Electronics Manufacturing Technical Articles

Solder Paste Dispensing For Aerospace and Defense

Aug 16, 2023 | GPD Global, Inc.

A global aerospace and defense leader requested a capability test of small volume solder paste dispensing on FR4 circuit boards....

Publisher: GPD Global

LED Encapsulation for Consumer Products

Aug 16, 2023 | GPD Global, Inc.

In one of our Consumer Electronics projects, a smart lighting company wished to dispense silicone-based LED encapsulation material for two different product sizes. The larger product had a 9mm circular dam which required silicone dispensing flush with the top of the dam. The smaller product had a 1mm LED die that required only the top to be encapsulated. The material consisted of two parts which were mixed by weight in a 1:1 ratio. A phosphor powder was added totaling 10% of the overall weight. The phosphor required agitation to remain suspended....

Publisher: GPD Global

Solder Mask Dispensing For Electronics and Aerostructures

Aug 16, 2023 | GPD Global, Inc.

One of our customers involved with Electronics and Aerostructures requested a test to dispense Techspray Wondermask 2204 solder mask. The dispensing locations include large and small screw holes, single through-hole vias, and connector locations consisting of multiple through-hole vias. The process needed to run quickly and reliably....

Publisher: GPD Global

Dam and Fill Dispensing for Medical

Aug 16, 2023 | GPD Global, Inc.

One of our customers in the medical industry requested dam and fill application testing on a Kapton substrate. The material needed to be non-conductive for dispensing around electrical components, acting as structural support. Ultimately the product will be folded, therefore the footprint had to be small....

Publisher: GPD Global

HALT/HASS and Thermal Cycling to Assess COTS Boards, GoPro Camera and Advanced PBGA/CCGA Virtex-5Electronic Packages

Aug 14, 2023 | Rajeshuni Ramesham Ph.D.

Outline Introduction Objectives Hardware to be assessed COTS Xilinx and Microsemi ProASIC Boards Advanced CCGA/Virtex-5Daisy Chain Package (Kyocera) Assembled Advanced SMT packages (PBGA) COTS GoPro Camera Experimental Details Test Results/Discussion Summary Acknowledgements...

Publisher: NASA Office Of Safety And Mission Assurance

Benefits and Costs of Overstress Testing (HALT)

Aug 14, 2023 | Nahum Meadowsong & Edmond L. Kyser

The partnership of Design and Manufacturing is central to the process of bringing a product to market. The impact of problems in either of these stages can increase exponentially if they go unnoticed until after the product reaches the customer. Overstress Test (tests using stresses beyond the design limit of the product) is successful at uncovering such faults in both product design and the manufacturing process and insures the overall robustness of the product. The benefits of Overstress Test include ......

Publisher: Cisco Systems, Inc.

SMT Placement Machine Nozzle Maintenance and Operation Instructions from KINGSUN

Aug 14, 2023 | KSUNSMT

In the operation of SMT mounter, the process and integrity of the nozzle of the mounter will have a significant impact on the performance of the machine. As one of the important components of the SMT machine, it is necessary for us to carry out daily maintenance and upkeep of the SMT nozzle. To ensure that the suction nozzle of the SMT machine is intact before operation, how should we do a good job of maintaining the suction nozzle of the SMT machine during normal use? KINGSUN technical team analysis operation has the following main points: 1.Wipe the surface of the SMT nozzle with a dust-free cloth. 2.The small aperture nozzle can be passed through with a thin steel wire and then blown with an air gun. 3.The surface of the nozzle should not be soaked with corrosive solution such as alcohol, as this may cause the surface to fall off. 4.HOLDER should use a cotton swab to wipe the cavity and not damage the filter screen. 5.Regular addition of special grease to HOLDER claws. 6.According to production, it is best to regularly maintain and do other maintenance regularly. (* Suitable for Yamaha SMT machine nozzles , JUKI SMT machine nozzles, Samsung SMT machine nozzles, Panasonic SMT machine nozzles, Fuji SMT machine nozzles, Siemens SMT machine nozzles etc.) Regarding the SMT machine nozzle daily maintenance operation instructions, KINGSUN share with you here , hoping to be helpful to you. More information about Products please Contact US at jenny@ksunsmt.com or visit www.ksunsmt.com , thanks....

Publisher: DONGGUAN KINGSUN AUTOMATION TECHNOLOGY CO.,LTD

Improved QFN Reliability by Flank Tin Plating Process after Singulation

Aug 04, 2023 | John Ganjei

The process of singulating IC packages such as Quad Flat Pack No-Lead (QFNs) by either a sawing or punching operation results in exposed copper on the sidewalls. This exposed copper surface can oxidize leading to poor or no solder wetting up the sidewall during the assembly operation. The consequence of this oxidized copper surface is either incomplete or no solder fillet formation during the PCB mounting operation resulting in solder joint reliability concerns. Currently, JEDEC and IPC assembly standards do not specify a toe fillet for assembly. However, several component manufacturers have requested a toe fillet solderability process which would improve current QFN reliability by ensuring toe fillet solder coverage. A process whereby tin is plated on the copper sidewall of the QFN after singulation has been developed to improve toe fillet solderability. Several assembly studies have been conducted which demonstrate improved QFN reliability due to the use of this toe fillet solderability process. The plating process, toe fillet inspection and improved QFN reliability after assembly due to the use of this toe fillet solderability is described....

