Technical Library | 2007-12-27 11:41:37.0
The latest screen printing platforms unlock more of the potential from dual-lane processing. Simultaneous demands to enhance flexibility while increasing utilisation and overall throughput apply to manufacturers operating at virtually any point in the mix-volume continuum: capacity must work hard to deliver the required return. As these lean manufacturing principles hold sway from the US and Europe to the Far East, no modern assembler has a second to spare.
Technical Library | 2010-05-12 16:21:05.0
Numerous studies have shown that greater than 60% of end of line defects in SMT assembly can be traced to solder paste and the printing process. Reflowing adds another 15% or so. In light of this fact, it is surprising that no simplified procedure for solder paste evaluation has been documented. This paper is about such a procedure.
Technical Library | 2012-12-27 14:35:29.0
Printed Electronics is generally defined as the patterning of electronic materials, in solution form, onto flexible substrates, omitting any use of the photolithography, etching, and plating steps commonly found within the Printed Circuit Board (PCB) industry. The origins of printed electronics go back to the 1960s, and close variants of several original applications and market segments remain active today. Through the 1980s and 1990s Printed Electronic applications based on Membrane Touch Switch and Electroluminescent lighting technologies became common, and the screen printed electronic materials used then have formed the building blocks for many of the current and emerging technologies and applications... First published in the 2012 IPC APEX EXPO technical conference proceedings.
Technical Library | 2018-03-15 07:23:35.0
The SMT assembly process is continuously challenged by the factors which enhance circuit board performance and limit productivity. The pick and place and reflow systems reflect these driven issues by adding more and more controls to their systems, but the fact is one of the age old processes continues to operate within the same rules since the dawn of the SMT assembly world: The SMT screen printing. (...)This paper showcases a new stencil process that was discovered by reverting to the basics:understanding the reason for each stencil material process, focusing on detailed finishes and a disciplined aperture design process, maintaining original designs, and making the correctly designed apertures to control the paste deposition. The test results drove us to focus the efforts on the aperture walls In this paper we will demonstrate with lab tests SMT process results howthe improved paste release results in improved SMT print process performance and its positive impact on SPI yields and EOL performance.
Technical Library | 2018-06-13 11:42:00.0
The art of screen printing solder paste for the surface mount community has been discussed and presented for several decades. However, the impending introduction of passive Metric 0201 devices has reopened the need to re-evaluate the printing process and the influence of stencil architecture. The impact of introducing apertures with architectural dimensions’ sub 150um whilst accommodating the requirements of the standard suite of surface mount connectors, passives and integrated circuits will require a greater knowledge of the solder paste printing process.The dilemma of including the next generation of surface mount devices into this new heterogeneous environment will create area ratio challenges that fall below todays 0.5 threshold. Within this paper the issues of printing challenging area ratio and their associated aspect ratio will be investigated. The findings will be considered against the next generation of surface mount devices.
Technical Library | 2014-12-24 19:22:52.0
For centuries, the squeegee blade has been used throughout many applications for depositing viscous materials through screens and stencils to transfer images on to substrates, from cloth material to electronic circuit boards. One area of blade printing mechanics that have been reviewed many times is the angle of attack of the blade. Typically it has been tested from 45 degrees to 60 degrees to optimize the printing quality and efficiency. However, this typically ends up as a compromise, from fill characteristics (45 degrees) to print definition (60 degrees). This paper will present the revolutionary performance of the profiled squeegee blade, which has recently been developed to create a virtual multi angle of attack for unsurpassed process control for all types of stencil printing processes.
Technical Library | 2017-03-09 17:37:05.0
This article focuses on the fabrication and characterization of stretchable interconnects for wearable electronics applications. Interconnects were screen-printed with a stretchable silver-polymer composite ink on 50-μm thick thermoplastic polyurethane. The initial sheet resistances of the manufactured interconnects were an average of 36.2 mΩ/◽, and half the manufactured samples withstood single strains of up to 74%. The strain proportionality of resistance is discussed, and a regression model is introduced. Cycling strain increased resistance. However, the resistances here were almost fully reversible, and this recovery was time-dependent. Normalized resistances to 10%, 15%, and 20% cyclic strains stabilized at 1.3, 1.4, and 1.7. We also tested the validity of our model for radio-frequency applications through characterization of a stretchable radio-frequency identification tag.
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 | 2007-12-13 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 | 2015-07-31 16:28:16.0
Technology is in constant change and circuit assembly is no different. It is becoming more and more advanced as needs change and demands for more capabilities increase. In order to meet these demands, equipment manufacturers are integrating the latest innovations and tools to serve the industry. The need to better protect printed circuit assemblies from harsh environments using automated selective conformal coating is becoming a must. 5 axis fluid dispensing allows conformal coating to be applied to printed circuit assemblies like never before.
