scholarly journals Seam Formation in Laser Beam Micro-Welding with Spatial Power Modulation

2021 ◽  
Vol 8 (1) ◽  
pp. 60-72
Author(s):  
Mirko Aden ◽  
Paul Heinen ◽  
Alexander Olowinsky
Keyword(s):  
Laser Beam ◽  
Cross Sections ◽  
Feed Rate ◽  
High Frequency ◽  
Power Modulation ◽  
Oscillatory Movement ◽  
Laser Sources ◽  
Thermal Simulations

AbstractWhen laser sources of high brilliance are used for the micro-welding of metals, small seam dimensions are generated. If the spatial power is modulated by a superposition of the linear feed rate and a circular-oscillatory movement of high frequency, the width of the seam is controlled by the amplitude of the circular movement. In this study, the irradiation pattern of the seam was calculated and reveals that some spots of the seam area are not irradiated, while other have been irradiated several times. The seam shapes were visualized with micro cross-sections for different laser powers, linear feed rates and oscillatory amplitudes. Thermal simulations were made to discuss the different seam shapes. A consequence of the oscillatory movement is the appearance of different solidification fronts, which are visible in the micro cross-sections.

scholarly journals Heterodyne Standing-Wave Interferometer with Improved Phase Stability

2021 ◽  
Author(s):  
Ingo Ortlepp ◽  
Jens-Peter Zöllner ◽  
Ivo W. Rangelow ◽  
Eberhard Manske
Keyword(s):  
Laser Beam ◽  
Frequency Shift ◽  
Standing Wave ◽  
Phase Difference ◽  
Phase Stability ◽  
Constant Velocity ◽  
Optical Axis ◽  
Fixed Position ◽  
Length Measurements ◽  
Laser Sources

AbstractThis paper describes a standing-wave interferometer with two laser sources of different wavelengths, diametrically opposed and emitting towards each other. The resulting standing wave has an intensity profile which is moving with a constant velocity, and is directly detected inside the laser beam by two thin and transparent photo sensors. The first sensor is at a fixed position, serving as a phase reference for the second one which is moved along the optical axis, resulting in a frequency shift, proportional to the velocity. The phase difference between both sensors is evaluated for the purpose of interferometric length measurements.

Enhanced Vibration Control of Ultrasonic Tooling Using Finite Element Analysis

1991 ◽  
Author(s):  
Kevin O’Shea
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cross Sections ◽  
High Frequency ◽  
Excellent Correlation ◽  
Accurate Identification ◽  
Element Analysis ◽  
Optimum Configuration ◽  
Slot Length ◽  
Design Variables

Abstract The use of finite element analysis (FEA) in high frequency (20–40 kHz), high power ultrasonics to date has been limited. Of paramount importance to the performance of ultrasonic tooling (horns) is the accurate identification of pertinent modeshapes and frequencies. Ideally, the ultrasonic horn will vibrate in a purely axial mode with a uniform amplitude of vibration. However, spurious resonances can couple with this fundamental resonance and alter the axial vibration. This effect becomes more pronounced for ultrasonic tools with larger cross-sections. The current study examines a 4.5″ × 6″ cross-section titanium horn which is designed to resonate axially at 20 kHz. Modeshapes and frequencies from 17–23 kHz are examined experimentally and using finite element analysis. The effect of design variables — slot length, slot width, and number of slots — on modeshapes and frequency spacing is shown. An optimum configuration based on the finite element results is prescribed. The computed results are compared with actual prototype data. Excellent correlation between analytical and experimental data is found.

