Surface Profile Accuracy of Deployable Mesh Reflectors Based on Focal Offset

2021 ◽  
pp. 1355-1365
Author(s):  
Shenoy S. Siddesh ◽  
R. Harisankar ◽  
G. K. Ananthasuresh
Keyword(s):  
Surface Profile ◽  
Profile Accuracy ◽  
Focal Offset

Fabrication and Characterization of 3D Aspheric Microlenses with Arbitrary Surface Profiles Based on a Novel Excimer Laser Contour Scanning Method

2006 ◽  
Vol 505-507 ◽  
pp. 67-72
Author(s):  
Yung Chun Lee ◽  
Chun Ying Wu
Keyword(s):  
Excimer Laser ◽  
Surface Profile ◽  
Aspheric Surfaces ◽  
Scanning Method ◽  
System A ◽  
Continuous Surface ◽  
Surface Profiles ◽  
Profile Accuracy ◽  
Method Show

This paper presents a new method for fabricating 3D microstructures with an excimer laser micromachining system. A novel mask contour scanning method is developed for obtaining precise 3D microstructures with pre-described continuous surface profile. Two different microlenses with spherical and aspheric surfaces profiles with dimension less than 200 μm are fabricated on polycarbonate (PC) samples. The surface profiles are measured and compared with their theoretical counterparts. Excellent agreements both in profile shapes and dimensions are achieved. The surface roughness (Ra) of the machined surfaces is also measured and is less than 10 nm. The machining profile accuracy and surface smoothness of this proposed micromachining method show great potentials in fabricating micro-optic components such as aspheric microlenses or microlens arrays.

Spherical and Aspheric Microlenses Fabricated by Excimer Laser LIGA-like Process

2006 ◽  
Vol 129 (1) ◽  
pp. 126-134 ◽  
Author(s):  
Yung-Chun Lee ◽  
Chun-Ming Chen ◽  
Chun-Ying Wu
Keyword(s):  
Surface Roughness ◽  
Excimer Laser ◽  
Focal Length ◽  
Surface Profile ◽  
Polymer Materials ◽  
Laser Machining ◽  
Scanning Method ◽  
Average Surface ◽  
Direct Laser ◽  
Profile Accuracy

This paper presents an effective and low-cost method for fabricating spherical and aspheric microlenses based on excimer laser LIGA-like processes. It is based on a newly developed excimer laser micromachining technique that can accurately machine a 3D microstructure with a predetermined continuous surface profile. The method is called the planetary scanning method since it is based on a combination of sample rotation and revolution and a concept of laser machining probability. Spherical and aspheric microlenses with precise and smooth surface profiles are fabricated by direct laser machining on polymer materials. Laser-machined microlenses are replicated by electroforming to obtain inverse metal molds. Finally, plastic microlenses are replicated from these metal molds using hot embossing method. The profile accuracy and surface roughness of the produced microlenses at each stage have been measured and monitored. The average surface profile accuracy is better than 1μm and average surface roughness is less than 10nm. Optical performance of the fabricated microlenses is evaluated by measuring the light intensity distribution at the focal plane and the focal length. Experimental data show that the characteristics of fabricated spherical and aspheric microlenses are well matched to the theoretical predictions, which demonstrates the controllability and accuracy of this micromachining process. Potential applications and further developments will be addressed.

scholarly journals Study of the Effect of Process Parameters on Surface Profile Accuracy in Single-Point Incremental Sheet Forming of AA1050-H14 Aluminum Alloy

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Abdulmajeed Dabwan ◽  
Adham E. Ragab ◽  
Mohamed A. Saleh ◽  
Saqib Anwar ◽  
Atef M. Ghaleb ◽  
...  
Keyword(s):  
Surface Quality ◽  
Process Parameters ◽  
Incremental Forming ◽  
Single Point ◽  
Surface Profile ◽  
Sheet Thickness ◽  
Numerical Control ◽  
Single Point Incremental Forming ◽  
Tool Diameter ◽  
Profile Accuracy

Single-point incremental forming is an innovative flexible and inexpensive technique to form sheet products when prototypes or small batches are required. The process allows complex geometries to be produced using a computer numerical control machine, eliminating the need for a special die. This study reports on the effects of four important single-point incremental forming process parameters on produced surface profile accuracies. The profile accuracy was estimated by measuring the side angle errors and surface roughness and also waviness and circularity of the product inner surface. Full factorial design of experiments was used to plan the study, and the analysis of variance was used to analyze and interpret the results. The results indicate that the tool diameter (d), step depth (s), and sheet thickness (t) have significant effects on the produced profile accuracy, while the feed rate (f) is not significant. As a general rule, thin sheets with greater tool diameters yielded the best surface quality. The results also show that controlling all surface quality features is complex because of the contradicting effects of, and interactions between, a number of the process parameters.

