Technical Library | 2018-02-14 22:58:54.0
This document describes general guidelines and attention points for PCB design regarding selective soldering. The guidelines can be applied for Select Wave and/or Multi Wave soldering process in both leaded and leadfree alloy. When a PCB is designed according to these guidelines, a stable and solid solder-process can be guaranteed.
Technical Library | 1999-04-29 15:39:03.0
The paper describes the effects of a debridging knife on inerted soldering environments in an Electrovert Econopak wave solder machine. It reviews experiments to improve the purity of the soldering environment and results of the tests.
Technical Library | 2017-09-14 01:21:52.0
The electronics industry is experiencing a renaissance in semiconductor package technology. A growing number of innovative 3D package assembly methodologies have evolved to enable the electronics industry to maximize their products functionality. By integrating multiple die elements within a single package outline, product boards can be made significantly smaller than their forerunners and the shorter interconnect resulting from this effort has contributed to improving both electrical performance and functional capability. (...) This paper outlines both positive and negative aspects of current 3D package innovations and addresses the challenges facing adopters of silicon and glass based interposer fabrication. The material presented will also reference 3D packaging standards and recognize innovative technologies from a number of industry sources, roadmaps and market forecasts.
Technical Library | 2021-11-03 16:49:59.0
Ultrathin bare die chips were soldered using a novel soldering technology. Using homogeneous flash light generated by high-power xenon flash lamp the dummy components and the bare die NFC chips were successfully soldered to copper tracks on polyimide (PI) and polyethylene terephthalate (PET) flex foils by using industry standard Sn-Ag-Cu lead free alloys. Due to the selectivity of light absorption, a limited temperature increase was observed in the PET substrates while the chip and copper tracks were rapidly heated to a temperatures above the solder melting temperature. This allowed to successfully soldered components onto the delicate polyethylene foil substrates using lead-free alloys with liquidus temperatures above 200 °C. It was shown that by preheating components above the decomposition temperature of solder paste flux with a set of short low intensity pulses the processing window could be significantly extended compared to the process with direct illumination of chips with high intensity flash pulse. Furthermore, it was demonstrated that with localized tuning of pulse intensity components having different heat capacity could be simultaneously soldered using a single flash pulse.
Technical Library | 2013-01-30 14:02:44.0
Many OEM’s require that individual wires and cables used in their products be clearly identified with a mark or label. For some, such as in the military and aerospace markets, wire and cable identification (or “wire ID”) is mandatory and the process is governed by stringent specifications, such as SAE AS50881 (formerly MIL5088L). For others, the decision to use wire ID is a voluntary one. This article will describe what type of information is typically identified on wire and cables, concepts for improved productivity, what types of systems are available and the pros and cons of each.
Technical Library | 2007-10-10 23:23:40.0
Process engineers, who are seeking to achieve the most effective and reproducible thermal transfer process, look to today's forced convection ovens for applications such as flipchip, BGA, and lead-free soldering. A forced convection process to maximize thermal uniformity can be best accomplished by employing static pressure generation in what's known as "closed loop convection".
Technical Library | 2013-08-07 21:52:15.0
PCB architectures have continued their steep trend toward greater complexities and higher component densities. For quality control managers and test technicians, the consequence is significant. Their ability to electrically test these products is compounded with each new generation. Probe access to high density boards loaded with micro BGAs using a conventional in-circuit (bed-of-nails) test system is greatly reduced. The challenges and complexity of creating a comprehensive functional test program have all but assured that functional test will not fill the widening gap. This explains why sales of automated-optical and automated X-ray inspection (AOI and AXI) equipment have dramatically risen...
Technical Library | 2015-01-08 17:26:59.0
Regardless of the accelerating trend for design and conversion to Pb-free manufacturing, many high reliability electronic equipment producers continue to manufacture and support tin-lead (SnPb) electronic products. Certain high reliability electronic products from the telecommunication, military, and medical sectors manufacture using SnPb solder assembly and remain in compliance with the RoHS Directive (restriction on certain hazardous substances) by invoking the European Union Pb-in-solder exemption. Sustaining SnPb manufacturing has become more challenging because the global component supply chain is converting rapidly to Pb-free offerings and has a decreasing motivation to continue producing SnPb product for the low-volume, high reliability end users. Availability of critical, larger SnPb BGA components is a growing concern
Technical Library | 2015-02-27 17:06:01.0
The drive towards fine pitch technology also affects the soldering processes. Selective soldering is a reliable soldering process for THT (through hole) connectors and offers a wide process window for designers. THT connectors can be soldered on the top and bottom side of boards, board in board, PCBs to metal shields or housing out of plastic or aluminum are today's state of the art. The materials that are used to make the solder connections require higher temperatures. Due to the introduction of lead-free alloys, the boards need more heat to get the barrels filled with solder. This not only affects the properties of the flux and components, but the operation temperatures of solder machines become higher (...)First the impact of temperature will be discussed for the separate process steps and for machine tooling. In the experimental part measurements are done to verify the accuracy that can be achieved using today's selective soldering machines. Dedicated tooling is designed to achieve special requirements with respect to component position accuracy.
Technical Library | 2021-09-29 13:35:21.0
In PCB circuit assemblies the trend is moving to more SMD components with finer pitch connections. The majority of the assemblies still have a small amount of through hole (THT) components. Some of them can't withstand high reflow temperatures, while others are there because of their mechanical robustness. In automotive applications these THT components are also present. Many products for cars, including steering units, radio and navigation, and air compressors also use THT technology to connect board-to-board, PCB's to metal shields or housings out of plastic or even aluminium. This is not a simple 2D plain soldering technology, as it requires handling, efficient thermal heating and handling of heavy (up to 10 kg) parts. Soldering technology becomes more 3D where connections have to be made on different levels. For this technology robots using solder wire fail because of the spattering of the flux in the wires and the long cycle time. In wave soldering using pallets the wave height is limited and pin in paste reflow is only a 2D application with space limitations. Selective soldering using dedicated plates with nozzles on the solder area is the preferred way to make these connections. All joints can be soldered in one dip resulting in short cycle times. Additional soldering on a small select nozzle can make the system even more flexible. The soldering can only be successful when there is enough thermal heat in the assembly before the solder touches the board. A forced convection preheat is a must for many applications to bring enough heat into the metal and board materials. The challenge in a dip soldering process is to get a sufficient hole fill without bridging and minimize the number of solder balls. A new cover was designed to improve the nitrogen environment. Reducing oxygen levels benefits the wetting, but increases the risk for solder balling. Previous investigations showed that solder balling can be minimized by selecting proper materials for solder resist and flux.
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