Technical Library | 2017-06-13 17:14:59.0
For tin-rich solder alloys, 200 C (392 F) is an extreme temperature. Intermetallic growth in tin-copper systems is known to occur and is believed to bear a direct relationship to failure mechanisms. This study of morphological changes with time at elevated temperatures was made to determine growth rates of tin-copper intermetallics. Preferred growth directions, rates of thickening, and notable changes in morphology were observed.Each of four tin-base alloys was flowed on copper and exposed to temperatures between 100 C and 200 C for time periods of up to 32 days. Metallographic sections were taken and the intermetallics were examined. Intermetallic layer thickening is characterized by several distinct stages. The initial growth of side plates is extremely rapid and exaggerated. This is followed by retrogression (spheroidization) of the elongated peaks and by general thick-
Technical Library | 2010-09-30 21:07:29.0
As technology is much more advanced nowadays, electronic devices are ubiquitous in our daily life. PCB (Printed Circuit Board) plays an important role in almost every modern electronic device. However, there still is not a perfect PCB manufacturing proces
Technical Library | 2018-04-11 22:18:05.0
Millimeter-wave (mmWave) frequency applications are becoming more common. There are applications utilizing PCB technology at 60 GHz, 77 GHz and many other mmWave frequencies. When designing a PCB for mmWave frequency, the properties of the circuit materials need to be considered since they can be critical to the success of the application. Understanding the properties of circuit materials at these frequencies is very important.This paper will give an overview of which circuit material properties are important to mmWave frequency applications using PCBs. There will be data supplied which demonstrates why these properties are essential to the circuit material selection for mmWave applications. Some properties discussed will be dielectric constant (Dk) control, dissipation factor, moisture absorption, thickness control and TCDk (Temperature Coefficient of Dk). Measured comparisons will be shown for insertion loss and Dk versus frequency for different types of circuit materials up to 110 GHz. As part of the test data, the impact on circuit performance due to TCDk and moisture absorption will be shown at mmWave frequencies.
Technical Library | 2008-11-13 00:06:32.0
The electronics industry is facing issues with hot spots, solder joint stresses and Coefficient of Thermal Expansion (CTE) mismatch between PCB and IC substrate. Flip chip type packages for example have very low CTE compared to traditional PCB material. Thus it is necessary to have low CTE printed circuit boards in order to keep solder joint intact with such low CTE packages. There are currently several materials available in the market to address thermal and CTE challenges but each material has its own advantages and limitations...
Technical Library | 2015-06-22 16:39:47.0
Surface finishing is an integral part of any PCB fabrication. It is generally applied to exposed Cu connectors and conductors on the board. Surface finishing has numerous important functions. It serves as a protective layer for the Cu connectors during storage. The surface finish helps minimize or reduce tarnish of the Cu substrate. Additionally, since it is the layer that comes into contact with other components during assembly, it ensures good solderability between the PCB and the component during assembly. Furthermore after assembly, the finish helps prolong the integrity of the solder joint during use. A general review of common PCB surface finishes is presented. The advantages and disadvantages of each are discussed and compared.
Technical Library | 2019-05-29 01:47:22.0
1.Vias near SMD pads: Solder can flow into the via after melted. As a result cold joint will appear in the end. Check the picture below. 2.Vias on SMD pads: Solder can flow into the via more easier after melted. Check the picture below. 3.Via opening without soldermask covered. When workers solder TH parts by hand, soldering iron can touch vias sometime, then tiny amounts molten solder will stay on vias. This can lead to electrical short easily. We recommend you make all vias tenting (covered by solder mask) if it is possible.
PCBNPI-Professional PCB Fab/PCB Assembly Service Provider From China
Technical Library | 2019-02-05 13:43:14.0
SonoFlux Servo with InSight automated board recognition system helps PCB manufacturers take steps toward greater automation and traceability and the goal of Industry 4.0.
Technical Library | 2023-05-02 18:50:24.0
Surface-mount PCB components are smaller than their lead-based counterparts and provide a radically higher component density. They are available in a variety of shapes and sizes designated by a series of standardized codes curated by the electronics industry. Of these PCB components, the 0201-sized are the smallest, measuring 0.024 x 0.012 in. (0.6 x 0.3 mm) – that's 70% smaller than the previous 0402 level! The 0201 components are designed to improve reliability in space-constrained applications such as portable electronics like smartphones, tablets, robotics and digital cameras, but require delicate handling during the assembly process. Given the miniaturized dimensions of an 0201 package, it is crucial that the mounting process abide by a series of guidelines regarding the design of the PCB mounting pads and solderable metallization, PCB circuit trace width, solder paste selection, package placement and overages, solder paste reflow, solder stencil screening, and final inspection. It's advisable that one review this information when procuring the services of a PCB assembler.
Technical Library | 2017-11-08 23:22:04.0
Due to the ongoing trend towards miniaturization of power components, the need for increased thermal conductivity of solder joints in SMT processes gains more and more importance. Therefore, the role of void free solder joints in power electronics becomes more central. Voids developed during soldering reduce the actual thermal transfer and can cause thermal damage of the power components up to their failure. For this reason, the company has developed a new technique to minimize the formation of these voids during the soldering process.
Technical Library | 2023-11-14 19:33:57.0
Wave soldering is an established technology and is commonly used where large unit volumes occur with low product variety. However, if a wave soldering machine is getting old or if technological changes or new PCB designs limits its manufacturing capabilities, consideration should be given to whether selective soldering would be a better choice. Anyone who deals with soldering through-hole and surface mount mixed-technology printed circuit assemblies will quickly discover that a selective soldering machine is not only less expensive that wave soldering, but selective soldering also offers the opportunity to meet customer requirements with significantly more flexibility. One such company is Thomas Preuhs GmbH. Located in Geislingen, Germany, Thomas Preuhs GmbH manufactures a variety of electronic assemblies for solar and HVAC data systems, automotive and white goods products as well as electric drive systems.
Products, services, training & consulting for the assembly, rework & repair of electronic assemblies. BGA process experts. Manufacturers Rep, Distributor & Service Provider for Seamark/Zhuomao and Shuttle Star BGA Rework Stations.
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