Rubber–Road Contact: Comparison of Physics-Based Theory and Indoor Experiments

2016 ◽  
Vol 44 (3) ◽  
pp. 150-173 ◽  
Author(s):  
Mehran Motamedi ◽  
Saied Taheri ◽  
Corina Sandu
Keyword(s):  
Rough Surface ◽  
Practical Importance ◽  
Surface Profile ◽  
Surface Characteristics ◽  
Mechanical Analysis ◽  
Friction Model ◽  
Rubber Friction ◽  
Optical Profilometer ◽  
Viscoelastic Modulus ◽  
Longitudinal Slip

ABSTRACT For tire designers, rubber friction is a topic of pronounced practical importance. Thus, development of a rubber–road contact model is of great interest. In this research, to predict the effectiveness of the tread compound in a tire as it interacts with the pavement, the physics-based multiscale rubber-friction theories developed by B. Persson and M. Klüppel were studied. The strengths of each method were identified and incorporated into a consolidated model that is more comprehensive and proficient than any single, existing, physics-based approach. In the present work, the friction coefficient was estimated for a summer tire tread compound sliding on sandpaper. The inputs to the model were the fractal properties of the rough surface and the dynamic viscoelastic modulus of rubber. The sandpaper-surface profile was measured accurately using an optical profilometer. Two-dimensional parameterization was performed using one-dimensional profile measurements. The tire tread compound was characterized via dynamic mechanical analysis. To validate the friction model, a laboratory-based, rubber-friction test that could measure the friction between a rubber sample and any arbitrary rough surface was designed and built. The apparatus consisted of a turntable, which can have the surface characteristics of choice, and a rubber wheel in contact with the turntable. The wheel speed, as well as the turntable speed, could be controlled precisely to generate the arbitrary values of longitudinal slip at which the dynamic coefficient of friction was measured. The correlation between the simulation and the experimental results was investigated.

Device for 3 D Surface Profile Measurements

2010 ◽  
Vol 1 (2) ◽  
pp. 116-122
Author(s):  
Sanjeev K. Gupta ◽  
Abhijit Kushari ◽  
Chandra S. Upadhyay ◽  
Comandur Venkatesan
Keyword(s):  
Surface Profile

Modification of the n-Surface Profile of AlGaInN LEDs by Changing the Gas-Mixture Composition During Reactive Ion Etching

2020 ◽  
Vol 54 (6) ◽  
pp. 672-676
Author(s):  
L. K. Markov ◽  
I. P. Smirnova ◽  
M. V. Kukushkin ◽  
A. S. Pavluchenko
Keyword(s):  
Reactive Ion Etching ◽  
Surface Profile ◽  
Mixture Composition ◽  
Gas Mixture ◽  
Ion Etching

scholarly journals Shaping Dynamical Casimir Photons

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 189
Author(s):  
Diego A. R. Dalvit ◽  
Wilton J. M. Kort-Kamp
Keyword(s):  
Optical Properties ◽  
Lattice Structure ◽  
Casimir Effect ◽  
Surface Profile ◽  
Microscopic Theory ◽  
Space Time ◽  
Quantum Vacuum ◽  
Dynamical Casimir Effect ◽  
Photon Pairs ◽  
Time Quantum

Temporal modulation of the quantum vacuum through fast motion of a neutral body or fast changes of its optical properties is known to promote virtual into real photons, the so-called dynamical Casimir effect. Empowering modulation protocols with spatial control could enable the shaping of spectral, spatial, spin, and entanglement properties of the emitted photon pairs. Space–time quantum metasurfaces have been proposed as a platform to realize this physics via modulation of their optical properties. Here, we report the mechanical analog of this phenomenon by considering systems in which the lattice structure undergoes modulation in space and in time. We develop a microscopic theory that applies both to moving mirrors with a modulated surface profile and atomic array meta-mirrors with perturbed lattice configuration. Spatiotemporal modulation enables motion-induced generation of co- and cross-polarized photon pairs that feature frequency-linear momentum entanglement as well as vortex photon pairs featuring frequency-angular momentum entanglement. The proposed space–time dynamical Casimir effect can be interpreted as induced dynamical asymmetry in the quantum vacuum.

scholarly journals The Surface Condition of Ni-Cr after SiC Abrasive Blasting for Applications in Ceramic Restorations

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5824
Author(s):  
Weronika Czepułkowska-Pawlak ◽  
Emilia Wołowiec-Korecka ◽  
Leszek Klimek
Keyword(s):  
Surface Condition ◽  
Abrasive Particle ◽  
Surface Profile ◽  
Abrasive Particles ◽  
Dental Restorations ◽  
Large Width ◽  
Ceramic Restorations ◽  
The Impact ◽  
Abrasive Size ◽  
Abrasive Blasting

Abrasive blasting is a process widely used in dentistry. One of the uses is the development of metal surfaces for connections with ceramics in fixed prosthetic restorations. The purpose of this paper was to check how the rough surface profile (width, height, and depth on unevenness) impacts the surface’s condition, like its wettability and percentage of stuck abrasives. The Ni-Cr alloy surface was abrasive blasted by silicon carbide with the various pressure parameters (0.2, 0.4, and 0.6 MPa) and abrasive particle sizes (50, 110, and 250 µm). Cleaned surfaces were examined for roughness, wettability, and percentage of stuck abrasive particles on the surface. The surface after abrasive blasting using 110 µm of abrasive size and 0.4 MPa pressure has the best wettability results. The width of unevenness may cause it. When the unevenness has too small or too large width and depth, the fluids may not cover the entire cavities because of locking the air. The surface condition of dental alloys directly affects metal–ceramic connection strength. The knowledge about the impact of the abrasive blasting parameters on the bond strength will allow one to create durable dental restorations.

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