Publisher: Omg Electrochemicals / Macdermid Alpha

Side Wettable Flanks for Leadless Automotive Packaging

Aug 04, 2023 | Marc A. Mangrum

The MicroLeadFrame® (MLF®)/Quad Flat No-Lead (QFN) packaging solution is extremely popular in the semiconductor industry. It is used in applications ranging from consumer electronics and communications to those requiring high reliability performance, such as the automotive industry. The wide acceptance of this packaging design is primarily due to its flexible form factors, size, scalability and thermal dissipation capabilities. The adaptation and acceptance of MLF/QFN packages in automotive high reliability applications has led to the development of materials and processes that have extended its capabilities to meet the performance and quality requirements. One of process developments that is enabling the success of the MLF/QFN within the automotive industry has been the innovation of side wettable flanks that provide the capability to inspect the package lead to printed circuit board (PCB) interfaces for reliable solder joints. Traditionally, through-board X-ray was the accepted method for detecting reliable solder joints for leadless packages. However, as PBC layer counts and routing complexities have increased, this method to detect well-formed solder fillets has proven ineffective and incapable of meeting the inspection requirements. To support increased reliability and more accurate inspection of the leadless package solder joints, processes to form side-wettable flanks have been developed. These processes enable the formation of solder fillets that are detectable using state-of-the-art automated optical inspection (AOI) equipment, providing increased throughput for the surface mount technology (SMT) processes and improved quality as well....

Publisher: Amkor Technology, Inc.

Factors That Influence Side-Wetting Performance on IC Terminals

Aug 04, 2023 | Donald C. Abbott, Bernhard Lange, Douglas W. Romm, and John Tellkamp

A designed experiment evaluated the influence of several variables on appearance and strength of Pb-free solder joints. Components, with leads finished with nickel-palladium-gold (NiPdAu), were used from Texas Instruments (TI) and two other integrated circuit suppliers. Pb-free solder paste used was tin-silver-copper (SnAgCu) alloy. Variables were printed wiring board (PWB) pad size/stencil aperture (the pad finish was consistent; electrolysis Ni/immersion Au), reflow atmosphere, reflow temperature, Pd thickness in the NiPdAu finish, and thermal aging. Height of solder wetting to component lead sides was measured for both ceramic plate and PWB soldering. A third response was solder joint strength; a "lead pull" test determined the maximum force needed to pull the component lead from the PWB. This paper presents a statistical analysis of the designed experiment. Reflow atmosphere and pad size/stencil aperture have the greatest contribution to the height of lead side wetting. Reflow temperature, palladium thickness, and preconditioning had very little impact on side-wetting height. For lead pull, variance in the data was relatively small and the factors tested had little impact....

Publisher: Texas Instruments

A Process For Improved QFN Reliability

Aug 04, 2023 | Lenora Toscano, John Ganjei, Ph.D, Richard Retallick, and Gu Hong, Ph.D

The process of singulating IC packages such as Quad Flat Pack No-Lead (QFNs) by either a sawing or punching operation results in exposed copper on the sidewalls. This exposed copper surface can oxidize leading to poor or no solder wetting up the sidewall during the assembly operation. The consequence of this oxidized copper surface is either incomplete or no solder fillet formation during the PCB mounting operation resulting in solder joint reliability concerns. Currently, JEDEC and IPC assembly standards do not specify a toe fillet for assembly. However, several component manufacturers have requested a toe fillet solderability process which would improve current QFN reliability by ensuring toe fillet solder coverage A process whereby tin is plated on the copper sidewall of the QFN after singulation has been developed to improve toe fillet solderability. Several assembly studies have been conducted which demonstrate improved QFN reliability due to the use of this toe fillet solderability process. The plating process, toe fillet inspection and improved QFN reliability after assembly due to the use of this toe fillet solderability is described....

Publisher: Omg Electrochemicals / Macdermid Alpha

DPBO – A New Control Chart For Electronics Assembly

Aug 02, 2023 | Daryl L. Santos, Ph.D.

As six sigma (6) and better processes are demanded for higher yields and as organizations move from measuring defects in terms of parts-per-million (ppm) towards parts-per-billion (ppb), the resolution of extant control charts is becoming insufficient to monitor process quality. This work describes the development of a new statistical process control (SPC) chart that is used to monitor processes in terms of defects-per-billion-opportunities (dpbo). A logical extension of the defects-per-million-opportunities (dpmo) control chart, calculations used to derive the dpbo control limits will be presented and examples of in-control and out-of-control processes will be offered....

Publisher: Binghamton University

Life and death decisions of autonomous vehicles

Jul 31, 2023 | Yochanan E. Bigman & Kurt Gray

How should self-driving cars make decisions when human lives hang in the balance? The Moral Machine experiment1 (MME) suggests that people want autonomous vehicles (AVs) to treat different human lives unequally, preferentially killing some people (for example, men, the old and the poor) over others (for example, women, the young and the rich). Our results challenge this idea, revealing that this apparent preference for inequality is driven by the specific ‘trolley-type’ paradigm used by the MME. Multiple studies with a revised paradigm reveal that people overwhelmingly want autonomous vehicles to treat different human lives equally in life and death situations, ignoring gender, age and status—a preference consistent with a general desire for equality

Publisher: University of North Carolina at Chapel Hill

Governing Autonomous Vehicles: Emerging Responses For Safety, Liability, Privacy, Cybersecurity, And Industry Risks

Jul 31, 2023 | Araz Taeihagh and Hazel Si Min Lim

The benefits of autonomous vehicles (AVs) are widely acknowledged, but there are concerns about the extent of these benefits and AV risks and unintended consequences. In this article, we first examine AVs and different categories of the technological risks associated with them. We then explore strategies that can be adopted to address these risks, and explore emerging responses by governments for addressing AV risks. Our analyses reveal that, thus far, governments have in most instances avoided stringent measures in order to promote AV developments and the majority of responses are non-binding and focus on creating councils or working groups to better explore AV implications. The US has been active in introducing legislations to address issues related to privacy and cybersecurity. The UK and Germany, in particular, have enacted laws to address liability issues; other countries mostly acknowledge these issues, but have yet to implement specific strategies. To address privacy and cybersecurity risks strategies ranging from introduction or amendment of non-AV specific legislation to creating working groups have been adopted. Much less attention has been paid to issues such as environmental and employment risks, although a few governments have begun programmes to retrain workers who might be negatively affected....

