Browse Topic: Soldering

Items (206)
A temperature dependent cohesive zone model considering the thermo-mechanical fatigue loadings are used to simulate and predict the failure process of solder joint interface in power electronics modules. Cohesive Zone Models (CZMs) are gaining popularity for modeling the fracture and fatigue behavior in various class of materials such as metals, polymers, ceramics, and their composite materials. Unlike the traditional fracture mechanics which considers concept of infinitesimal crack, CZMs assume a fracture process zone in which external energy is distributed in vicinity to propagating crack. In order to predict the fatigue-fracture process under thermo-mechanical cyclic loading, a damage accumulation variable is utilized. The calculation of damage is performed using a progressive mechanism, and the cohesive zone model is updated to reflect the present level of damage. The existing cohesive forces are influenced by both the current damage status and the extent of separation
Singh, Praveen KumarSahu, AbhishekChirravuri, BhaskaraMiller, Ronald
ABSTRACT Lower cost aluminum silicon carbide (Al-SiC) metal matrix composite (MMC) produced by stir-casting is emerging as an important material in cost effectively improving the reliability of high power electronic devices; e.g. electronic (IGBT) baseplates, thermal spreaders & stiffeners for flip-chip microelectronics, and heat slugs or MCPCB base layers for high brightness LEDs. This paper will review the properties and competitive cost of these new Al-SiC materials as well as the ability to tailor the coefficient of thermal expansion (CTE) of the Al-SiC to minimize thermal fatigue on solder joints and reduce component distortion. The impact on the final component cost through the use of conventional forming techniques such as (a) rolling sheet followed by stamping, and, (b) die casting, will be described, as will be the opportunity of eliminating a thermal interface material (TIM) layer by integrating the thermal spreader with the heat sink for high power microelectronic packages
Drake, AllenSchuster, DavidSkibo, Michael
EVs are a fast-growing market and appear as a promising option against the high emission of gasoline and diesel vehicles. The growth in the EV market has been decent and a regular buyer is still skeptical due to fire incidents occurring with EVs. Complex electronics, improper thermal management, mechanical abuse, improper cell grading activities and control in production, lack of testing in a production plant, and of course, uneven degradation of cells can be one of the reasons this promising technology is facing thermal runaway and in turn, the wrath of the government and public alike. One of the reasons thermal runaways can be triggered after a cell catches fire is because a part of heat travels via busbars to the neighboring cells, as the busbars can conduct heat faster than the air. For the heat that is conducted, it is easily understandable that we need to break the electrical, as well as thermal conduction connection to the neighboring cells. This paper presents a comparison of
Pawar, AniruddhaKhan, FaizShah, HarshMalani, Shekhar
This technical report identifies the requirements for an LFCP for ADHP soldered electronic products built fully or partially with Pb-free materials and assembly processes. An LFCP documents the specific Pb-free materials and assembly processes used to assure customers their ADHP soldered electronic products will meet the applicable reliability requirements of the customer. This standard specifically addresses LFCPs for: a Pb-free components and mixed assembly: Products originally designed and qualified with SnPb solder and assembly processes that incorporate components with Pb-free termination finishes and/or Pb-free BGAs, i.e., assembling Pb-free parts using eutectic/near-eutectic SnPb processes (also known as mixed metallurgy). b COTS products: COTS products likely built with Pb-free materials and assembly processes. c Pb-free design and assembly: Products designed and qualified with Pb-free solder and assembly processes. This standard does not include detailed descriptions of the
G-24 Pb-free Risk Management Committee for ADHP
Requirements for high-reliability lead-free solder alloys in automotive electronics are becoming more challenging as assembly designs require increased powder densities and miniaturization in combination with harsh operating conditions. Thermal cycling performance has been the primary factor for deciding on the suitability of a solder alloy for such applications. Solder joint reliability under thermal and mechanical stresses depends on the solder, packages, PCB, and assembly, including global and local CTE mismatch. Automotive electronic assemblies for critical applications commonly require operational temperatures around 150oC, while soldering temperatures need to be as low as possible (<250oC). To resolve performance gaps in Sn-Ag-Cu solders for such applications, alloying additives can be used for: i) lowering the melting temperature, ii) improving creep properties, and iii) improving fatigue life. This is exemplified here by comparing a high reliability alloy, commonly known as
Choudhury, PrithaKumar, AnilAugustine, PrathapKosuri, DivyaSarkar, SiuliSalerno, PaulRibas, Morgana
This specification covers the requirements for electrodeposited tin-lead plating intended for use as a coating for corrosion protection and as a base for soldering
