Technical Library | 2011-12-22 16:45:49.0
This paper reports the feasibility of using surface mount adhesives to produce low temperature microchannel arrays in a wide variety of metals. Sheet metal embossing and chemical etching processes have been used to produce sealing bosses that eliminate ch
OSU School of Mechanical, Industrial, and Manufacturing Engineering (MIME)
Technical Library | 2021-04-01 14:40:08.0
We demonstrate the viability of using ultra-thin sheets of microbially grown nanocellulose to build functional medical sensors. Microbially grown nanocellulose is an interesting alternative to plastics, as it is hydrophilic, biocompatible, porous, and hydrogen bonding, thereby allowing the potential development of new application routes. Exploiting
Technical Library | 2020-12-16 18:50:42.0
System operating speeds continue to increase as a function of the consumer demand for such technologies as faster Internet connectivity, video on demand, and mobile communications technology. As a result, new high performance PCB substrates have emerged to address signal integrity issues at higher operating frequencies. These are commonly called low Dk and/or low loss (Df) materials. The published "typical" values found on a product data sheet provide limited information, usually a single construction and resin content, and are derived from a wide range of test methods and test sample configurations. A printed circuit board designer or front end application engineer must be aware that making a design decision based on the limited information found on a product data sheet can lead to errors which can delay a product launch or increase the assembled PCB cost. The purpose of this paper is to highlight critical selection factors that go beyond a typical product data sheet and explain how these factors must be considered when selecting materials for high speed applications
Technical Library | 2014-04-10 18:04:04.0
This paper is meant to be a guide and a reference to new and old members alike who wish to know about, understand, and improve on the decisions made and processes implemented to build the current solar panels. The following paragraphs in the introduction will lay out background information on solar panels and cube satellites. This entire document was written with the idea that the reader will be able to follow the decisions made to construct the solar panels and then with this knowledge find areas of the project for improvement.
Technical Library | 2021-12-02 01:48:53.0
Some mechanical and assembly productions of existing companies of the Industry 3.0 and mechanical and assembly productions of perspective companies of the Industry 4.0 are described. The basic components of a smart factory and their interconnection to organize a production activity using humanless and paperless technologies are defined. A comparison analysis of parts and blanks movement to complete route sheet of the item manufacturing (radio and electronic item designing) in the companies of the Industry 3.0 and Industry 4.0 is given. The components of a digital item designing company to be created and implemented in the industry at first hand are defined.
University of Information Technologies, Mechanics and Optics [ITMO University]
Technical Library | 2017-03-09 17:37:05.0
This article focuses on the fabrication and characterization of stretchable interconnects for wearable electronics applications. Interconnects were screen-printed with a stretchable silver-polymer composite ink on 50-μm thick thermoplastic polyurethane. The initial sheet resistances of the manufactured interconnects were an average of 36.2 mΩ/◽, and half the manufactured samples withstood single strains of up to 74%. The strain proportionality of resistance is discussed, and a regression model is introduced. Cycling strain increased resistance. However, the resistances here were almost fully reversible, and this recovery was time-dependent. Normalized resistances to 10%, 15%, and 20% cyclic strains stabilized at 1.3, 1.4, and 1.7. We also tested the validity of our model for radio-frequency applications through characterization of a stretchable radio-frequency identification tag.
Technical Library | 2020-07-02 13:16:32.0
Principle of shielding 1 The principle of shielding is creating a conductive layer completely surrounding the object you want to shield. This was invented by Michael Faraday and this system is known as a Faraday Cage. 2 Ideally, the shielding layer will be made up of conductive sheets or layers of metal that are connected by means of welding or soldering, without any interruptions. The shielding is perfect when there is no difference in conductivity between the used materials. When dealing with frequencies below 30 MHz, the metal thickness affects shielding effectiveness. We also offer a range of shielding methods for plastic enclosures. A complete absence of interruptions is not a realistic goal since the Faraday cage will have to be opened from time to time so electronics, equipment or people can be moved in or out. Openings are also needed for displays, ventilation, cooling, power supply, signals etc. 3 Shielding works in both directions, items inside the shielded room are shielded from outside influences. (Fig. 3.1)
Technical Library | 2015-08-25 13:51:27.0
The stencil printing process is one of the most critical processes in the electronic production. Due to the requirement: "faster and smaller" it is necessary to place components with different paste volume close together without regard to solder paste printing. In our days it is no longer possible to control the solder paste volume only by adjustment of the aperture dimensions. The requirements of solder paste volumes for specific components are realized by different thicknesses of metal sheets in one stencil with so called step stencils. The step-down stencil is required when it is desirable to print fine-pitch devices using a thinner stencil foil, but print other devices using a thicker stencil foil. The paper presents the innovative technology of step-up and step-down stencils in a laser cutting and laser welding process. The step-up/step-down stencil is a special development for the adjustment of solder paste quantity, fulfilling the needs of placement and soldering. This includes the laser cutting and laser welding process as well as the resulting stencil characteristics and the potential of the printing process.
Technical Library | 2020-08-05 18:49:32.0
The evolution of internet-enabled mobile devices has driven innovation in the manufacturing and design of technology capable of high-frequency electronic signal transfer. Among the primary factors affecting the integrity of high-frequency signals is the surface finish applied on PCB copper pads – a need commonly met through the electroless nickel immersion gold process, ENIG. However, there are well-documented limitations of ENIG due to the presence of nickel, the properties of which result in an overall reduced performance in high-frequency data transfer rate for ENIG-applied electronics, compared to bare copper. An innovation over traditional ENIG is a nickel-less approach involving a special nano-engineered barrier designed to coat copper contacts, finished with an outermost gold layer. In this paper, assemblies involving this nickel-less novel surface finish have been subjected to extended thermal exposure, then intermetallics analyses, contact/sheet resistance comparison after every reflow cycle (up to 6 reflow cycles) to assess the prevention of copper atoms diffusion into gold layer, solder ball pull and shear tests to evaluate the aging and long-term reliability of solder joints, and insertion loss testing to gauge whether this surface finish can be used for high-frequency, high density interconnect (HDI) applications.
Technical Library | 2018-10-18 15:41:45.0
One specific market space of interest to emerging printed electronics is In Mold Label (IML) technology. IML is used in many consumer products and white good applications. When combined with electronics, the In Mold Electronics (IME) adds compelling new product functionality. Many of these products have multi-dimensional features and therefore require thermoforming processes in order to prepare the labels before they are in-molded. While thermoforming is not a novel technique for IML, the addition of printed electronic functional traces is not well documented. There is little or no published work on printed circuit performance and design interactions in the thermoforming process that could inform improved IME product designs. A general full factorial Design of Experiments (DOE) was used to analyze the electrical performance of the conductive silver ink trace/polycarbonate substrate system. Variables of interest include trace width, height of draw, and radii of both top and bottom curvatures in the draw area. Thermoforming tooling inserts were fabricated for eight treatment combinations of these variables. Each sample has one control and two formed strips. Electrical measurements were taken of the printed traces on the polymer sheets pre- and post- forming with a custom fixture to evaluate the effect on resistance. The design parameters found to be significant were draw height and bottom radius, with increased draw and smaller bottom curvature radii both contributing to the circuits’ resistance degradation. Over the ranges evaluated, the top curvature radii had no effect on circuit resistance. Interactions were present, demonstrating that circuit and thermoforming design parameters need to be studied as a system. While significant insight impacting product development was captured further work will be executed to evaluate different ink and substrate material sets, process variables, and their role in IME.
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