Electronics Manufacturing Technical Articles

Improve SMT Assembly Yields Using Root Cause Analysis in Stencil Design

Jul 18, 2018 | Greg Smith

Reduction of first pass defects in the SMT assembly process minimizes cost, assembly time and improves reliability. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining a successful and profitable assembly process. It is commonly accepted that the solder paste printing process causes the highest percentage of yield challenges in the SMT assembly process. As form factor continues to get smaller, the challenge to obtain 100% yield becomes more difficult.

This paper will identify defects affecting SMT yields in the printing process and discuss their Root Cause. Outer layer copper weight and surface treatment will also be addressed as to their effect on printability. Experiments using leadless and emerging components will be studied and root cause analysis will be presented...

Publisher: FCT ASSEMBLY, INC.

Improving Thermal Cycle and Mechanical Drop Impact Resistance of a Lead-free Tin-Silver-Bismuth-Indium Solder Alloy with Minor Doping of Copper Additive

Jul 11, 2018 | Takehiro Wada, Seiji Tsuchiya, Shantanu Joshi, Roberto Garcia, Kimiaki Mori, Takeshi Shirai

For a demanding automotive electronics assembly, a highly thermal fatigue resistant solder alloy is required, which makes the lead-free Sn-Ag-Cu type solder alloy unusable. Sn-Ag-Bi-In solder alloy is considered as a high reliability solder alloy due to significant improvement in thermal fatigue resistance as compared to a standard Sn-Ag-Cu alloy. The alloy has not only good thermal fatigue properties but it also has superior ductility and tensile strength by appropriate addition of In; however, initial results indicated a sub-par performance in joint reliability when it is soldered on a printed circuit board (PCB) with Electroless Nickel Immersion Gold (ENIG) surface finish. Numerous experiments were performed to find out appropriate alloying element which would help improve the performance on ENIG PCBs. Sn-Ag-Bi-In solder alloys with and without Cu additions were prepared and then tests were carried out to see the performance in a thermal fatigue test and a drop resistance test.to investigate the impact of Cu addition towards the improvement of joint reliability on ENIG finish PCB. Also, the mechanism of such improvement is documented....

Publisher: Koki Company LTD

Inkjet-Printed and Paper-Based Electrochemical Sensors

Jul 03, 2018 | Ryan P. Tortorich, Hamed Shamkhalichenar, Jin-Woo Choi

It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it is possible to produce devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Existing research has demonstrated that inkjet-printed and paper-based electrochemical sensors are suitable for this application due to advantages provided by the carefully selected materials and fabrication method. Inkjet printing provides a low cost fabrication method with incredible control over the material deposition process, while paper-based substrates enable pump-free microfluidic devices due to their natural wicking ability. Furthermore, electrochemical sensing is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment. By merging each of these favorable techniques and materials and continuing to innovate, the production of low-cost point-of-care sensors is certainly within reach...

Publisher: Louisiana State University

Flexible Hybrid Circuit Fully Inkjet-Printed: Surface Mount Devices Assembled By Silver Nanoparticles-Based Inkjet Ink

Jun 27, 2018 | J. Arrese, G. Vescio, E. Xuriguera, B. Medina-Rodriguez, A. Cornet, and A. Cirera

Nowadays, inkjet-printed devices such as transistors are still unstable in air and have poor performances. Moreover, the present electronics applications require a high degree of reliability and quality of their properties. In order to accomplish these application requirements, hybrid electronics is fulfilled by combining the advantages of the printing technologies with the surface-mount technology.

In this work, silver nanoparticle-based inkjet ink (AgNP ink) is used as a novel approach to connect surface-mount devices (SMDs) onto inkjet-printed pads, conducted by inkjet printing technology...

