Technical Library | 2023-05-02 19:06:43.0
As 0402 has become a common package for printed circuit board (PCB) assembly, research and development on mounting 0201 components is emerging as an important topic in the field of surface mount technology for PWB miniaturization. In this study, a test vehicle for 0201 packages was designed to investigate board design and assembly issues. Design of Experiment (DOE) was utilized, using the test vehicle, to explore the influence of key parameters in pad design, printing, pick-andplace, and reflow on the assembly process. These key parameters include printing parameters, mounting height or placement pressure, reflow ramping rate, soak time and peak temperature. The pad designs consist of rectangular pad shape, round pad shape and home-based pad shape. For each pad design, several different aperture openings on the stencil were included. The performance parameters from this experiment include solder paste height, solder paste volume and the number of post-reflow defects. By analyzing the DOE results, optimized pad designs and assembly process parameters were determined.
Technical Library | 2021-05-06 13:41:55.0
Quality control is of vital importance during electronics production. As the methods of producing electronic circuits improve, there is an increasing chance of solder defects during assembling the printed circuit board (PCB). Many technologies have been incorporated for inspecting failed soldering, such as X-ray imaging, optical imaging, and thermal imaging. With some advanced algorithms, the new technologies are expected to control the production quality based on the digital images. However, current algorithms sometimes are not accurate enough to meet the quality control. Specialists are needed to do a follow-up checking. For automated X-ray inspection, joint of interest on the X-ray image is located by region of interest (ROI) and inspected by some algorithms. Some incorrect ROIs deteriorate the inspection algorithm.
Technical Library | 2017-06-01 17:12:08.0
The corrosion of Nickel-Palladium-Gold (Ni-Pd-Au) finish terminals in humid environments is known to be reduced with the application of a conformal coating such as acrylic. Corrosion has a higher rate of occurrence around the terminal ‘knee’ of a surface mount component, which may be reduced with the application of conformal coatings. Although radio frequency (RF) plasma processing is generally known to enhance conformity of conformal coating to surfaces through ionic bombardment, the effect on the functionality of assembled printed circuit boards (PCB) is not as well known. The purpose of this study is to assess whether RF plasma processing can enhance the adhesive and coverage qualities of an acrylic conformal coating on PCBs, specifically on Ni-Pd-Au terminals with a knee, and if plasma processing has an effect on the electrical functionality of components and fully assembled PCB.
Technical Library | 2022-03-16 19:41:17.0
Creep corrosion occurs in electronics assemblies and it is reminiscent to electromigration but does not require electrical field to drive the reaction. Corrosive elements and moisture must be present for creep corrosion to occur. Sulfur is the most prominent element to cause creep corrosion in environments such as paper mills, rubber manufacturing, mining, cement manufacturing, waste water treatment etc., also including companies and locations nearby such industries. The main part of printed circuit board assembly (PCBA) to be affected is the PCB surface finish. Especially immersion silver is prone to creep corrosion, but it sometimes occurs in NiPd (lead frames), and to a lesser extent in ENIG and OSP surface finishes. As the use of immersion silver is increasing as PCB surface finish and electronics are more and more used in harsh environments, creep corrosion is a growing risk. In this paper we will present the driving forces and mechanisms as well as suitable tests and mitigation strategies against creep corrosion
Technical Library | 2012-11-15 23:38:50.0
First published in the 2012 IPC APEX EXPO technical conference proceedings. As we progress in the 21st century, electronics manufacturing will need more and more precision. Parts will get more complex since more components have to be assembled in smaller spaces. Circuit boards and other electronic assemblies will become more densely populated; spacings between components will be shorter. This will require precision manufacturing and efficient cleaning during and post manufacturing. In addition, with population and technology progressing, larger amount of greenhouse gases will be emitted resulting in higher global warming. Intense research effort is going on to develop new generation of chemicals to address both cleaning and global warming issues. Low global warming solutions in refrigeration and as insulating agents are already in the marketplace.
Technical Library | 2014-09-18 16:48:26.0
Two major drivers in electronic industry are electrical and mechanical miniaturization. Both induce major changes in the material selection as well as in the design. Nevertheless, the mechanical and thermal reliability of a Printed Circuit Board (PCB) has to remain at the same high level or even increase (e.g. multiple lead-free soldering). To achieve these reliability targets, extensive testing has to be done with bare PCB as well as assembled PCB. These tests are time consuming and cost intensive. The PCBs have to be produced, assembled, tested and finally a detailed failure analysis is required to be performed.This paper examines the development of our concept and has the potential to enable the prediction of the lifetime of the PCB using accelerated testing methods and finite element simulations.
Technical Library | 2015-07-21 13:50:37.0
Achieving an even coat at the right desired thickness is a major challenge when it comes to applying conformal coating to a Printed Circuit Board (PCB). Applying a coating too thin will ultimately render the electronic assembly vulnerable to potential environmental risks therefore defeating the purpose of the coating. Apply the coat too thick, and it could leave the electronic specific components non-functional therefore destroying the electronic assembly entirely. Coating thickness must meet quality specifications. Measurements for coating thickness may be taken while film is dry or wet. Once measurements are recorded, thickness is compared to quality specifications and fluid dispensing automation machinery is calibrated as necessary. There are a handful of methods for measuring conformal coating thickness that are commonly used in the Electronic Manufacturing Services (EMS) and Original Electronic Manufacturer (OEM) industries. A few commonly used methods for checking conformal coating thickness include:
Technical Library | 2015-09-17 17:36:56.0
RoHS legislated restrictions on the materials used in electronics manufacture have imparted significant challenges on the electronics industry since their introduction in 2006. The greatest impacts have been felt by the mandated elimination of lead from electronic solder followed by the demand for the elimination of haloids from flame retardants used in traditional PCB laminates. In the years which have followed the electronics industry has been beset with a host of new challenges in its effort to comply. Failure mechanisms, both new and old, have surfaced which demand solution and the industry suppliers and manufacturing technologists have worked diligently to remedy those vexing faults through the development of a wide range of new materials and equipment for both board manufacture and assembly, along with modifications to the processes used in the manufacture and assembly of printed circuit boards.
Technical Library | 2018-03-15 07:23:35.0
The SMT assembly process is continuously challenged by the factors which enhance circuit board performance and limit productivity. The pick and place and reflow systems reflect these driven issues by adding more and more controls to their systems, but the fact is one of the age old processes continues to operate within the same rules since the dawn of the SMT assembly world: The SMT screen printing. (...)This paper showcases a new stencil process that was discovered by reverting to the basics:understanding the reason for each stencil material process, focusing on detailed finishes and a disciplined aperture design process, maintaining original designs, and making the correctly designed apertures to control the paste deposition. The test results drove us to focus the efforts on the aperture walls In this paper we will demonstrate with lab tests SMT process results howthe improved paste release results in improved SMT print process performance and its positive impact on SPI yields and EOL performance.
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.
Hitechpcba is a wоrld-lеаding PCB Manufacturing & PCB Assembly company with more than 20 years experience in the electronics manufacturing industry. We focus on Circuit board fabrication, PCB assembly, electronic parts sourcing.
3F, B5 Dong, Zhimeihuizhi, FuYong, Bao'an Dist.
Shenzhen, China
Phone: 008675529630063
