involved in maintaining a laser’s efficiency over time. This maintenance is important to help prevent laser output variation from affecting the end product being manufactured. Measuring Laser Beams One of the first steps to decrease these adverse effects is beam measurement. To ensure that the process remains consistent, key laser parameters such as laser power or energy, beam size, and spatial distribution, must remain unchanged. As a laser ages, the changes in these data points can indicate degradation of the system’s components. Data from the laser needs to be collected and analyzed, either by visual inspection or with laser measurement equipment, such as cameras, meters, and beam analysis software. Testing a Beam Profile An Ophir customer wanted to monitor the performance of their laser over time. They had a 1 kW fiber laser that was being used to repair airplane engine components through a direct metal deposition process. This process allows a focused laser beam to adhere metal powder to a damaged metal piece. The customer was expecting the test would show a Gaussian profile for the laser beam, but it was discovered that they were actually getting a flat top profile. Such a change can mean the difference between a precision cut provided by a Gaussian profile laser beam versus a beam that provides less penetration, but a faster means of adding metal powder.




A typical laser measurement setup includes a laser source, lenses to dissipate the beam, meters to measure the laser’s power and energy, and an imaging device interfaced with beam profiling software to see the actual form of the beam, also known as the beam profile. In this case, the laser being tested was a 1070nm fiber laser source with 600µm fiber, CW, 1 KW maximum average power; a Spiricon SP620U silicon CCD camera; and BeamGage® Professional laser profiling software. The laser’s performance was measured at 350W, 500W and 750W, as shown in the diagram. During the test of this relatively new and stable laser, it was observed that differences in power levels resulted in only slightly different energy distribution across the focused spot. However different power levels resulted in different spot sizes. Controlling Process Variables When working with a process like direct metal deposition, or any other laser sintering processes, preparation and setup time is of the essence as the costly parts being built take a relatively long time to finish. In this case, the manufacturer put a regular, periodic beam measurement program in place to assure them the laser’s performance remains consistent over time. (Depending on the demands of the process, the program can be run quarterly, monthly, weekly, or on a shift-by-shift basis.) With this program, they now know that many of the variables that lasers can introduce to the process are being monitored and addressed, as needed. For more information BeamGage® Beam Profiling Software Spiricon SP620U Camera LBS-300-NIR Beam Splitter Ophir Photonics Group http://www.ophiropt.com/photonics




Beam Profiles from 1 KW Fiber Laser

Figure 1a. Profile at 350W (no Z-scale adjustment) Figure 1b. Profile at 350W (with Z-scale adjustment)



fiber laser final - laser optics - ophir laser measurement · laser being tested was a 1070nm fiber...

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