Publisher: Universitat de Barcelona

Design for Testability (DFT) to Overcome Functional Board Test Complexities in Manufacturing Test

Jun 20, 2018 | Louis Y. Ungar

Manufacturers test to ensure that the product is built correctly. Shorts, opens, wrong or incorrectly inserted components, even catastrophically faulty components need to be flagged, found and repaired. When all such faults are removed, however, functional faults may still exist at normal operating speed, or even at lower speeds. Functional board test (FBT) is still required, a process that still relies on test engineers’ understanding of circuit functionality and manually developed test procedures. While functional automatic test equipment (ATE) has been reduced considerably in price, FBT test costs have not been arrested. In fact, FBT is a huge undertaking that can take several weeks or months of test engineering development, unacceptably stretching time to market. The alternative, of selling products that have not undergone comprehensive FBT is equally, if not more, intolerable....

Publisher: A.T.E. Solutions, Inc.

1 Liter of Gap Filler in Only 13 Seconds - New Dispensing Solution for the Thermal Management for HV Batteries

Jun 18, 2018 | Scheugenpflug

Thermal influences can significantly compromise the service life, capacity and especially the operational safety of HV batteries. In order to prevent damage due to excessive temperatures, large quantities of heat-conducting potting media are used here. Scheugenpflug has developed a new system solution for fast and reliable application of these materials....

Publisher: Scheugenpflug Inc.

Unlocking The Mystery of Aperture Architecture for Fine Line Printing

Jun 13, 2018 | Clive Ashmore

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....

Publisher: ASM Assembly Systems GmbH & Co. KG

Potting in a Vacuum or Atmosphere?

Jun 04, 2018 | Scheugenpflug

Potting in a vacuum or atmospheric conditions? This question about the correct procedure concerns many users, among others i.e. electronics manufacturers, who pot more and more complex parts and components for a huge variety of products. Against the actual requirements of product and process, a decision on the procedure is often made under the assumption: „Potting under atmosphere = affordable and easy" and „Potting under vacuum = expensive and difficult". But that's a thing of the past. The way to the correct method, however, requires the clarification of a number of factors....

Publisher: Scheugenpflug Inc.

Green Supply Chain Management, Economic Growth and Environment: A GMM Based Evidence

May 30, 2018 | Syed Abdul Rehman Khan, Yu Zhang, Muhammad Anees, Heris Golpîra, Arij Lahmar, Dong Qianli

The aim of this research is to examine the relationship between green logistics operations and energy demand, economic growth and environmental sustainability need to make factors for relationship clearer in a panel data of 43 different countries around the globe. The study employed panel Generalized Method of Moments (GMM) estimates for robust inferences. The results have revealed that logistics operations consume energy and fossil fuel, while the amount of fossil fuel and non-green energy sources create significant harmful effect on the environmental sustainability and also have negative effect on economic growth. In addition, poor transport-related infrastructure and logistics service are a major contributor of CO2 and total greenhouse gas emissions. However, carbon emission damages fauna and flora, and reduces economic growth. The findings suggest that renewable energy sources and green practices can mitigate harmful effect of logistics operations on environmental sustainability and spur economic activities with greatly export opportunities in a region....

Publisher: Changan University

Wettable-Flanks: Enabler for the Use of Bottom-Termination Components in Mass Production of High-Reliability Electronic Control Units

May 23, 2018 | Udo Welzel, Marco Braun, Stefan Scheller, Sven Issing, Harald Feufel

Driven by miniaturization, cost reduction and tighter requirements for electrical and thermal performance, the use of lead-frame based bottom-termination components (LF-BTC) as small-outline no-leads (SON), quad-flat no leads (QFN) packages etc., is increasing. However, a major distractor for the use of such packages in high-reliability applications has been the lack of a visible solder (toe) fillet on the edge surface of the pins: because the post-package assembly singulation process typically leaves bare copper leadframe at the singulation edge, which is not protected against oxidation and thus does not easily solder-wet, a solder fillet (toe fillet) does not generally develop....

Publisher: Robert Bosch LLC Automotive Electronics Division