AMS B Finishes Processes and Fluids Committee
This specification covers three series of environment resisting, circular, miniature electrical connectors (plugs and receptacles) with removable crimp and/or nonremovable solder contacts, and accessories. The connectors are only recommended for replacement and are not specified for aircraft applications (refer to AS50881
AE-8C1 Connectors Committee
Rosin is a naturally available organic material obtained especially from pine trees. It finds many usages and applications in areas like soldering, pharmaceuticals, building work, engineering field etc. In this work, an attempt has been made to study experimentally the improvement in strength of rosin at normal stove top temperature by means of combining rosin in various ratios with some important organic hardeners and chemicals of literature importance. A table top book press was fabricated for the purpose of rosin pressing using simple tools like teak wood, bolt and nuts. Experiments were conducted using commonly used kitchen gas stove, fabricated book press, rosin raw material, aluminium sulfate powder, maleic anhydride chemical, acetone, ethanol and saw dust particles for making different combination materials using rosin as the main element. Results showed that, rosin on its own without additives showed higher viscosity and brittleness. When combined with organic hardener
Kumar Ayyaswamy, John PresinS., SivakumarS., SathishRavikumar Solomon, Gnanadurai
Reliability states the degree to which the result of a measurement, calculation, or specification can be depended on to be accurate. And, tests according to GM specifications represents a minimum of 15 years of vehicle life time with defined Reliability and Confidence level. In this work, actual number of thermal cycles for Thermal Fatigue tests (Thermal Shock and Power Temperature Cycle) are calculated for Copper Wire whose Coffin Manson exponent is 5. Overstressing the PEPS Antenna under thermal fatigue requirement (defined number of thermal cycles based on Reliability and Confidence requirements) will lead to broken Copper wire which will result in component’s functional failure and thus impossible to continue reliability testing. The objective of this paper is to determine thermal fatigue requirements for Antenna’s Copper wire whose Coffin Manson exponent is 5. Testing with exact number of thermal cycles will reduce the validation failures owing to broken Copper wire and thus save
Jauhri, Abhinav
Industry consensus developed IPC standards for the automotive electronics manufacturer have been available since 2016. We will look at the current IPC standards available in development and in revision, the standards development process, and the automotive application addendums for printed board fabrication and assembly soldering that provide unique criteria for the reliability of electronic interconnects that must survive the harsh environments within the automotive industry. Attention will be given to a new effort in development to provide links between existing automotive-centric IPC standards and other industry standards applicable to automotive applications for printed board material selection, design, and solder joint reliability testing. We will also discuss challenges facing the industry, including process changes and cleanliness requirements, e.g. ionic contaminants, that affect every manufacturer and customer
Perry, JohnRowe, Teresa
The choice of the type and grade of solder for any specific purpose will depend on the materials to be joined and the method of applying. Those with higher amounts of tin usually wet and bond more readily and have a narrower semi-molten range than lower amounts of tin. For strictly economic reasons, it is recommended that the grade of solder metal be selected that contains least amount of tin required to give suitable flowing and adhesive qualities for application. All the lead-tin solders, with or without antimony, are usually suitable for joining steel and copper base alloys. For galvanized steel or zinc, only Class A solders should be used. Class B solders, containing antimony usually as a substitute for some of the tin or to increase strength and hardness of the filler metal, form intermetallic antimony-zinc compounds, causing the joint to become embrittled. Lead-tin solders are not recommended for joining aluminum, magnesium, or stainless steel. Permissible impurity levels are
Metals Technical Committee
This document applies to the development of Plans for integrating and managing electronic materials and processes for equipment in the military and commercial aerospace markets; as well as other ADHP markets that wish to use this document. Examples of electronic materials and processes, as described in this document, include soldering alloys, plating finishes, bulk metals, chassis materials and finishes, materials used for mechanical parts, etc. It is critical for the Plan owner to review and understand the properties and configuration control of all “as-received” or “off-the-shelf” electronic materials with respect to the application capabilities in order to identify risks, and where necessary, take additional action to mitigate the risks. The technical requirements are in Section 3 of this standard, and the administrative requirements are in Section 4
APMC Avionics Process Management
