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 | 2026-03-17 20:56:28.0
Color quantization is an image processing operation that attempts to reduce the number of distinct colors used to represent an image without significant loss of quality. This operation is useful as an initial step to perform further processing on the image. The interest in this operation has led to several solution methods being proposed over the years. Within these methods several swarm-based methods have been used in recent years to solve the problem. This article discusses the application of one of these methods, called grey wolf optimization, to perform color quantization. This algorithm has generated good results when applied to a variety of optimization problems. Among the features that differentiate this algorithm from other swarm algorithms are its ability to converge toward better solutions, its speed, and the existence of a single control parameter. The article describes in detail how the grey wolf optimization method should be adapted to perform color quantization, so that it generates a quantized palette that allows the quantized image to be represented. In this case, each individual in the group represents a quantized palette, which is improved with the information provided by the group. The detailed description of the algorithm is complemented by an extensive testing section that compares the results of the proposed method to those of 16 others techniques. The results, based on the comparison of MSE, MAE, PSNR, SSIM, and runtime, show that grey wolf optimization can generate good quality images, better than most of the compared methods.
Technical Library | 1999-08-27 09:24:56.0
Dispensing conductive adhesives in an automated factory environment creates some special challenges. A robust production process starts with understanding the adhesives in their fluid state and which important parameters must be controlled. Developing this understanding requires experience with a large number of materials and valves over time. Common uses of conductive adhesives in surface mount applications, die attach applications, and gasketing are addressed. As vendors of dispensing equipment, the authors see a constant stream of such applications. Dispensing requirements, techniques, and equipment resulting from this experience are discussed. Guidelines for optimizing quality and speed are given.
Technical Library | 2016-04-28 14:43:23.0
Underfilling is a long-standing process issued from the micro-electronics that can enhance the robustness and the reliability of first or second-level interconnects for a variety of electronic applications. Its usage is currently spreading across the industry fueled by the decreasing reliability margins induced by the miniaturization and interconnect pitch reduction. (...) This paper will address the control of surface mount under filled assemblies, focusing on applicable inspection techniques and possible options to overcome their limitations.
Technical Library | 2012-04-05 22:53:10.0
In this paper we show how hybrid control and modeling tech-niques can be put to work for solving a problem of industrial relevance in Surface Mount Technology (SMT) manufacturing. In particular, by closing the loop over the stencil printing process, we ob
Technical Library | 2008-11-06 02:17:59.0
For many years Acoustic Micro Imaging (AMI) techniques have been utilized to evaluate the quality of the underfill used to support the solder bump interconnections of Flip Chip type devices. AMI has been established as one of the few techniques that can provide reliability and quality control data, but little has been done to automate the evaluation process for Flip Chip underfill until now.
Technical Library | 2014-07-24 16:26:34.0
Wire bonding a die to a package has traditionally been performed using either aluminum or gold wire. Gold wire provides the ability to use a ball and stitch process. This technique provides more control over loop height and bond placement. The drawback has been the increasing cost of the gold wire. Lower cost Al wire has been used for wedge-wedge bonds but these are not as versatile for complex package assembly. The use of copper wire for ball-stitch bonding has been proposed and recently implemented in high volume to solve the cost issues with gold. As one would expect, bonding with copper is not as forgiving as with gold mainly due to oxide growth and hardness differences. This paper will examine the common failure mechanisms that one might experience when implementing this new technology.
Technical Library | 2018-03-21 22:44:30.0
Solder paste printing is the first step in the surface mount manufacturing process for PCBA assembly. When the solder paste printing process is uncontrolled, defects can be produced, which may not become apparent until the PCBA is downstream. (...)This paper will discuss how Lean Six Sigma techniques were used to optimize the solder paste printing process. It will highlight how a cross-functional team used the structured Define, Measure, Analyze, Improve and Control (DMAIC) methodology to identify and control the critical inputs. The advantage of the Lean Six Sigma methodology is that it guides the team through the rigorous structured process so that all possible inputs are considered and the critical ones can be identified.
Technical Library | 2024-05-31 19:29:15.0
A tight tolerance machine isn't necessarily a specific machine type. Rather, it's any machine capable of producing parts with precision tolerances. This means minimal variation in the final dimensions of the part. These cutting-edge tools are meticulously engineered to achieve exceptionally precise measurements within minuscule margins. This is accomplished with CNC, or computer numerical control, a manufacturing method that automates the movement of a machine and optimizes for precision. With technology and advanced techniques, these machines ensure that every component meets exact specifications, guaranteeing unparalleled accuracy in manufacturing processes.
Technical Library | 2018-02-22 10:56:36.0
As companies start to implement lead free soldering processes, hand soldering and associated techniques have been identified as key functions in the manufacturing process requiring additional research and development. Hand soldering tends to occur at the end of the process line where the circuit board has a high intrinsic value and so correct process control will have a significant affect on manufacturing costs and productivity.This paper discusses the fundamental aspects of the hand soldering process and discusses process adaptation requirements for successful lead free implementation.
