Technical Library | 2023-08-16 18:09:06.0
One of our customers involved with Electronics and Aerostructures requested a test to dispense Techspray Wondermask 2204 solder mask. The dispensing locations include large and small screw holes, single through-hole vias, and connector locations consisting of multiple through-hole vias. The process needed to run quickly and reliably.
Technical Library | 2007-02-01 10:08:40.0
The increased replacement of high lead count SMT devices with BGAs and other high ball count area array packages has brought increased challenges to PCB rework and repair. Often solder mask areas surrounding BGA pad areas are damaged when components are removed.
Technical Library | 2019-05-29 01:47:22.0
1.Vias near SMD pads: Solder can flow into the via after melted. As a result cold joint will appear in the end. Check the picture below. 2.Vias on SMD pads: Solder can flow into the via more easier after melted. Check the picture below. 3.Via opening without soldermask covered. When workers solder TH parts by hand, soldering iron can touch vias sometime, then tiny amounts molten solder will stay on vias. This can lead to electrical short easily. We recommend you make all vias tenting (covered by solder mask) if it is possible.
PCBNPI-Professional PCB Fab/PCB Assembly Service Provider From China
Technical Library | 2019-10-10 00:26:28.0
Voids are a plague to our electronics and must be eliminated! Over the last few years we have studied voiding in solder joints and published three technical papers on methods to "Fill the Void." This paper is part four of this series. The focus of this work is to mitigate voids for via in pad circuit board designs. Via holes in Quad Flat No-Lead (QFN) thermal pads create voiding issues. Gasses can come out of via holes and rise into the solder joint creating voids. Solder can also flow down into the via holes creating gaps in the solder joint. One method of preventing this is via plugging. Via holes can be plugged, capped, or left open. These via plugging options were compared and contrasted to each other with respect to voiding. Another method of minimizing voiding is through solder paste stencil design. Solder paste can be printed around the via holes with gas escape routes. This prevents gasses from via holes from being trapped in the solder joint. Several stencil designs were tested and voiding performance compared and contrasted. In many cases voiding will be reduced only if a combination of mitigation strategies are used. Recommendations for combinations of via hole plugging and stencil design are given. The aim of this paper is to help the reader to "Fill the Void."
Technical Library | 2023-06-12 19:18:24.0
As any new technology emerges, increasing levels of refinement are required to facilitate the mainstream implementation and continual improvement processes. In the case of lead-free processing, the initial hurdles of alloy and chemistry selection are cleared on the first level, providing a base process. The understanding gained from early work on the base process leads to the next level of refinement in optimizing the primary factors that influence yield. These factors may include thermal profiles, PWB surface finishes, component metallization, solder mask selection or stencil design.
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 | 2010-03-18 14:02:03.0
Selecting products that have been qualified by industry standards for use in printed circuit board assembly processes is an accepted best practice. That products which have been qualified, when used in combinations not specifically qualified, may have resultant properties detrimental to assembly function though, is often not adequately understood. Printed circuit boards, solder masks, soldering materials (flux, paste, cored wire, rework flux, paste flux, etc.), adhesives, and inks, when qualified per industry standards, are qualified using very specific test methods which may not adequately mimic the assembly process ultimately used.
Technical Library | 1999-07-21 09:04:04.0
A high volume manufacturer of printed circuit boards (PCBs) had attempted for many years to locate an adhesive that was robust enough to meet their manufacturing needs. This proved to be a challenge because they needed the adhesive to accommodate a wide range of different dispensing equipment and board designs. The two key performance criteria required from the adhesive were dispensability and adhesion...
Technical Library | 2024-07-24 01:18:03.0
Quad Flat No-Lead (QFN) packages has become very popular in the industry and are widely used in many products. These packages have different size and pin counts, but they have a common feature: thermal pad at the bottom of device. The thermal pad of the leadless QFN provides efficient heat dissipation from the component to PCB. In many cases, arrays of the thermal via under the component is used to dissipate heat from the device. However, thermal vias can create more voids or result in solder protrusion onto the secondary side.
Technical Library | 2019-01-02 21:51:49.0
Failed solder joints remain a constant source of printed circuit board failure. Soldering is the bonding of metallic surfaces via an intermetallic compound (IMC). The interaction between thermal energy delivery, flux chemistry, and solder chemistry creates the solder bond or joint. Today, reliability relies on visual inspection; operator experience and skill, control of influencers e.g. tip geometry, tip temperature, and collection and analysis of process data. Each factor involved with the formation of the solder joint is an element of risk and can affect either throughput or repeatability. Mitigating this risk in hand soldering requires the identification of these factors and a means to address them.
.gif)