Technical Library | 2019-06-07 14:49:54.0
ACI Technologies was contacted in regards to poor solder joint reliability. The customer submitted an assembly that was exhibiting intermittent opens at multiple locations on a ball grid array (BGA) component. The assembly’s functionality did not survive international shipping, essentially shock and vibration failures, immediately making the quality of the solder joints suspect. The customer was asked about the contract manufacturer and the reflow oven profile as well as the solder paste and surface finish used. The ACI engineering staff evaluated the contract manufacturer’s technique and determined that they were competent in the methods they used for placing thermocouples in the proper locations and developing the reflow oven profile. The surface finish was unusual, but not unheard of, in that it was hard gold over hard nickel, rather than electroless nickel immersion gold (ENIG). The customer was able to supply boundary scan testing data which showed a diagonal row of troublesome BGA pins.
Technical Library | 2019-05-29 23:10:30.0
There are times when a PCB prototype needs to be built quickly to test out a design. In such cases where it is known early on that there will be multiple iterations or that a "one and done" assembly will be made that there will be some SMT assemblers who choose to hand print solder paste onto the board using a "frameless" stencil. In such cases where hand printing is used, the consistency of the printing technique has typically been in question. Furthermore, the effectiveness of both the nanocoatings as well as the higher end stainless steel materials, which have been heretofore studied in controlled printing environments, will be evaluated for their impact on the hand printing process.The purpose of the study was to determine the effectiveness of select nanocoating materials as well as certain high end stainless steel stencil materials as they relate to the manual SMT printing process. A variety of nanocoatings were applied to SMT metal stencils and solder paste volume measurements were taken to compare the effectiveness.
Technical Library | 2022-04-29 00:49:12.0
Tools: soldering iron, soldering iron stand, wet sponge, tweezers, rosin, solder, absorbent cotton, 95% alcohol, chip resistors, capacitors, circuit boards, 220V power supply..... http://www.leadersmt.com/gen2/1028113523/?mod=file&col_key=download
Technical Library | 2013-01-05 22:21:01.0
More and more countries legislate to forbib lead usage in solder material. However, the lead-free solder wire has higher melting point and soldering temperature, increase soldering iron temperature may damage the PCB or components. How to solve this problem?
Technical Library | 2019-11-07 08:59:14.0
Inductors realized with high permeable MnZn ferrite require, unlike iron-powder cores with an inherent dis-tributed gap, a discrete air gap in the magnetic circuit to prevent saturation of the core material and/or tune the inductance value. This large discrete gap can be divided into several partial gaps in order to reduce the air gap stray field and consequently the proximity losses in the winding. The multi-gap core, realized by stacking several thin ferrite plates and inserting a non-magnetic spacer material between the plates, however, exhibits a substan-tial increase in core losses which cannot be explained from the intrinsic properties of the ferrite. In this paper, a comprehensive overview of the scientific literature regarding machining induced core losses in ferrite, dating back to the early 1970s, is provided which suggests that the observed excess core losses could be attributed to a deterioration of ferrite properties in the surface layer of the plates caused by mechanical stress exerted during machining.
Technical Library | 2014-03-06 19:04:07.0
Over the last few years, there has been an increase in the rate of Head-in-Pillow component soldering defects which interrupts the merger of the BGA/CSP component solder spheres with the molten solder paste during reflow. The issue has occurred across a broad segment of industries including consumer, telecom and military. There are many reasons for this issue such as warpage issues of the component or board, ball co-planarity issues for BGA/CSP components and non-wetting of the component based on contamination or excessive oxidation of the component coating. The issue has been found to occur not only on lead-free soldered assemblies where the increased soldering temperatures may give rise to increase component/board warpage but also on tin-lead soldered assemblies.
Technical Library | 2011-03-30 21:14:33.0
The expression "multifunctional PCB", as a synonym for a PCB which is applicable with a variety of assembly techniques, is already established on the market. That means the PCB can be used for multiple reflow soldering and multiple assembly techniques lik
Technical Library | 2013-03-27 23:43:40.0
Vapor phase, once cast to the annals’ of history is making a comeback. Why? Reflow technology is well developed and has served the industry for many years, it is simple and it is consistent. All points are true – when dealing with the centre section of the bell curve. Today’s PCB manufacturers are faced with many designs which no longer fall into that polite category but rather test the process engineering groups with heavier and larger panels, large ground planes located in tricky places, component mass densities which are poorly distributed, ever changing Pb Free alloys and higher process temperatures. All the time the costs for the panels increase, availability of “process trial” boards diminishes and yields are expected to be extremely high with zero scrap rates. The final process in the assembly line has the capacity to secure all the value of the assembly or destroy it. If a panel is poorly soldered due to poor Oven setup or incorrect programming of the profile the recovery of the panel is at best expensive, at worst a loss. For these challenges people are turning to Vapor Phase.
Technical Library | 2017-11-10 00:58:37.0
Modern electronics manufacturing is made up by a multiplicity of different separation and joining processes, with the later surely taking the vast majority of production technology. Alongside gluing, welding and laser processes, soldering still holds a primary position in electronic assemblies. However, soldering does not always equal soldering, because there are quite a lot of different soldering technologies. Accordingly, you have to distinguish between automated and manual soldering procedures. No matter which soldering process you analyse, all of them have one aspect in common: they produce airborne pollutants, which may have a negative impact on employees, plants and products as well.
Technical Library | 2020-10-18 19:35:05.0
Interconnect reliability especially in BGA solder joints and compliant pins are subjected to design parameters which are very critical to ensure product performance at pre-defined shipping condition and user environment. Plating thickness of compliant pin and damping mechanism of electronic system design are key successful factors for this purpose. In additional transportation and material handling process of a computer server system will be affected by shock under certain conditions. Many accessories devices in the server computer system tend to become loose resulting in poor contact or solder intermittent interconnect problems due to the shock load from the transportation and material handling processes.
