Technical Library | 2022-08-08 15:06:06.0
Selective soldering has evolved to become a standard production process within the electronics assembly industry, and now accommodates a wide variety of through-hole component formats in numerous applications. Most through-hole components can be easily soldered with the selective soldering process without difficulty however some types of challenging components require additional attention to ensure that optimum quality is maintained. Several high thermal mass components can place demands on the selective soldering process, while the use of specialized solder fixtures, or solder pallets, often places additional thermal demand on the preheating process. Fine-pitch through-hole components and connectors place a different set of demands on the selective soldering process and typically require special attention to lead projection and traverse speed to minimize bridging between adjacent pins. Dual in-line memory module (DIMM) connectors, compact peripheral component interface (cPCI) connectors, coax connectors and other high thermal mass components as well as fine-pitch microconnectors, can present challenges when soldered into backplanes or multilayer printed circuit board assemblies. Adding to this challenge, compact peripheral component interface connectors can present additional solderability issues because of their beryllium copper base metal pins. Key Terms: Selective soldering, drop-jet fluxing, sustained preheating, flux migration, adjacent clearance, lead-to-hole aspect ratio, lead projection, thermal reliefs, gold embrittlement, solderability testing.
Technical Library | 2021-05-06 13:48:05.0
In this paper most commonly occurring Bare PCB defects such as Track Cut, Track short and Pad Damages are detected by Image processing techniques. Reference PCB without having any defects is compared with test PCB having defects to identify the defects and x-y coordinates of the center of the defects along with radii are obtained using Difference of Gaussian method and location of the individual type of defects are marked either by similar color or different colors. Result Analysis includes time taken for the inspection of a single defect, multiple similar defects, and multiple different defects. Time taken is ranging from 1.674 to 1.714 seconds if the individual type of defects are marked by different colors and 0.670 to 0.709 seconds if all the identified defects are marked by the same colors.
Technical Library | 2021-04-15 14:39:41.0
Inspection of printed circuit board (PCB) has been a crucial process in the electronic manufacturing industry to guarantee product quality & reliability, cut manufacturing cost and to increase production. The PCB inspection involves detection of defects in the PCB and classification of those defects in order to identify the roots of defects. In this paper, all 14 types of defects are detected and are classified in all possible classes ...
Technical Library | 2017-04-13 16:14:27.0
The drive to reduced size and increased functionality is a constant in the world of electronic devices. In order to achieve these goals, the industry has responded with ever-smaller devices and the equipment capable of handling these devices. The evolution of BGA packages and leadless devices is pushing existing technologies to the limit of current assembly techniques and materials.As smaller components make their way into the mainstream PCB assembly market, PCB assemblers are reaching the limits of Type 3 solder paste, which is currently in use by most manufacturers.The goal of this study is to determine the impact on solder volume deposition between Type 3, Type 4 and Type 5 SAC305 alloy powder in combination with stainless steel laser cut, electroformed and the emerging laser cut nano-coated stencils. Leadless QFN and μBGA components will be the focus of the test utilizing optimized aperture designs.
Technical Library | 2021-11-29 01:10:58.0
ASHCROFT pressure transmitter is one of the most commonly used transmitters in industrial applications. It is widely used in a variety of control environments, involving water conservancy and hydropower, railway transportation, intelligent building, production automation, aerospace, military, petrochemical, oil wells, electric power, ships, machine tools and pipelines. ASHCROFT pressure transmitter is an electronic device that senses the pressure signal and converts it into an available output electrical signal according to certain rules.
Technical Library | 2019-02-13 13:45:11.0
Development of information and telecommunications network is outstanding in recent years, and it is required for the related equipment such as communication base stations, servers and routers, to process huge amount of data in no time. As an electrical signal becomes faster and faster, how to prevent signal delay by transmission loss is a big issue for Printed Circuit Boards (PCB) loaded on such equipments. There are two main factors as the cause of transmission loss; dielectric loss and conductor loss. To decrease the dielectric loss, materials having low dielectric constant and low loss tangent have been developed. On the other hand, reducing the surface roughness of the copper foil itself to be used or minimizing the surface roughness by modifying surface treatment process of the conductor patterns before lamination is considered to be effective in order to decrease the conductor loss. However, there is a possibility that reduction in the surface roughness of the conductor patterns will lead to the decrease in adhesion of conductor patterns to dielectric resin and result in the deterioration of reliability of PCB itself. In this paper, we will show the evaluation results of adhesion performance and electrical properties using certain type of dielectric material for high frequency PCB, several types of copper foil and several surface treatment processes of the conductor patterns. Moreover, we will indicate a technique from the aspect of surface treatment process in order to ensure reliability and, at the same time, to prevent signal delay at the signal frequency over 20 GHz.
