Technical Library | 2023-01-17 17:27:13.0
Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The degree of wetting, the microstructure (in particular the intermetallic layer), and the inherent strength of the solder all factor into the reliability of the solder joint. This paper presents experimental results on the effect of reflow profile on both 63%Sn 37%Pb (SnPb) and 96.5%Sn 3.0%Ag 0.5%Cu (SAC 305) solder joint shear force. Specifically, the effect of the reflow peak temperature and time above solder liquidus temperature are studied. Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb have been developed with three levels of peak temperature (230 o C, 240 o C, and 250 o C for SAC 305; and 195 o C, 205 o C, and 215 o C for SnPb) and three levels of time above solder liquidus temperature (30 sec., 60 sec., and 90 sec.). The shear force data of four different sizes of chip resistors (1206, 0805, 0603, and 0402) are compared across the different profiles. The shear force of the resistors is measured at time 0 (right after assembly). The fracture surfaces have been studied using a scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS)
Technical Library | 2014-09-11 11:47:39.0
This article goes through the pluses and minuses of using plastic stencils for DIY prototypes. The release efficiency is measured and "rules of thumb" for using one type vs another is explained.
Technical Library | 2007-02-01 09:27:47.0
The purpose of the testing was to compare the resistance and check for open circuit conditions of reworked BGA test samples made with and without StencilQuik™ after 500 thermal shock cycles. StencilQuick™ is a product of Best Inc. In this series of tests, the resistance of daisy chain resistance patterns running between the BGA and test board after exposure to thermal shock was measured.
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 | 2013-05-30 17:33:26.0
This paper covers the following topics: The Measurement Application, Measurement Requirements, Measurement Problems, Measurement Results, Reference Samples, Conclusions
Technical Library | 2013-10-13 10:54:13.0
The measurement of the conformal coating thickness on a printed circuit board (PCB) to ensure internal and international standards are met is now a critical factor in conformal coating process control. There are several methods for measurement of conformal coating thickness and they fall into two categories. These categories are wet film measurements applied during coating application and dry film measurements made after the coating is dried enough not to damage the coating.
Technical Library | 2016-08-23 06:16:35.0
While many things can affect the force measurement accuracy of a bond test, its ultimate limitation is that of the force sensor. With advances in technology, accuracy can be dramatically improved with no cost penalty and no need to select force measurement ranges. How is this accomplished?
Technical Library | 2013-01-31 18:43:15.0
There are three key industry trends that are driving the need for temperature-dependent warpage measurement: the trend toward finer-pitch devices, the emergence of lead-free processing, and changes in device form factors. Warpage measurement has become a key measurement for analysis; prevention and prediction of interconnect defects and has been employed in failure analysis labs and production sites worldwide. First published in the 2012 IPC APEX EXPO technical conference proceedings
Technical Library | 2001-05-23 16:29:52.0
Management consultant R. Michael Donovan outlines the problems and opportunities of performance measurement as an "enabling force" for improving overall business performance...
Technical Library | 2015-04-29 03:48:39.0
SPI equipment is routinely used in Printed Circuit Board (PCB) manufacturing to monitor and control one of the most crucial steps affecting the finished quality of circuit board. Solder paste deposition is the key process in board assembly operations using SMT techniques. Our LSM™ system was the industry's first popular method of manually inspecting solder paste; our SE systems revolutionized SMT production by offering an automated method for performing in-process 3D inspection on the assembly line. SPI systems measure the height and volume of the solder pads before the components are applied and the solder melted, and when used properly, can reduce the incidence of solder-related defects to statistically insignificant amounts. Critical to the SPI measurement is the accuracy of the height measurement because that has a direct correlation with solder volume and defects.
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