This specification covers circular threaded electrical connectors with solder or removable crimp contacts (both front and rear release). These connectors are for use in electronic, electrical power, and control circuits (see 6.1
AE-8C1 Connectors Committee
This research proposes a third-generation power control unit (PCU) for a two-motor hybrid system. To make a more compact intelligent power unit (IPU) to be located under the second seat, a PCU with a 12-volt DC-DC converter (DCDC) that mounts directly on the transmission was developed, whereas the DCDC was previously mounted within the IPU. Since this has a considerable impact on the engine room layout, the technology described below was used to make the PCU even more compact than the second-generation unit. The power module, a key component of the PCU, now uses Ag nanoparticles sintering bonding rather than conventional solder bonding. This helps lower thermal resistance and enables smaller power semiconductors. The voltage control unit (VCU) has a new circuit that uses a multi-stage switching circuit and electric power transfer capacitor instead of the conventional chopper circuit. This makes it possible to shrink the reactor to less than 65% of its usual volume without raising the
Ozuchi, YasuhiroTomokage, Ryoji
This document defines: 1 A default method for those companies that require a pre-defined approach and 2 A protocol for those companies that wish to develop their own test methods. The default method (Section 4 of the document) is intended for use by electronic equipment manufacturers, repair facilities, or programs which, for a variety of reasons, may be unable to develop methods specific to their own products and applications. It is to be used when little or no other information is available to define, conduct, and interpret results from reliability, qualification, or other tests for electronic equipment containing Pb-free solder. The default method is intended to be conservative, i.e., it is biased toward minimizing the risk to users of AHP electronic equipment. The protocol (Section 5 of the document) is intended for use by manufacturers or repair facilities which have the necessary resources to design and conduct reliability, qualification, or process development tests that are
G-24 Pb-free Risk Management Committee for ADHP
This specification covers the requirements for preparation of aluminum and aluminum alloys for soldering by zinc immersion pre-treatment followed by copper plating and tin or tin-zinc alloy plating
AMS B Finishes Processes and Fluids Committee
The huge demand for switching components exceeding silicon's (Si) current density limitation of 200 A/cm2 has pushed the enhancement of alternative semiconductor materials such as silicon carbide (SiC), gallium nitride, and diamond. The enhanced material properties of SiC, such as high thermal conductivity, large critical field, wide bandgap, large elastic modulus, and high saturation velocity, make it a viable candidate for pulsed power systems. Using SiC would increase both current and power densities, improve dI/dt and dV/dt capabilities, reduce recovery time, and minimize switching losses in various power electronic systems. Furthermore, a significant reduction in the volume and weight of pulsed power systems can be realized by implementing SiC SGTOs, reducing the thermal management requirements of the pulsed power system
Power modules are used to operate three-phase alternating current motors in hybrid vehicles and electric vehicles. Good fuel efficiency and high power density are required in the field of hybrid vehicles. To achieve this goal, the miniaturization of the power module will be necessary. This trend may make a current density, which is created by insulated gate bipolar transistors (IGBTs) and free wheel diodes (FWDs), higher in power modules. Solder is often used as the joint material of power modules. It is known that a current density larger than 10 kA/cm2 causes solder electromigration. This phenomenon may cause delamination of the joint area. In addition, the ambient temperature has an influence on electromigration. The temperature of an engine compartment is high, so it is likely to cause electromigration. However, the current density of the double-sided cooling power modules in 2007 with solder joint is lower than 0.4 kA/cm2, and this value is lower than 10 kA/cm2. This current
Take, NaoyaKadoguchi, TakuyaNoguchi, MasaoYamanaka, Kimihiro
For the purpose of improving vehicle fuel efficiency, it is necessary to reduce energy loss in the alternator. We have lowered the resistance of the rectifying device and connecting components, and control the rectifying device with an IC to reduce rectification loss. For the package design, we have changed the structure of the part on which the rectifying device is mounted into a high heat dissipation type. The new structure has enabled optimizing the size of the rectifying device, resulting in the reduction of size of the package. In addition, the rectifying device is mounted using a new soldering material and a new process, which has improved the reliability of the connection. Moreover, since the alternator has introduced a new system, the controller IC has a function for preventing malfunction of the rectifying device and a function for detecting abnormalities, in order to ensure safety. These technologies have realized a low-energy loss high-reliability rectifier, which contribute
