Technical Library | 2013-07-03 10:31:54.0
It has been demonstrated in numerous pieces of work that stencil printing, one of the most complex PCB assembly processes, is one of the largest contributors to defects (Revelino et el). This complexity extends to prototype builds where a small number of boards need to be assembled quickly and reliably. Stencil printing is becoming increasingly challenging as packages shrink in size, increase in lead count and require closer lead spacing (finer pitch). Prototype SMT assembly can be further divided between industrial and commercial work and the DIYer, hobbyist or researcher groups. This second group is highly price sensitive when it comes to the materials used for the board assembly as their funds are sourced from personal or research monies as opposed to company funds. This has led to development of a lower cost SMT printing stencil made from plastic film as opposed to the more traditional stainless steel stencil used by industrial and commercial users.This study compares the performance of these two traditional materials and their respective impact on solder paste printing including efficiency and print quality.
Technical Library | 2024-11-19 16:18:43.0
What are the factors involved in determining laser cutting costs and what steps can be taken to lower the final costs.
Technical Library | 2020-04-01 23:32:29.0
Low temperature solder alloys are preferred for the assembly of temperature-sensitive components and substrates. The alloys in this category are required to reflow between 170 and 200oC soldering temperatures. Lower soldering temperatures result in lower thermal stresses and defects, such as warping during assembly, and permit use of lower cost substrates. Sn-Bi alloys have lower melting temperatures, but some of its performance drawbacks can be seen as deterrent for its use in electronics devices.Here we show that non-eutectic Sn-Bi alloys can be used to improve these properties and further align them with the electronics industry specific needs. The physical properties and drop shock performance of various alloys are evaluated, and their results are analysed in terms of the alloy composition, including Bi content and alloying additions.
Technical Library | 2018-08-08 21:55:00.0
180 °C and Td >400 °C. In addition to a high thermal stability, Material A also shows a dielectric loss factor lower than commercial phosphorus-based flame retardants.
Technical Library | 2012-12-14 14:25:37.0
The popularity of low voltage technologies has grown significantly over the last decade as semiconductor device manufacturers have moved to satisfy market demands for more powerful products, smaller packaging, and longer battery life. By shrinking the size of the features they etch into semiconductor dice, IC manufacturers achieve lower costs, while improving speed and building in more functionality. However, this move toward smaller features has lead to lower breakdown voltages and increased opportunities for component overstress and false failures during in-circuit test.
Technical Library | 2015-07-01 16:51:43.0
Aerospace and military companies continue to exercise RoHS exemptions and to intensively research the long term attachment reliability of RoHS compliant solders. Their products require higher vibration, drop/shock performance, and combined-environment reliability than the conventional SAC305 alloy provides. The NASA-DoD Lead-Free Electronics Project confirmed that pad cratering is one of the dominant failure modes that occur in various board level reliability tests, especially under dynamic loading. One possible route to improvement of the mechanical and thermo-mechanical properties of solder joints is the use of Pb-free solders with lower process temperatures. Lower temperatures help reduce the possibility of damaging the boards and components, and also may allow for the use of lower Tg board materials which are less prone to pad cratering defects. There are several Sn-Ag-Bi and Sn-Ag-Cu-Bi alloys which melt about 10°C lower than SAC305. The bismuth in these solder compositions not only reduces the melting temperature, but also improves thermo-mechanical behavior. An additional benefit of using Bi-containing solder alloys is the possibility to reduce the propensity to whisker growth
Technical Library | 2010-12-09 20:26:15.0
As demands accelerate for increasing density, higher bandwidths, and lower power, many IC design teams are looking up – to 3D ICs with through-silicon vias (TSVs). 3D ICs promise “more than Moore” integration by packing a great deal of functionality int
Technical Library | 2011-05-05 16:17:34.0
Passives account for a very large part of today’s electronic assemblies. This is particularly true for digital products such as cellular phones, camcorders, and computers. Market pressures for new products with more features, smaller size and lower cost v
Technical Library | 2012-11-12 14:06:48.0
With consumers constantly looking for lower prices on their technology products and manufacturers trying to squeak out higher margins from their production lines, the need for process control and lower overhead costs have become even more important. One sector that is often overlooked is the hand soldering area of the factory. Many factories have been struggling with antiquated soldering systems for years. In some cases they are trying to make their investment in stations last much longer than they were designed for, or they are falsely trying to recoup their original investment ‐ all at the cost of higher operating expenses or even worse, reduced operator thru‐put.
Technical Library | 1999-05-09 13:14:02.0
Studies and tests of comparative soldering iron thermal performance at low temperatures - Metcal direct power soldering technology compared to conventional stored energy soldering irons from leading manufacturers.
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