scholarly journals Substrate Materials Micromachining and Surface Considerations

1999 ◽  
Vol 4 (2) ◽  
pp. 35-39
Author(s):  
Bill Stockdale
Keyword(s):  
Manufacturing Processes ◽  
Dna Arrays ◽  
Surface Finishes ◽  
Design Function ◽  
Basic Approaches ◽  
Mechanical Devices ◽  
Subject Material ◽  
Microsystems Technology

Subject material presented describes substrate materials and their processing as key elements in microsystems technology manufacturing (MST) for Biochips (DNA arrays), Electronic MEMS (Micro-Electro-Mechanical) Devices and electro-optics. Material choices are primarily glass, quartz and silicon, each of which may require mechanical features and exact surface finishes to enable design function and manufacturing. This paper will address some basic approaches to determining what substrates require for specific designs and manufacturing processes.

Sequential Self-Folding of Shape Memory Polymer Sheets by Laser Rastering Toward Origami-Based Manufacturing

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
Moataz Abdulhafez ◽  
Joshua Line ◽  
Mostafa Bedewy
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Laser Source ◽  
Manufacturing Processes ◽  
New Approach ◽  
Surface Finishes ◽  
Polymer Sheets ◽  
Direct Laser ◽  
Number Of Passes

Abstract Origami-based fabrication strategies open the door for developing new manufacturing processes capable of producing complex three-dimensional (3D) geometries from two-dimensional (2D) sheets. Nevertheless, for these methods to translate into scalable manufacturing processes, rapid techniques for creating controlled folds are needed. In this work, we propose a new approach for controlled self-folding of shape memory polymer sheets based on direct laser rastering. We demonstrate that rapidly moving a CO2 laser over pre-strained polystyrene sheets results in creating controlled folds along the laser path. Laser interaction with the polymer induces localized heating above the glass transition temperature with a temperature gradient across the thickness of the thin sheets. This gradient of temperature results in a gradient of shrinkage owing to the viscoelastic relaxation of the polymer, favoring folding toward the hotter side (toward the laser source). We study the influence of laser power, rastering speed, fluence, and the number of passes on the fold angle. Moreover, we investigate process parameters that produce the highest quality folds with minimal undesired deformations. Our results show that we can create clean folds up to and exceeding 90 deg, which highlights the potential of our approach for creating lightweight 3D geometries with smooth surface finishes that are challenging to create using 3D printing methods. Hence, laser-induced self-folding of polymers is an inherently mass-customizable approach to manufacturing, especially when combined with cutting for integration of origami and kirigami.

Fractal-Based Characterization of Surface Texture

1992 ◽  
Vol 35 (3) ◽  
pp. 37-44
Author(s):  
Ken Grosser ◽  
Stephen Chesters ◽  
Hwa-Chi Wang ◽  
Gerhard Kasper
Keyword(s):  
Surface Roughness ◽  
Quality Assurance ◽  
Test Data ◽  
Surface Texture ◽  
High Purity ◽  
Measurement Method ◽  
Manufacturing Processes ◽  
Surface Finishes ◽  
Gas System

The surface roughness of high purity gas system distribution materials is a matter of concern for many critical manufacturing processes. Control of this roughness is thus much in demand and requires a sensitive measurement method. A refined fractal-based characterization is presented as a possible solution. Test data that use this method to compare various surface finishes and correlate roughness with surface cleanability are offered with explanations. This could become an effective quality assurance tool in those applications where surface roughness is important.

Bio-Inspired Self-Folding of Shape Memory Polymer Sheets by Laser Rastering

2020 ◽  
Author(s):  
Joshua Line ◽  
Moataz Abdulhafez ◽  
Mostafa Bedewy
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Manufacturing Processes ◽  
New Approach ◽  
Surface Finishes ◽  
Polymer Sheets ◽  
Direct Laser ◽  
Localized Heating ◽  
Number Of Passes

Abstract Origami-based fabrication strategies open the door for developing new manufacturing processes capable of producing complex three-dimensional (3D) geometries from two-dimensional (2D) sheets. Nevertheless, for these methods to translate into scalable manufacturing processes, rapid techniques for creating controlled folds are needed. In this work, we propose a new approach for controlled self-folding of shape memory polymer sheets based on direct laser rastering. We demonstrate that rapidly moving a CO2 laser over pre-strained polystyrene sheets results in creating controlled folds along the laser path. Laser interaction with the polymer induces localized heating above the glass transition temperature with a temperature gradient across the thickness of the thin sheets. This gradient of temperature results in a gradient of shrinkage owing to the viscoelastic relaxation of the polymer, favoring folding towards the hotter side. We study the influence of laser power, rastering speed and number of passes on the fold angle. Moreover, we investigate process parameters that produce the highest quality folds with minimal undesired deformations. Our results show that we clean folds up to and exceeding 90°, which highlights the potential of our approach for creating lightweight 3D geometries with smooth surface finishes that are challenging to create using 3D printing methods. Hence, laser-induced self-folding of polymers is an inherently mass-customizable approach to manufacturing, especially when combined with cutting for integration of origami and kirigami.

