Technical Library | 2023-06-12 19:07:04.0
In this article we will examine if there is a measurable difference in the printing performance when using stencils which have a higher tension than is commonly accepted in the industry. Alpha's new tensoRED™ High Tension Frame System will be introduced during this wider examination. We will examine their effect in terms of controlling variation in critical deposit volumes and what, if any effect on positional accuracy can be seen.
Technical Library | 2007-12-13 17:03:02.0
Printer-hosted processes for solder ball placement are now widely used for package technologies ranging from BGAs using ball diameters above 750μm to the latest WL-CSPs demanding 250μm diameter. This broadening spectrum of applications brings more choices in terms of stencil design rules and production methodologies.
Technical Library | 2011-01-06 18:03:18.0
The oven recipe, which consists of the reflow oven zone temperature settings and the speed of the conveyor, will determine a specific time‐temperature profile for a given PCB assembly. In order to achieve a good quality PCB assembly, the time‐temperature
Technical Library | 2020-03-04 23:53:17.0
Critical to maintaining quality control in high-throughput screening is the need for constant monitoring of liquid-dispensing fidelity. Traditional methods involve operator intervention with gravimetric analysis to monitor the gross accuracy of full plate dispenses, visual verification of contents, or dedicated weigh stations on screening platforms that introduce potential bottlenecks and increase the plate-processing cycle time. We present a unique solution using open-source hardware, software, and 3D printing to automate dispenser accuracy determination by providing real-time dispense weight measurements via a network-connected precision balance. This system uses an Arduino microcontroller to connect a precision balance to a local network. By integrating the precision balance as an Internet of Things (IoT) device, it gains the ability to provide real-time gravimetric summaries of dispensing, generate timely alerts when problems are detected, and capture historical dispensing data for future analysis. All collected data can then be accessed via a web interface for reviewing alerts and dispensing information in real time or remotely for timely intervention of dispense errors. The development of this system also leveraged 3D printing to rapidly prototype sensor brackets, mounting solutions, and component enclosures.
Technical Library | 2007-11-29 17:20:31.0
Programs have been developed to predict the expected yield of flip chip assemblies, based on substrate design and the statistics of actual manufactured boards, as well as placement machine accuracy, variations in bump sizes, and possible substrate warpage. These predictions and the trends they reveal can be used to direct changes in design so that defect levels will fall below the acceptable limits. Shapes of joints are calculated analytically, or when this is not possible, numerically by means of a public domain program called Surface Evolver. The method is illustrated with an example involving the substrate for a flip chip BGA.
Technical Library | 2015-06-22 18:31:52.0
Applying conformal coatings to electronics has come a long way since the days of manually coating circuit boards. The extreme accuracy and highly repetitive process of automated conformal coatings is moving the electronics industry towards a more defect-free era for conformal coating. It enables new forms of electronics to become better protected, making it possible for electronics to withstand harsher environments than ever before. The following article is meant to aid in clarifying the advantages of specialty coating systems over manual applications for selective conformal coating.
Technical Library | 2021-06-15 15:11:43.0
Today's automated dispensing for electronics manufacturing is a complex and precise process in order to meet the challenges posed by ever more demanding assembly and component technology requirements. Dedicated dispenser technology is key to success in meeting challenging applications in a production environment with precision and repeatability. The major components that comprise a dispenser will be described, with a view toward understanding the importance of each; the result will illustrate how these sub-systems combine to create high-volume dispensing platforms. Real world examples with data substantiating the speed and accuracy obtained for some of the most common advanced dispensing applications in the market will be demonstrated such as high speed surface mount adhesive, wafer level Underfill and shield edge interconnects.
Technical Library | 2021-11-22 20:32:10.0
The aim of this work is to define a procedure to develop diagnostic systems for Printed Circuit Boards, based on Automated Optical Inspection with low cost and easy adaptability to different features. A complete system to detect mounting defects in the circuits is presented in this paper. A low cost image acquisition system with high accuracy has been designed to fit this application. Afterward, the resulting images are processed using the Wavelet Transform and Neural Networks, for low computational cost and acceptable precision. The wavelet space represents a compact support for efficient feature extraction with the localization property. The proposed solution is demonstrated on several defects in different kind of circuits.
Technical Library | 2014-04-03 18:01:13.0
A system level modeling methodology is presented and validated on a simple case. It allows precise simulations of electrostatic discharge (ESD) stress propagation on a printed circuit board (PCB). The proposed model includes the integrated circuit (IC) ESD protection network, IC package, PCB lines, passives components, and externals elements. The impact of an external component on the ESD propagation paths into an IC is demonstrated. Resulting current and voltage waveforms are analyzed to highlight the interactions between all the elements of an operating PCB. A precise measurement technique was designed and used to compare with the simulation results. The model proposed in this paper is able to predict, with good accuracy, the propagation of currents and voltages into the whole system during ESD stress. It might be used to understand why failures occur and how to fix them with the most suitable solution.
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.