Technical Library | 2019-05-23 21:56:56.0
Automatic on-line shoe sole spraying system: automatic shoe sole spraying system, simple and convenient operation, using 3D vision positioning system. Automatic recognition and automatic generation of spraying trajectory. Robot non-contact spraying gun is used to complete the process of shoe sole spraying with maturity, stability, high speed and high precision along the predetermined trajectory. The automatic generation of spraying trajectory is the realization of shoe sole spraying technology. Shoe sole spraying characteristics: 1.Positioning System: 3D Visual Positioning 2.Components: Intelligent Robot, Laser Scanner, Industrial Computer, Gum Spraying System, Conveyor Belt, Electrical Control System, etc. 3.Spraying time: slightly different according to shoe size and spraying time Fully automatic sole spraying advantages: 1. Simple application: suitable for soles of different specifications, models and sizes 2. Faster speed: 6-8 seconds to complete sole scanning and spraying, superior to similar products at home and abroad. 3. Quality stability: gum spraying trajectory is scheduled, gum dosage is fixed, gum spraying quality is greatly improved. 4. High cost performance: the same performance, the price is only 1/3 of the same type of equipment of European brand. 5. Reduce wear and tear: glue is fully utilized and not wasted, reducing human contact with glue. Intelligent operation advantage manual only need general operation can be automated workshop, mechanical arm automatic spraying glue, accurate spraying, reduce glue waste. Environmental protection effect of long-term close contact with glue seriously affects human health and mechanical work, glue does not directly contact, do not harm the human body. Fully automatic spraying, shoe sole adhesion process for automatic spraying machine, will not cause great challenges! With the deepening of personalized shoemaking, higher requirements have been put forward for the spraying technology in shoemaking process. The method of creating spraying trajectory must be adapted to shoes of different sizes and styles. The automatic generation of spraying trajectory is one of the key technologies to realize the automation of shoe sole spraying process. The method of off-line programming and real-time generation of spraying trajectory for robots based on the three-dimensional CAD model of sole and the data of sole. A new method of generating spray trajectory by scanning the sole of shoe upper with linear structured light sensor is presented. The feasibility of the method is verified by industrial robots. Aiming at the need of generating shoe sole spray rubber trajectory based on line structured light, the format standard of IGES file of three-dimensional model of shoe sole was tested. The shoe sole contour line and the shoe sole surface were extracted, and then the offset curve of the shoe sole contour line on the shoe sole surface was calculated to obtain the spray rubber trajectory. Three-dimensional profilometer is to use structured light to obtain sole information, effectively improve the automatic shoemaking spraying process, which will help to improve the efficiency of shoemaking, improve the quality of footwear products, and promote the development of personalized shoemaking.
Technical Library | 2019-02-06 22:02:08.0
The High Density Packaging (HDP) user group has completed a project to evaluate the majority of viable Dk (Dielectric Constant)/Df (Dissipation Factor) and delay/loss electrical test methods, with a focus on the methods used for speeds above 2 GHz. A comparison of test methods from 1 to 2 GHz through to higher test frequencies was desired, testing a variety of laminate materials (standard volume production with UL approval, low loss, and "halogen-free" laminate materials). Variations in the test board material resin content/construction and copper foil surface roughness/type were minimized. Problems with Dk/Df and loss test methods and discrepancies in results are identified, as well as possible correlations or relationships among these higher speed test methods.
Technical Library | 2020-04-08 22:57:04.0
Flexible hybrid electronics (FHE), designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas.
Technical Library | 2021-10-20 18:21:06.0
The solderability of the SAC305 alloy in contact with printed circuit boards (PCB) having different surface finishes was examined using the wetting balance method. The study was performed at a temperature of 260 _C on three types of PCBs covered with (1) hot air solder leveling (HASL LF), (2) electroless nickel immersion gold (ENIG), and (3) organic surface protectant (OSP), organic finish, all on Cu substrates and two types of fluxes (EF2202 and RF800). The results showed that the PCB substrate surface finish has a strong effect on the value of both the wetting time t0 and the contact angle h. The shortest wetting time was noted for the OSP finish (t0 = 0.6 s with EF2202 flux and t0 = 0.98 s with RF800 flux), while the ENIG finish showed the longest wetting time (t0 = 1.36 s with EF2202 flux and t0 = 1.55 s with RF800 flux). The h values calculated from the wetting balance tests were as follows: the lowest h of 45_ was formed on HASL LF (EF2202 flux), the highest h of 63_ was noted on the OSP finish, while on the ENIG finish, it was 58_ (EF2202 flux). After the solderability tests, the interface characterization of cross-sectional samples was performed by means of scanning electron microscopy coupled with energy dispersive spectroscopy.