Publisher: National University of Singapore

A Safety Standard Approach for Fully Autonomous Vehicles

Jul 31, 2023 | Philip Koopman, Uma Ferrell, Frank Fratrik, Michael Wagner

Assuring the safety of self-driving cars and other fully autonomous vehicles presents significant challenges to traditional software safety standards both in terms of content and approach. We propose a safety standard approach for fully autonomous vehicles based on setting scope requirements for an overarching safety case. A viable approach requires feedback paths to ensure that both the safety case and the standard itself co-evolve with the technology and accumulated experience. An external assessment process must be part of this approach to ensure lessons learned are captured, as well as to ensure transparency. This approach forms the underlying basis for the UL 4600 initial draft standard.

Publisher: Edge Case Research

High-precision dispensing technology: Potting technology for medical wearables

Jul 27, 2023 | Scheugenpflug

Diabetes affects many millions of people worldwide. New technology for real-time glucose measurement replaces the usual unpleasant pricking of a finger: a sensor located in the subcutaneous tissue of the diabetes patient measures the glucose values and transmits them to a receiver. Production of such medical wearables calls for high-precision dispensing systems for applying very small amounts of UV adhesives to medical PCBs and for integrated system concepts to achieve this. A perfect task for Scheugenpflug....

Publisher: Scheugenpflug Inc.

A Study of the Aperture Filling Process in Solder Paste Stencil Printing

Jul 25, 2023 | Jianbiao Pan, G. Tonkay

Stencil printing has been the dominant method of solder deposition in surface mount assembly. With the development of advanced packaging technologies such as ball grid array (BGA) and flip chip on board (FCOB), stencil printing will continue to play an important role. However, the stencil printing process is not completely understood because 52–71 percent of fine and ultra-fine pitch surface mount assembly defects are printing process related (Clouthier, 1999). This paper proposes an analytical model of the solder paste deposition process during stencil printing. The model derives the relationship between the transfer ratio and the area ratio. The area ratio is recommended as a main indicator for determining the maximum stencil thickness. This model explains two experimental phenomena. One is that increasing stencil thickness does not necessarily lead to thicker deposits. The other is that perpendicular apertures print thicker than parallel apertures....

Publisher: Lehigh University

Solder Paste Deposition Project Report

Jul 25, 2023 | Cherie Chen

INTRODUCTION: ...

Publisher: iNEMI (International Electronics Manufacturing Initiative)

Step Stencil design when 01005 and 0.3mm pitch uBGA's coexist with RF Shields

Jul 25, 2023 | William E. Coleman Ph.D.

Some of the new handheld communication devices offer real challenges to the paste printing process. Normally, there are very small devices like 01005 chip components as well as 0.3 mm pitch uBGA along with other devices that require higher deposits of solder paste. Surface mount connectors or RF shields with coplanarity issues fall into this category. Aperture sizes for the small devices require a stencil thickness in the 50 to 75 um (2-3 mils) range for effective paste transfer whereas the RF shield and SMT connector would like at least 150 um (6 mils) paste height. Spacing is too small to use normal step stencils. This paper will explore a different type of step stencil for this application; a "Two-Print Stencil Process" step stencil. Here is a brief description of a "Two-Print Stencil Process". A 50 to 75 um (2-3 mils) stencil is used to print solder paste for the 01005, 0.3 mm pitch uBGA and other fine pitch components. While this paste is still wet a second in-line stencil printer is used to print all other components using a second thicker stencil. This second stencil has relief pockets on the contact side of the stencil any paste was printed with the first stencil. Design guidelines for minimum keep-out distances between the relief step, the fine pitch apertures, and the RF Shields apertures as well relief pocket height clearance of the paste printed by the first print stencil will be provided....

Publisher: Photo Stencil LLC

Stencil Options for Printing Solder Paste for .3 Mm CSP's and 01005 Chip Components

Jul 25, 2023 | William E. Coleman Ph.D. , Chris Anglin

Printing solder paste for very small components like .3mm pitch CSP's and 01005 Chip Components is a challenge for the printing process when other larger components like RF shields, SMT Connectors, and large chip or resistor components are also present on the PCB. The smaller components require a stencil thickness typically of 3 mils (75u) to keep the Area Ratio greater than .55 for good paste transfer efficiency. The larger components require either more solder paste height or volume, thus a stencil thickness in the range of 4 to 5 mils (100 to 125u). This paper will explore two stencil solutions to solve this dilemma. The first is a "Two Print Stencil" option where the small component apertures are printed with a thin stencil and the larger components with a thicker stencil with relief pockets for the first print. Successful prints with Keep-Outs as small as 15 mils (400u) will be demonstrated. The second solution is a stencil technology that will provide good paste transfer efficiency for Area Ratio's below .5. In this case a thicker stencil can be utilized to print all components. Paste transfer results for several different stencil types including Laser-Cut Fine Grain stainless steel, Laser-Cut stainless steel with and w/o PTFE Teflon coating, AMTX E-FAB with and w/o PTFE coating for Area Ratios ranging from .4 up to .69....