Specimen Collection Effect in Scanning Electron Microscopy Images

1972 ◽  
Vol 30 ◽  
pp. 448-449
Author(s):  
J. Temple Black ◽  
Jose Guerrero
Keyword(s):  
Surface Morphology ◽  
Secondary Electron Emission ◽  
Secondary Electrons ◽  
Charge Effects ◽  
Material Density ◽  
Specimen Collection ◽  
The Subject ◽  
Curved Paths ◽  
Subject Material ◽  
Microscopy Images

In the SEM, contrast in the image is the result of variations in the volume secondary electron emission and backscatter emission which reaches the detector and serves to intensity modulate the signal for the CRT's. This emission is a function of the accelerating potential, material density, chemistry, crystallography, local charge effects, surface morphology and especially the angle of the incident electron beam with the particular surface site. Aside from the influence of object inclination, the surface morphology is the most important feature In producing contrast. “Specimen collection“ is the name given the shielding of the collector by adjacent parts of the specimen, producing much image contrast. This type of contrast can occur for both secondary and backscatter electrons even though the secondary electrons take curved paths to the detector-collector.Figure 1 demonstrates, in a unique and striking fashion, the specimen collection effect. The subject material here is Armco Iron, 99.85% purity, which was spark machined.

The Computer in the Doctor’s Office

1981 ◽  
Vol 20 (04) ◽  
pp. 217-222 ◽  
Author(s):  
J. R. Möhr
Keyword(s):  
Conference Proceedings ◽  
Basic Approaches ◽  
Doctor's Office

Conclusions from an IMIA working conference on »The Computer in the Doctor’s Office« which took place in Hannover (FRG) in April 1980 are presented. The basis for these conclusions is outlined as a synthesis of the conference proceedings. Reasons for EDP application, basic approaches, achievable results and further trends are treated in detail.

Impact of fiber structure on edge-wicking of highly-sized paperboard

TAPPI Journal ◽  
2018 ◽  
Vol 17 (08) ◽  
pp. 437-443
Author(s):  
Lebo Xu ◽  
Jeremy Meyers ◽  
Peter Hart
Keyword(s):  
Fiber Surface ◽  
Manufacturing Processes ◽  
Paper Machine ◽  
Liquid Penetration ◽  
Fiber Structure ◽  
Cut Edge ◽  
Local Fiber

Coffee edge-wicking testing was conducted on two groups of highly-sized paperboard manufactured at two mills with similar manufacturing processes, but with vastly different local fiber sources. Although the Hercules size test (HST) indicated similar internal size levels between the two types of board, the edge-wicking behavior was noticeably different. Analysis of fiber structure revealed that the board with more edge-wicking had fibers with thicker fiber walls, which kept the fiber lumen more open after pressing and drying on a paper machine. It was demonstrated that liquid penetration through voids between fibers in highly-sized paperboard was limited, because the fiber surface was well protected by the presence of sufficient sizing agent. Nevertheless, freshly exposed fiber walls and lumens at the cut edge of the sheet were not protected by sizing material, which facilitated edge-wicking. The correlation between fiber structure and edge-wicking behavior was highlighted in this work to inspire development of novel sizing strategies that protect the freshly cut edge of the sheet from edge-wicking.

Translucent Glass Roofs For Large-Span Coverings

2019 ◽  
pp. 23-28
Keyword(s):  
Warm Season ◽  
Natural Light ◽  
Labor Costs ◽  
Main Bearing ◽  
Large Span ◽  
Glass Panels ◽  
Technical Properties ◽  
Internal Volume ◽  
Basic Approaches ◽  
Smoke Removal

The article deals with the issues of glass use in the enclosing structures of large-span coverings, which have such advantages as ensuring the penetration of natural light, tightness, minimum labor costs for repair and maintenance. Design shortcomings: the high cost, the need for protection of the internal volume against the penetrating sun rays in the warm season (hothouse effect); arrangement of devices for operation of a roof. The key technical properties and characteristics of glass panels and pane-glass sets, constructive decisions, including interface to the main bearing structures of a large-span covering are given. Peculiarities of their design with due regard for ventilation and smoke removal, a drainage of condensate, ways of fight against frosting and snow drifts on the roof are reflected. Features of the account of loadings, the basic approaches to their calculation are considered. Various design solutions for the spatial metal trussed systems with the original nodal connections are presented. Information on modern solutions of translucent roofs using glass for large-span coverings is given.

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