Technical Library | 2008-01-24 21:42:39.0
Although many through-hole components are being replaced by their surface mount (SMT) counterparts, printed circuit boards (PCBs) are still being designed with both types of components. Often, there are interconnect hardware, displays, or other components that cannot withstand the exposure to the high temperature involved in the wave soldering process. They are generally soldered by hand. The challenge is to determine the optimal method manufacturers can use to solder these boards populated with mixed technology.
Technical Library | 2012-02-09 15:26:56.0
The Fundamentals of Signature Analysis Technical document discusses the basics of power-off analog signature analysis, how it relates to basic electronic devices and how it is used for circuit board troubleshooting.
Technical Library | 2010-04-15 20:42:44.0
The high level of current interest in embedded passives in printed circuit boards is driven by the tremendous pressure to pack more circuitry into smaller spaces. However, adoption has been limited due to design, prototyping and infrastructure issues, as well as the stability and tolerances necessary for widespread replacement of discretes. The focus of this work has been to develop a polymer thick film resistor technology to incorporate reliable organic resistors inside printed wiring boards using standard PWB processing.
Technical Library | 1999-08-09 11:11:55.0
A great deal of controversy continues to surround the use of Hot Air Solder Leveling (HASL) in the production of printed circuit boards (PCBs). The financial burden, technological limitations and environmental issues surrounding the HASL process continue to grow. This requires an in-depth review by the printed circuit board manufacturing plant, as well as the assembly operation and instrument designers ( OEMs), to determine what alternative surface finishes are appropriate.
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 | 2016-09-06 04:54:27.0
Printed circuit boards are the base of electronic products in a variety of consumer and industrial applications. New PCBs always perform well. However, their performance will deteriorate with time due to exposure to different environmental conditions like condensation, moisture, contamination of the iconic material on the surface, dust and dirt, mildew, alpha particles, etc. To avoid these problems, PCBs are protected with conformal coatings. Let’s see how this is done, and how they protect PCB components.
Technical Library | 2017-01-24 02:15:49.0
Basic performance of PCB (Printed Circuit Board) depends on the performance of substrate material. In order to improve the performance of PCB, you have to increase the performance of PCB substrate material first. This article introduces how to chose PCB substrate material for your custom PCB project from multiple perspectives.
Technical Library | 2013-11-27 16:54:01.0
The need in complexity for microwave space products such as active BFNs (Beam Forming Networks) is increasing, with a significantly growing number of amplitude / phase control points (number of beams * numbers of radiating elements). As a consequence, the RF component’s package topology is evolving (larger number of I/Os, interconnections densification ...) which directly affect the routing and architecture of the multilayer boards they are mounted on. It then becomes necessary to improve the density of these boards (...) This paper will present the work performed to achieve LCP-based high density multilayer structures, describing the different electrical and technological breadboards manufactured and tested and presenting the results obtained.
Technical Library | 2019-08-15 13:31:52.0
Cracks in ceramic chip capacitors can be introduced at any process step during surface mount assembly. Thermal shock has become a "pat" answer for all of these cracks, but about 75 to 80% originate from other sources. These sources include pick and place machine centering jaws, vacuum pick up bit, board depanelization, unwarping boards after soldering, test fixtures, connector insulation, final assembly, as well as defective components. Each source has a unique signature in the type of crack that it develops so that each can be identified as the source of error.
Technical Library | 2010-03-18 14:02:03.0
Selecting products that have been qualified by industry standards for use in printed circuit board assembly processes is an accepted best practice. That products which have been qualified, when used in combinations not specifically qualified, may have resultant properties detrimental to assembly function though, is often not adequately understood. Printed circuit boards, solder masks, soldering materials (flux, paste, cored wire, rework flux, paste flux, etc.), adhesives, and inks, when qualified per industry standards, are qualified using very specific test methods which may not adequately mimic the assembly process ultimately used.