Publisher: Photo Stencil LLC

Stencil Print solutions for Advance Packaging Applications

Jul 25, 2023 | Phani Vallabhajosyula, PhD

This paper address two significant applications of stencils in advance packaging field: 1. Ultra-Thin stencils for miniature component (0201m) assembly; 2. Deep Cavity stencils for embedded (open cavity) packaging. As the world of electronics continues to evolve with focus on smaller, lighter, faster, and feature-enhanced high- performing electronic products, so are the requirement for complex stencils to assemble such components. These stencil thicknesses start from less than 25um with apertures as small as 60um (or less). Step stencils are used when varying stencil thicknesses are required to print into cavities or on elevated surfaces or to provide relief for certain features on a board. In the early days of SMT assembly, step stencils were used to reduce the stencil thickness for 25 mil pitch leaded device apertures. Thick metal stencils that have both relief-etch pockets and reservoir step pockets are very useful for paste reservoir printing. Electroform Step-Up Stencils for ceramic BGA's and RF Shields are a good solution to achieve additional solder paste height on the pads of these components as well as providing exceptional paste transfer for smaller components like uBGAs and 0201s. As the components are getting smaller, for example 0201m, or as the available real estate for component placement on a board is getting smaller – finer is the aperture size and the pitch on the stencils. Aggressive distances from step wall to aperture are also required. Ultra-thin stencils with thicknesses in the order of 15um-40um with steps of 15um are used to obtain desired print volumes. Stencils with thickness to this order can be potential tools even to print for RDLs in the package....

Publisher: Photo Stencil LLC

KE-2050/KE-2060 Causes and Countermeasures of Patch Failure

Jul 22, 2023 | KSUNSMT

Patch offset; Uneven patches throughout the substrate (each substrate is offset in a different way); Only part of the substrate is offset; Only certain components are offset; The patch Angle is offset; Component absorption error; Laser identification (component identification) error; Nozzle loading and unloading error; Mark (BOC mark, IC mark) identification error; Image recognition error (KE-2060 only); Analysis of the main reasons for throwing material. More information about KINGSUN please Contact US at jenny@ksunsmt.com or visit www.ksunsmt.com...

Publisher: DONGGUAN KINGSUN AUTOMATION TECHNOLOGY CO.,LTD

SMT, DIP, PCBA conformal coating equipment and turnkey solution

Jul 21, 2023 | I.C.T

I.C.T is a manufacturer from China that offers SMT, DIP, PCBA conformal coating equipment and turnkey solution....

Publisher: I.C.T ( Dongguan ICT Technology Co., Ltd. )

Applied Statistics and Experimental Design

Jul 16, 2023 | Fritz Scholz

Statistics originally served to describe matters of the state (status of state) by capturing numerically various aspects of full populations. Today this is called a census, from Latin censere (to count or estimate). Recall the historical census of Emperor Augustus. Nowadays the field of statistics focusses mainly on samples, i.e., part of the total. The goal is to make statements or conclusions about the whole population. This process is referred to as induction, from Latin inducere (to lead to). Its validity depends crucially on the process of sampling. Sample   example from Latin exemplum.

Publisher: University of Washington

Design of Experiment Methods in High Speed Signal Via Transition in Printed Circuit Board

Jul 16, 2023 | Amir A. Asif,

With increase in data transfer speeds between integrated circuits, memories and connectors, the interconnects in printed circuit boards require careful design and optimization. A critical part of an interconnect is via transition. To meet the design goals and maintain signal integrity, every part of the interconnect needs to be carefully designed. Designing via involves variation of several parameters and it is extremely important to understand their contribution to find the usable parameters yielding best possible performance. Out of these numerous combinations of parameters, Design of Experiments (DOE) can offer much needed understanding, suggest possible values and speed up the design process. In this manuscript, two DOE methods (Box-Behnken Design and Central Composite Design) are used to understand the behavior of a pair of vias operating in differential mode.

Publisher: Clemson University

The Compensation Problem and Solution Using Design of Experiments for Dense Multilayer Printed Circuit Boards

Jul 16, 2023 | Wm. Gray McQuarrie

Imagine being able to accurately predict the correct artwork compensations prior to taking on a large quick turn order regardless of the board design, materials, or process. Such predictive power is possible and can be achieved without a lot of cost and complexity. This paper shows how small sets of designed experiments can be used to create a cImagine being able to accurately predict the correct artwork compensations prior to taking on a large quick turn order regardless of the board design, materials, or process. Such predictive power is possible and can be achieved without a lot of cost and complexity. This paper shows how small sets of designed experiments can be used to create a compensation model. Before a discussion of the design of experiments (DOEs), we will examine key processes and material variables that affect movement as demonstrated on real board design layout in a real production process. Only the few most relevant variables need to be included in the experimental design. A solution is presented that uses small experiments that provide the required information for constructing a general compensation model.mpensation model. Before a discussion of the design of experiments (DOEs), we will examine key processes and material variables that affect movement as demonstrated on real board design layout in a real production process. Only the few most relevant variables need to be included in the experimental design. A solution is presented that uses small experiments that provide the required information for constructing a general compensation model....

Publisher: Isola Group

Verifying the efficiency of soldering fume extraction and measuring nanoparticle exposure during soldering with an iron with the testo DiSCmini

Jul 10, 2023 | Testo

That manual soldering produces harmful substances in the form of aerosols is a known problem in the electric and electronic industry. The lead-free electronics solders used today have done little to change that. The soldering fumes still contain particles which are formed by the solder and the flux agent. These particles have a high potential of causing permanent damage to the workers’ health. Due to their small diameter between 10 and 150 nm, they can penetrate all the way into the alveoli. But numerous studies also show that nanoparticles can reach all areas of the body through the bloodstream [1].