Electrical Characterization of Low-Profile Copper Foil for Reduced Surface Roughness Loss

2016 ◽  
Vol 2016 (1) ◽  
pp. 000358-000363 ◽  
Author(s):  
Qianfei Su ◽  
A. Ege Engin ◽  
Jerry Aguirre
Keyword(s):  
Surface Roughness ◽  
Cross Sections ◽  
Transmission Lines ◽  
High Frequency ◽  
Printed Circuit Board ◽  
Electrical Characterization ◽  
Cavity Resonator ◽  
Circuit Board ◽  
Low Profile ◽  
Measure Surface Roughness

Abstract Signal attenuation in transmission lines is a major issue for reliable transmission in high frequency range. Knowledge of the electrical parameters of printed circuit board (PCB), including dielectric constant and loss tangent, is critical. Moreover, surface roughness has a great effect on loss in high frequency. This paper demonstrates an effective simulation fitting method for electrical material characterization. Cavity resonator is chosen as the circuit for characterization. A methodology is presented to measure surface roughness from cross sections, and compared with values extracted from resonator measurements. Several materials and copper foils treatments, including low-profile, are analyzed in this paper.

Recovery of High Frequency Phase of Laser Beam with Wavefront Distortion

2011 ◽  
Vol 38 (4) ◽  
pp. 0402009 ◽  
Author(s):  
付福兴 Fu Fuxing ◽  
张彬 Zhang Bin
Keyword(s):  
Laser Beam ◽  
High Frequency ◽  
Wavefront Distortion ◽  
Frequency Phase

Analysis on recovery effect of high frequency phase of laser beam with wavefront distortion

2013 ◽  
Vol 25 (10) ◽  
pp. 2505-2510
Author(s):  
贺也洹 He Yehuan ◽  
韩开 Han Kai ◽  
张彬 Zhang Bin
Keyword(s):  
Laser Beam ◽  
High Frequency ◽  
Recovery Effect ◽  
Wavefront Distortion ◽  
Frequency Phase

Scanning Capacitance Microscopy of Dopants in III-V Semiconductors

1998 ◽  
Vol 4 (S2) ◽  
pp. 640-641
Author(s):  
David V. Lang
Keyword(s):  
Quantum Well ◽  
Laser Beam ◽  
Surface Topography ◽  
Cross Sections ◽  
Beam Deflection ◽  
Doping Analysis ◽  
Scanning Capacitance Microscopy ◽  
Sample Spacing ◽  
Doping Profiles ◽  
Multi Quantum Well

Scanning Capacitance Microscopy (SCM) was first developed in 1985 as a method for sensing tip-to-sample spacing for surface topography profiling in connection with the RCA VideoDisc. Williams and coworkers were the first to use an SCM for obtaining dC/dV doping profiles in semiconductors, albeit with a rather modest resolution of 200 nm. More recently, it has been developed as a 50-nmresolution tool for microscopic doping analysis of semiconductors by measuring the tip-to-sample rf capacitance in an AFM controlled by other means, e.g. by laser beam deflection of a cantilever tip. In this paper we report on the application of SCM to study the 2D doping profiles of InP-based devices, such as multi-quantum well lasers.It is particularly convenient to prepare cross sections of III-V devices, since the material readily cleaves on [110] planes, as compared to silicon where cross sections must be obtained by painstaking polishing.

scholarly journals Natural Frequency Characteristics of the Beam with Different Cross Sections Considering the Shear Deformation Induced Rotary Inertia

2020 ◽  
Vol 10 (15) ◽  
pp. 5245
Author(s):  
Chunfeng Wan ◽  
Huachen Jiang ◽  
Liyu Xie ◽  
Caiqian Yang ◽  
Youliang Ding ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Cross Sections ◽  
Timoshenko Beam ◽  
High Frequency ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Equation Of Motion ◽  
Timoshenko Beam Theory ◽  
Rotary Inertia ◽  
Cross Sectional

Based on the classical Timoshenko beam theory, the rotary inertia caused by shear deformation is further considered and then the equation of motion of the Timoshenko beam theory is modified. The dynamic characteristics of this new model, named the modified Timoshenko beam, have been discussed, and the distortion of natural frequencies of Timoshenko beam is improved, especially at high-frequency bands. The effects of different cross-sectional types on natural frequencies of the modified Timoshenko beam are studied, and corresponding simulations have been conducted. The results demonstrate that the modified Timoshenko beam can successfully be applied to all beams of three given cross sections, i.e., rectangular, rectangular hollow, and circular cross sections, subjected to different boundary conditions. The consequence verifies the validity and necessity of the modification.

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