Matsushita, Koki
This specification covers the general requirements for removable crimp, solderless wrap, and solder type electrical contacts for use in connectors and other electric and electronic components (see 6.1) with stranded conductor wire. The contacts shall be capable of operating within the temperature range as specified (see 3.1
AE-8C1 Connectors Committee
Iowa State engineers have developed micro-sized liquid-metal particles for heat-free soldering and metal processing applications
This document is intended for use as technical guidance by Aerospace system suppliers, e.g., Aerospace system Original Equipment Manufacturers (OEMs) and Aerospace system maintenance facilities, in developing and implementing designs and processes to assure the continued performance, quality, reliability, safety, airworthiness, configuration control, affordability, maintainability, and supportability of high performance aerospace systems (subsequently referred to as AHP) both during and after the transition to Pb-Free electronics. This document is intended for application to aerospace products; however, it may also be applied, at the discretion of the user, to other products with similar characteristics, e.g., low-volume, rugged use environments, high reliability, long lifetime, and reparability. If other industries wish to use this document, they may substitute the name of their industry for the word “Aerospace” in this document. The guidelines may be used by the OEMs and maintenance
G-24 Pb-free Risk Management Committee for ADHP
The use of Micro Electro-Mechanical Systems (MEMS) for measuring accelerations, pressure, gyroscopic yaw rate and humidity in engine controls, inflatable restraint, braking, stability and other safety critical vehicle systems is increasing. Their use in these safety critical systems in high stress automotive environments makes ensuring their reliability and durability essential tasks, especially as the Vehicle System Functional Safety requirements of ISO-26262 are being implemented across the industry. A Design for Reliability (DfR) approach that applies Physics of Failure methods to evaluate and eliminate or mitigate susceptibilities to failure modes of a device during the design of a product is the most effective and efficient way to achieve Functional Safety levels of reliability-durability. MEMS packages exhibit several failure modes that can be predicted as a device is designed using modern Computer Aided Engineering (CAE) software tools. This paper provides a methodology for
Caswell, Greg K.McLeish, James
Northeastern University’s Hanchen Huang, a professor and chair of the Department of Mechanical and Industrial Engineering, and two of his PhD students say they have come up with a better way of sticking things together
Manufacturers of medical devices must seek every way possible to eliminate failures of those devices. Many major failures result from a weakness in the solder joint that connects the wire bond to the printed circuit board (PCB) or the solder connecting the device or package to the board. Using nitrogen is not an absolute requirement. However, among other things, nitrogen can help to strengthen the bond and improve solder adhesion in the soldering process. This article explores the use of nitrogen and ways to minimize device failure
This handbook is designed to assist a program in assuring the performance, reliability, airworthiness, safety, and certifiability of product(s), in accordance with GEIA-STD-0005-1, “Performance Standard for Aerospace and High Performance Electronic Systems Containing Pb-free Solder”. Please note that the program manager, and managers of systems engineering, Supply Chain and Quality Assurance (along with their respective organizations), and the appropriate enterprise authority need to work together in ensuring that all impacts of Pb-free technology insertion are understood and risks mitigated accordingly. Herein “program management (or manager), supplier chain management (or manager), quality assurance management (or manager) and systems engineering management (or manager) and/or the appropriate enterprise authority” shall be defined as “responsible manager” throughout the remaining document (see Section 3, Terms and Definitions). The basic principles delineated in this handbook can be
G-24 Pb-free Risk Management Committee for ADHP
For many years, stencil printing has been the standard method of depositing solder paste on surface mount assembly printed circuit boards (PCBs). It has provided a durable method of applying solder paste, but there were always difficulties that significantly slowed down a change from one product to another in the assembly operation, and added cost. A significant challenge in newer, smaller electronics assembly is the huge difference in size among components. Therefore, trying to apply the right amount of solder paste for each component with one stencil is difficult. The biggest problem is how to produce quick-turn prototypes without disrupting series production that is already running in the line. Product changeover requires time-consuming tweaks to the stencil printing process, while unnecessarily shutting down an expensive assembly line to change the product. The inability of the stencil’s technology to vary solder paste volume by part, on the run, remains the biggest impact on the
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