Publisher: Testo SE & Co. KGaA

CLEANING BEFORE CONFORMAL COATING

Jul 04, 2023 | Naveen Ravindran

CONTENT * Introduction * Failure Mechanisms * Coating Failures * Cleaning Before Conformal Coating * Analytics & Test Methods...

Publisher: ZESTRON Americas

Conformal Coating Defects

Jul 04, 2023 | Diamond MT

Conformal Coatings are polymeric materials used to protect circuitry, parts, and related components. They are most commonly used to protect printed circuit boards (PCBs) and electronic devices. However, conformal coatings can be applied to a wide variety of materials, including metal, plastic, silicone, ceramics, glass, and even paper. We use the term "substrate" to refer to an object or material that's been coated with a conformal coating....

Publisher: Diamond MT

The Effects of Silver Content and Solidification Profile on the Anand Constitutive Model for SAC Lead Free Solders

Jun 14, 2023 | Munshi M. Basit, Mohammad Motalab, Jordan C. Roberts, Jeffrey C. Suhling, Pradeep Lall

In the electronic packaging industry, it is important to be able to make accurate predictions of board level solder joint reliability during thermal cycling exposures. The Anand viscoelastic constitutive model is often used to represent the material behavior of the solder in finite element simulations. This model is defined using nine material parameters, and the reliability prediction results are often highly sensitive to the Anand parameters. In this work, an investigation on the Anand constitutive model and its application to SAC solders of various Ag contents (i.e. SACN05, with N = 1, 2, 3, 4) has been performed. For each alloy, both water quenched (WQ) and reflowed (RF) solidification profiles were utilized to establish two unique specimen microstructures, and the same reflow profile was used for all four of the SAC alloys so that the results could be compared and the effects of Ag content could be studied systematically....

Publisher: Auburn University

Using Stencil: Design to Reduce SMT Defects

Jun 12, 2023 | Paul Lotosky, Michael Murphy, Robert Pearson, Michael Tesch

Solder paste printing is understood to be the leading contributor of defects in the electronics assembly process. Because yield accounts for such a large percentage of the margin, the greatest opportunity to improve profitability in the assembly of most electronics can be gained by reducing or eliminating solder defects. This article examines process adjustments made through stencil design that correct a misalignment situation between the PCB and stencil, leading to a 43% reduction in assembly defects. Examples of each are found in Table 1....

Publisher: AVI Precision Engineering Pte Ltd

Optimizing Stencil Design For Lead-Free Smt Processing

Jun 12, 2023 | Ranjit S Pandher, Chrys Shea

As any new technology emerges, increasing levels of refinement are required to facilitate the mainstream implementation and continual improvement processes. In the case of lead-free processing, the initial hurdles of alloy and chemistry selection are cleared on the first level, providing a base process. The understanding gained from early work on the base process leads to the next level of refinement in optimizing the primary factors that influence yield. These factors may include thermal profiles, PWB surface finishes, component metallization, solder mask selection or stencil design....

Publisher: Cookson Electronics Assembly Materials

The Effect of Higher Stencil Tension on Printing Performance

Jun 12, 2023 | Tom Meeus, Jan Van Lieshout, Hans Korsse, Sathiya Naryana

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....

Publisher: Alpha Assembly Solutions

Stencil Printing Process Tools for Miniaturisation and High Yield Processing

Jun 12, 2023 | Clive Ashmore & Mark Whitmore

The SMT print process is now very mature and well understood. However as consumers continually push for new electronic products, with increased functionality and smaller form factor, the boundaries of the whole assembly process are continually being challenged. Miniaturisation raises a number of issues for the stencil printing process. How small can we print? What are the tightest pitches? Can we print small deposits next too large for high mix technology assemblies? How closely can we place components for high density products? ...And then on top of this, how can we satisfy some of the cost pressures through the whole supply chain and improve yield in the production process! Today we are operating close to the limits of the stencil printing process. The area ratio rule (the relationship between stencil aperture opening and aperture surface area) fundamentally dictates what can and cannot be achieved in a print process. For next generation components and assembly processes these established rules need to be broken! New stencil printing techniques are becoming available which address some of these challenges. Active squeegees have been shown to push area ratio limits to new boundaries, permitting printing for next generation 0.3CSP technology. Results also indicate there are potential yield benefits for today's leading edge components as well. Stencil coatings are also showing promise. In tests performed to date it is becoming apparent that certain coatings can provide higher yield processing by extending the number of prints that can be performed in-between stencil cleans during a print process. Preliminary test results relating to the stencil coating technology and how they impact miniaturisation and high yield processing will be presented....

Publisher: ASM Assembly Systems (DEK)

Stencil Design For Mixed Technology Through-Hole / Smt Placement And Reflow

Jun 12, 2023 | William E. Coleman, Denis Jean, Julie Bradbury

This paper will review stencil design requirements for printing solder paste around and in through-hole pads / openings. There is much interest in this procedure since full implementation allows the placement of both through-hole components as well as SMD's and the subsequent reflow of both simultaneously. This in turn eliminates the need to wave solder or hand solder through-hole components....

