Electronics Forum | Thu Jul 05 21:42:28 EDT 2001 | davef
Most of our boards are fabricated with solder mask over bare copper [SMOBC], but we have couple where the solder isn't removed before masking. And ever so offin they's a liddy bit mo' solder than we'd like, which when reflowed, ends-up connecting so
Electronics Forum | Tue Oct 19 19:25:40 EDT 1999 | Jeff Sanchez
Carol, I think the guys are right about you stand off problem but I want to address the wrinkleing of your masking. Although I think the temps you are subjecting the board to are very high and more than likely creating problems of their own. I th
Industry News | 2010-04-10 02:09:54.0
If a picture is worth a thousand words, the new H revision of IPC-A-600, Acceptability of Printed Boards, is a priceless work of art for fabricators and assemblers, particularly inspectors and product developers. IPC — Association Connecting Electronics Industries® announces the new releases of IPC-A-600H and its companion document the C revision of IPC-6012, Qualification and Performance Specification for Rigid Printed Boards.
Industry News | 2018-03-24 09:45:36.0
Dendrite failure on printed circuit board assemblies is quite common but often not investigated fully to pin point the root cause. This is due to the intermittent nature of the failure or just replacing components seems to solve the problem Book at https://www.bobwillis.co.uk/event/dendrite-failure-causes-cures/
Technical Library | 2008-04-08 17:42:27.0
Concern about the failure of lead-free BGA packages when portable devices such as cell phones are accidentally dropped and a general concern about the resistance of these packages under shock loading has prompted an interest in the impact strength of the soldered BGA connection. This paper reports the results of the measurement of the impact strength of lead-free 0.5±0.01mm diameter BGA spheres on 0.42mm solder mask defined pads on copper/OSP and ENIG substrates using recently developed equipment that can load individual BGA spheres at high strain rates in shear and tension.
Technical Library | 2019-09-24 15:41:53.0
This paper focuses on three different coating material groups which were formulated to operate under high thermal stress and are applied at printed circuit board manufacturing level. While used for principally different applications, these coatings have in common that they can be key to a successful thermal management concept especially in e-mobility and lighting applications. The coatings consist of: Specialty (green transparent) liquid photoimageable solder masks (LPiSM) compatible with long-term thermal storage/stress in excess of 150°C. Combined with the appropriate high-temperature base material, and along with a suitable copper pre-treatment, these solder resists are capable of fulfilling higher thermal demands. In this context, long-term storage tests as well as temperature cycling tests were conducted. Moreover, the effect of various Cu pre-treatment methods on the adhesion of the solder masks was examined following 150, 175 and 200°C ageing processes. For this purpose, test panels were conditioned for 2000 hours at the respective temperatures and were submitted to a cross-cut test every 500 h. Within this test set-up, it was found that a multi-level chemical pre-treatment gives significantly better adhesion results, in particular at 175°C and 200°C, compared with a pre-treatment by brush or pumice brush. Also, breakdown voltage as well as tracking resistance were investigated. For an application in LED technology, the light reflectivity and white colour stability of the printed circuit board are of major importance, especially when high-power LEDs are used which can generate larger amounts of heat. For this reason, a very high coverage power and an intense white colour with high reflectivity values are essential for white solder masks. These "ultra-white" and largely non-yellowing LPiSM need to be able to withstand specific thermal loads, especially in combination with high-power LED lighting applications. The topic of thermal performance of coatings for electronics will also be discussed in view of printed heatsink paste (HSP) and thermal interface paste (TIP) coatings which are used for a growing number of applications. They are processed at the printed circuit board manufacturing level for thermal-coupling and heat-spreading purposes in various thermal management-sensitive fields, especially in the automotive and LED lighting industries. Besides giving an overview of the principle functionality, it will be discussed what makes these ceramic-filled epoxy- or silicone-based materials special compared to using "thermal greases" and "thermal pads" for heat dissipation purposes.
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ASYMTEK Products | Nordson Electronics Solutions | https://www.nordson.com/en/divisions/efd/resource-center/solder-glossary-of-terms
. Compacting during solder paste dispensing, can be observed in the dispense tip and all other sections of the flow path. Copper Mirror Test IPC–TM-650 2.3.32
| https://www.eptac.com/wp-content/uploads/2021/10/EPTAC_DataSheet_IPCDesigner_CID.pdf
• Component Insertion & Attachment Techniques • Solder Processes • Clinched Leads BOARD SURFACE TREATMENTS • Solder Mask, Conformal Coatings, Protective Coatings/Surface Finishes • Legend
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