Technical Library | 2017-12-21 11:24:05.0
The present work concerns on the use of sensors to monitor the structural health of wind turbine . Conventionally the inspection was made using non-contact sensing during the turbine’s inoperable period hence loss occurred. A real -time monitoring system via embedded wireless sensor is preferred but the sensor could only be implanted using non-contact printing method due to most turbine blade s’ curved surface. Conductive ink associate d with non-contact printing method via fluid dispensing system are proposed since conductive inks are proven stretchable and fluid dispensing system enables printing on various substrates and works well with any materials...
Technical Library | 2020-10-08 00:55:22.0
This article presents the development of a stretchable sensor network with high signal-to-noise ratio and measurement accuracy for real-time distributed sensing and remote monitoring. The described sensor network was designed as an island-and-serpentine type network comprising a grid of sensor "islands" connected by interconnecting "serpentines." A novel high-yield manufacturing process was developed to fabricate networks on recyclable 4-inch wafers at a low cost. The resulting stretched sensor network has 17 distributed and functionalized sensing nodes with low tolerance and high resolution. The sensor network includes Piezoelectric (PZT), Strain Gauge(SG), and Resistive Temperature Detector (RTD) sensors. The design and development of a flexible frame with signal conditioning, data acquisition, and wireless data transmission electronics for the stretchable sensor network are also presented. The primary purpose of the frame subsystem is to convert sensor signals into meaningful data, which are displayed in real-time for an end-user to view and analyze. The challenges and demonstrated successes in developing this new system are demonstrated, including (a) developing separate signal conditioning circuitry and components for all three sensor types (b) enabling simultaneous sampling for PZT sensors for impact detection and (c)configuration of firmware/software for correct system operation. The network was expanded with an in-house developed automated stretch machine to expand it to cover the desired area. The released and stretched network was laminated into an aerospace composite wing with edge-mount electronics for signal conditioning, processing, power, and wireless communication.
Technical Library | 2008-03-31 21:35:36.0
While the situation varies from country to country, nearly one year after the EU RoHS Directive came into force implementation of lead-free solder is progressing steadily. For lead-free soldering to be considered successful it is not sufficient just to have dealt with the challenges of mass production. It is also necessary to establish that the soldered joints produced are at least as reliable as those made with Sn-37Pb alloy. In this context "reliability" means the length of time in service that the initial functionality of the joint can be maintained. In this paper we will discuss some of the issues involved in solder joint reliability through a comparison of the properties of two alloys that are widely used for lead-free wave soldering, SAC305 (Sn-3.0Ag-0.5Cu) and the Sn, Cu, Ni, Ge alloy SN100C.
Technical Library | 2011-01-20 19:50:30.0
This article introduces the technical development that went in to realizing an 80-layer ultra-multilayer printed circuit board, which meets the market demand for a "semiconductor test board supporting memory increases".
Technical Library | 2009-11-24 23:00:34.0
With the introduction of 01005 chip components and 0.3 mm pitch CSP devices, electronic component packaging is pushing surface mount technology to the limits of its potential. Miniaturization is driving the electronics industry to implement the smallest and tightest pitch components in order to meet their customer demands. But how much miniaturization is possible before there is a paradigm shift in the technology? At what point is solder paste no longer viable? How small of a feature can be printed with solder paste, and can this process be implemented into a production environment?
Technical Library | 2019-10-03 14:27:01.0
Knowing how package warpage changes over temperature is a critical variable in order to assemble reliable surface mount attached technology. Component and component or component and board surfaces must stay relatively flat with one another or surface mount defects, such as head-in-pillow, open joints, bridged joints, stretched joints, etc. may occur. Initial package flatness can be affected by numerous aspects of the component manufacturing and design. However, change in shape over temperature is primarily driven by CTE mismatch between the different materials in the package. Thus material CTE is a critical factor in package design. When analyzing or modeling package warpage, one may assume that the package receives heat evenly on all sides, when in production this may not be the case. Thus, in order to understand how temperature uniformity can affect the warpage of a package, a case study of package warpage versus different heating spreads is performed.Packages used in the case study have larger form factors, so that the effect of non-uniformity can be more readily quantified within each package. Small and thin packages are less prone to issues with package temperature variation, due to the ability for the heat to conduct through the package material and make up for uneven sources of heat. Multiple packages and multiple package form factors are measured for warpage via a shadow moiré technique while being heated and cooled through reflow profiles matching real world production conditions. Heating of the package is adjusted to compare an evenly heated package to one that is heated unevenly and has poor temperature uniformity between package surfaces. The warpage is measured dynamically as the package is heated and cooled. Conclusions are drawn as to how the role of uneven temperature spread affects the package warpage.
Technical Library | 2013-09-19 17:25:32.0
The next generation of smart phones will demand very thin multi-layer boards to reduce the product thickness again. This paper shows three different manufacturing approaches, which can be used for very thin any-layer build-ups. The technological approaches are compared on reliability level – the any-layer copper filled micro-via technology which is to be considered as state of the art technology for high end phones and the ALIVH-C/G technology that is well established in Japan. A test vehicle design featuring test coupons for comprehensive reliability test series has been defined as target application for investigation...
Technical Library | 2014-05-15 14:26:27.0
350mA). Slotted surface showed good performance on both thermal and optical properties of the given 3W green LED.