Publisher: Photo Stencil LLC

Recurrent Neural Network-Based Stencil Cleaning Cycle Predictive Modeling

Jun 12, 2023 | Haifeng Wang, Tian He, and Sang Won Yoon

This paper presents a real-time predictive approach to improve solder paste stencil printing cycle decision making process in surface mount assembly lines. Stencil cleaning is a critical process that influences the quality and efficiency of printing circuit board. Stencil cleaning operation depends on various process variables, such as printing speed, printing pressure, and aperture shape. The objective of this research is to help efficiently decide stencil printing cleaning cycle by applying data-driven predictive methods. To predict the printed circuit board quality level, a recurrent neural network (RNN) is applied to obtain the printing performance for the different cleaning aging. In the prediction model, not only the previous printing performance statuses are included, but also the printing settings are used to enhance the RNN learning. The model is tested using data collected from an actual solder paste stencil printing line. Based on the predicted printing performance level, the model can help automatically identify the possible cleaning cycle in practice. The results indicate that the proposed model architecture can predictively provide accurate solder paste printing process information to decision makers and increase the quality of the stencil printing process....

Publisher: Binghamton University

The Solder Paste Printing Process: Critical Parameters, Defect Scenarios, Specifications, And Cost Reduction

Jun 12, 2023 | Chien-Yi Huang, Yueh-Hsun Lin, Kuo-Ching Ying, Chen-Liang Ku

The purpose of this paper is to comprehensively explore the effects of critical parameters on solder deposition and to establish a systematic approach for determining guidelines for solder paste inspection (SPI) workstations. Design/methodology/approach – This study explored the effects of process parameters, stencil and printed circuit board designs on solder deposition and identified the major post-reflow defect scenarios. Through the investigation of correlation between the results of SPI analysis and post-reflow defective scenarios, SPI specifications are suggested for minimizing the total cost of poor quality. Findings – The higher the printing pressure the lower the solder deposition. There was a significant difference in solder deposition between the front squeegee and the rear squeegee. Insufficient distance between the stencil aperture and the initial printing location resulted in irregular solder paste and variations in solder deposition. A stencil with a higher area ratio resulted in greater solder deposition and less variation. Stencil apertures parallel to the direction of printing were superior to a 458 vector print. Further, the nominal solder thickness should take into account the thicknesses of the solder mask and the legend ink. There was an offset in the results of SPI measurements between the solder mask defined (SMD) pads and non-SMD pads. The specifications for solder deposition with irregular stencil apertures need to be adjusted. Originality/value – To address the arbitrariness of existing industry practice, this study was a joint effort with a Taiwan-based electronics manufacturing service company. Real data were taken from a mass production environment and inferences were then made based on a statistical analysis

Publisher: National Taipei University

Conquering SMT Stencil Printing Challenges with Today's Miniature Components

Jun 12, 2023 | Robert F. Dervaes, Jeff Poulos, Scott Williams

The technological advancement of component and PCB technology from through-hole to surface mount (SMT) is a major factor in the miniaturization of today's electronics. Smaller and smaller component sizes and more densely packed PCBs lead to more powerful designs in much smaller product packages. With advancement, however, comes a new set of challenges in building these smaller, more complex assemblies. This is the challenge original equipment manufacturers (OEM) and contract manufacturers (CM) face today....

Publisher: Fine Line Stencil, Inc.

Additive Manufacturing Technologies

Jun 02, 2023 | K. Srinivasulu Reddy & Solomon Dufera

Additive manufacturing (AM) is a latest technology that could improve manufacturing process by building up thin layers of materials from digitized three-dimensional (3D) designs virtually constructed using advanced CAD software. This technique affords the creation of new types of object with unique material properties. But while AM is widely billed as ‘the next industrial revolution’, in reality there are still significant hurdles for successful commercialisation of the technologies. This paper aims to provide a comprehensive review of literature, technologies and manufacturing practices on modern Additive Manufacturing.

Publisher: Adama Science and Technology University

Combining 3D Printing And Printable Electronics

Jun 02, 2023 | John Sarik, James Scott, Alex Butler, Steve Hodges, Nicolas Villar

A platform that enables the integration of conductive traces and printed three dimensional mechanical structures has been developed. We discuss the development of the platform and address issues that arise when combining 3D printing and printable electronics. We demonstrate a rapid prototyped three dimensional conductive trace and propose future applications for the platform.

Publisher: Columbia University

3-D Printed Electronics Additively Manufactured Electronics (AME)

Jun 02, 2023 | Nano Dimension

This presentation of Nano Dimension Ltd. (the"Company") contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act and other securities laws. Words such as "expects," "anticipates, " "intends, " "plans, " "believes, " "seeks, " "estimates" and similar expressions or variations of such words are intended to identify forward-looking statements. For example, the Company is using forward-looking statements when it discuss the potential of its products, strategic growth plan, its business plan and investment plans, the size fits addressable market, market growth, and expected recurring revenue growth. Forward-looking statements are no historical facts, and are based upon management's current expectations, beliefs and projections, many of which, by their nature, are inherently uncertain. Such expectations, beliefs and projections are expressed in good faith. However, there can be assurance that management's expectations, beliefs and projections will be achieved, and actual results may differ materially from what is expressed in or indicated by the forward-looking statements. Forward-looking statements are subject to risks and uncertainties that could cause actual performance or results to differ materially from those expressed in the forward-looking statements. For a more detailed description of the risks and uncertainties affecting the Company, reference is made to the Company's reports filed from time to time with the Securities and Exchange Commission ("SEC"), including, but not limited to, the risks detailed in the Company's annual report for the year ended December 31st, 2020, filed with the SEC. Forward-looking statements speak only as of the date the statements are made. The Company assumes no obligation to update forward-looking statements to reflect actual results, subsequent events or circumstances, changes in assumptions or changes in other factors affecting forward-looking information except to the extent required by applicable securities laws. If the Company does update one or more forward-looking statements, no inference should be drawn that the Company will make additional updates with respect thereto or with respect to other forward-looking statements....

Publisher: Nano Dimension

Conformal Coating of Thin Polymer Electrolyte Layer on Nanostructured Electrode Materials for Three-Dimensional Battery Applications

Jun 02, 2023 | Sanketh R. Gowda, Arava Leela Mohana Reddy, Manikoth M. Shaijumon, Xiaobo Zhan, Lijie Ci, and Pulickel M. Ajayan

Various three-dimensional (3D) battery architectures have been proposed to address effective power delivery in micro/ nanoscale devices and for increasing the stored energy per electrode footprint area. One step toward obtaining 3D configurations in batteries is the formation of core-shell nanowires that combines electrode and electrolyte materials. One of the major challenges however in creating such architectures has been the coating of conformal thin nanolayers of polymer electrolytes around nanostructured electrodes. Here we show conformal coatings of 25-30 nm poly(methyl methacralate) electrolyte layers around individual Ni-Sn nanowires used as anodes for Li ion battery. This configuration shows high discharge capacity and excellent capacity retention even at high rates over extended cycling, allowing for scalable increase in areal capacity with electrode thickness. Our results demonstrate conformal nanoscale anode-electrolyte architectures for an efficient Li ion battery system.

Publisher: Rice University

3D Printed Electronics

Jun 02, 2023 | M. Bowa, M. E. Dean, and R.D. Horn

Additive manufacturing is revolutionizing the way we build and produce a plethora of products spanning many industries. It has shown strong potential in reduced energy use, sustainability and cost effectiveness. Exploring avenues that this technology can be utilized is key to improve productivity and efficiencies in various applications including electronic systems and devices manufacturing. Electronic systems and sub-systems are built using a variety of material and processes, which require a large carbon footprint, significant waste material and high production time. We propose the application of 3D printing technology to support an integrative process for combining circuit board fabrication, solder mask process, electronic component pick and place and enclosure manufacturing. The integration of these separate processes into a single high efficiency additive manufacturing process will yield significant savings in energy use, carbon footprint, waste product and production time and cost.

Publisher: University of Tennessee

A Manufacturing Process For An Energy Storage Device Using 3D Printing

Jun 02, 2023 | Anan Tanwilaisiri, Ruirong Zhang, Yanmeng Xu, David Harrison and John Fyson

3D printing has been widely applied in the development of prototypes. The main advantage of this process is that the objects or products can be viewed in three dimensions on a computer display and a 3D sample can be created before committing to a large production run. There are various 3D printing technologies that are capable of manufacturing metal, ceramic, plastic substrate and paste objects. Recently several research groups have focused on the fabrication freedom of 3D printing for different purposes including freeform manufacturing of electrochemical devices but this use is still limited. This paper describes a manufacturing process for electrochemical supercapacitors using the combination of the two techniques of 3D printing which are Fused Deposition Modelling (FDM) and a Paste Extrusion system. The method relies on creating a frame for the energy storage device, i.e. supercapacitor, by the FDM 3D printer and then depositing the conductive layers and electrodes of the supercapacitor using Paste Extrusion system. A 3D supercapacitor has been made and evaluated in this study.

Publisher: Brunel University London

Additive Manufacturing – A Sustainable Manufacturing Route

Jun 02, 2023 | Domnita Fratila and Horatiu Rotaru

Additive Manufacturing (AM) technologies allow developing and manufacturing very complex shaped parts and functional products with a high level of customization, being a great alternative to Traditional Manufacturing (TM) methods like injection molding, die-casting or machining. Due to the importance of cleaner production in the field of manufacturing processes, sustainability of AM processes needs to be assessed in order to make easier its acceptance and implementation in the industry. Furthermore, the manufacturers can improve their competitiveness and profitability by considering the ecological aspects during the manufacturing step of a product. This paper gives a survey on sustainability issues related to AM.

Publisher: Technical University of Cluj-Napoca

3D-Printing And Advanced Manufacturing For Electronics

Jun 02, 2023 | Alejandro H. Espera Jr., John Ryan C. Dizon, Qiyi Chen, Rigoberto C. Advincula

Printed electronics currently holds a significant share in the electronics fabrication market due to advantages in high-throughput production and customizability in terms of material support and system process. The printing of traces and interconnects, passive and active components such as resistors, capacitors, inductors, and application-specific electronic devices, have been a growing focus of research in the area of additive manufacturing. Adaptation of new 3D-printing technologies and manufacturing methods, specifically for printed electronics, are potentially transformative in flexible electronics, wireless communications, efficient batteries, solid-state display technologies, etc. Other than printing new and reactive functional electronic materials, the functionalization of the printing substrates with unusual geometries apart from the conventional planar circuit boards will be a challenge. Building the substrate, printing the conductive tracks, pick-and-placing or embedding the electronic components, and interconnecting them, are fundamental fabrication protocols new 3D-printing systems should adopt for a more integrated fabrication. Moreover, designers and manufacturers of such systems will play an important role in scaling 3D-printed electronics from prototyping to high-throughput mass production. This review gives a groundwork for such understanding, defining methods and protocols, reviewing various 3D-printing methods, and describing the state-of- the-art in 3D-printed electronics and their future growth.

Publisher: Case Western Reserve University

3D Printing Electronic Components And Circuits With Conductive Thermoplastic Filament

Jun 02, 2023 | Patrick F. Flowers, Christopher Reyes, Shengrong Ye, Myung Jun Kim, Benjamin J. Wiley

This work examines the use of dual-material fused filament fabrication for 3D printing electronic components
and circuits with conductive thermoplastic filaments. The resistivity of traces printed from
conductive thermoplastic filaments made with carbon-black, graphene, and copper as conductive fillers
was found to be 12, 0.78, and 0.014 ohm cm, respectively, enabling the creation of resistors with values
spanning 3 orders of magnitude. The carbon black and graphene filaments were brittle and fractured
easily, but the copper-based filament could be bent at least 500 times with little change in its resistance.
Impedance measurements made on the thermoplastic filaments demonstrate that the copper-based filament
had an impedance similar to a copper PCB trace at frequencies greater than 1 MHz. Dual material
3D printing was used to fabricate a variety of inductors and capacitors with properties that could be
predictably tuned by modifying either the geometry of the components, or the materials used to fabricate
the components. These resistors, capacitors, and inductors were combined to create a fully 3D
printed high-pass filter with properties comparable to its conventional counterparts. The relatively low
impedance of the copper-based filament enabled its use for 3D printing of a receiver coil for wireless
power transfer. We also demonstrate the ability to embed and connect surface mounted components in
3D printed objects with a low-cost ($1000 in parts), open source dual-material 3D printer. This work thus
demonstrates the potential for FFF 3D printing to create complex, three-dimensional circuits composed
of either embedded or fully-printed electronic components.

Publisher: Duke University

Preparation and Properties of Graphite/Epoxy Resin Conductive Composites

May 30, 2023 | Shan-Shan Yao, Di Jiang, Qi-Zhong Zhang, Xin-Xin Wang

Graphite / epoxy resin conductive composites were prepared by mixing and molding process, using graphite and epoxy resin as raw materials, filling carbon fiber cloth and mixing a small amount of metal powder. We investigated effects on the different ratio of graphite raw materials and the amount of carbon fiber cloth and different metal powder on the resistance and bending strength of graphite / epoxy resin conductive composites. The optimum ratio of raw materials was determined by the experiment. The results showed that the electrical and mechanical properties of the composites were good when the ratio of the two kinds of graphite was 1:1, filling two layers of carbon fiber cloth and the content of aluminum powder was 1%. The resistivity was up to 0.0800 ohm cm, and the bending strength was up to 47.32MPa.

Publisher: Jilin Institute of Chemical Technology

Improvement of the Electrical-Mechanical Performance of Epoxy/Graphite Composites Based on the Effects of Particle Size and Curing Conditions

May 30, 2023 | Hendra Suherman , Radwan Dweiri, Abu Bakar Sulong, Mohd Yusuf Zakaria and Yovial Mahyoedin

This study aims to improve the electrical-mechanical performance of traditional epoxy/graphite composites for engineering applications. The improvement in the properties of these composites depended on the incorporation of different sizes of graphite particles of the same type and controlling their curing process conditions. The thermal properties andmicrostructural changeswere also characterized. A maximum in-plane electrical conductivity value of approximately 23 S/cm was reported for composites containing 80 wt.% G with a particle size of 150 _m. The effect of combining large and small G particles increased this value to approximately 32 S/cm by replacing the large particle size with 10 wt.% smaller particles (75 _m). A further increase in the electrical conductivity to approximately 50 S/cmwas achieved due to the increase in curing temperature and time. Increasing the curing temperature or time also had a crucial role in improving the tensile strength of the composites and a tensile strength of ~19MPa was reported using a system of multiple filler particle sizes processed at the highest curing temperature and time compared to ~9 MPa for epoxy/G150 at 80 wt.%. TGA analysis showed that the composites are thermally stable, and stability was improved by the addition of filler to the resin. A slight difference in the degraded weights and the glass transition temperatures between composites of different multiple filler particle sizes was also observed from the TGA and DSC results.

Publisher: Universitas Bung Hatta

Improved Heat-Spreading Properties Of Fluorinated Graphite/ Epoxy Film

May 30, 2023 | Kyung Hoon Kim, Jeong-In Han, Da-Hee Kang, and Young-Seak Lee

The use of electronic devices has rapidly increased, and such devices are required to be smaller, thinner, lighter, and with higher energy densities than ever before. These requirements can result in the generation of additional heat during device operation, and this heat has detrimental effects on performance, stability, running rate, and lifespan. For instance, if the temperature of an electronic device increases by 2oC when the operating temperature is higher than the stable operating temperature, the stability of the device will be reduced by 10% [1-3]. Thus, the additional heat that such devices generate must be spread to the surrounding environment via heat sinks, coatings, or films with high thermal conductivity.

The use of coatings and films is an appropriate approach for improving the heat spread in electronic devices, particularly as these devices become lighter, smaller, and thinner. Such coatings and films are typically based on polymers such as epoxy, acryl, and polyurethane. Due to the low thermal conductivity of these polymers, it is difficult to use this approach to achieve effective heat spreading. To solve this problem, a great deal of research has addressed the addition of fillers with high thermal conductivity, such as aluminum nitride [4,5], silica (SiO2), alumina (Al2O3), boron nitride [1,6,7], graphite [8], expanded graphite (EG) [9-11], carbon nanotubes (CNTs) [11-13], graphene [9,14,15], and graphene oxide (GO) to polymer-based coatings. Recently, carbon-based materials such as graphite, EG, CNTs, graphene, and GO have been widely investigated because of their low density and high thermal conductivity. However, CNTs and graphene are not appropriate for large-scale applications due to their high production cost and complex processing. In addition, fillers with poor dispersive stability aggregate in coatings form voids, resulting in the degradation of thermal conductivity [16,17]. In this study, anionic fluorine functional groups are introduced into a graphite surface via direct fluorination to increase dispersive stability by generating electrostatic repulsion. We expect the enhanced dispersive stability of the modified graphite to lead to the formation of fewer voids, resulting in improved thermal conductivity of the prepared heat-spreading film.

Publisher: Chungnam National University