Electronics Manufacturing Technical Articles

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

Electro-Conductive Resins Filled With Graphite For Casting Applications

May 30, 2023 | Igor Novak, Igor Krupa

Electro-conductive resins, convenient for casting and coating applications were investigated in this paper. Electrical conductivity of epoxy and polyurethane resins, filled with two different grades of synthetic graphite (different average size) was studied. It was found that all the investigated composites became electro-conductive when filled with 22-vol% of the filler. The impact strength of epoxy and polyurethane resins filled with graphite was also investigated. A decrease in impact strength with an increase in filler content was observed in all cases. The highest values of impact strength were found for polyurethane/graphite KS 6 composites. The strength of adhesion of the filled resins to aluminum was also determined. A decrease in the strength of adhesive joints to aluminum foils with an increase in filler content was observed in all cases. The strongest adhesive joints were found for the epoxy/graphite KS 6 composites.

Publisher: Slovak Academy of Sciences

Recent Progress On Thermal Conductivity Of Graphene Filled Epoxy Composites

May 30, 2023 | Ruicong Lv, Yanjuan Ren, Haichang Guo, Shulin Bai

With the rapid development of the electronic industry, the requirements for packaging materials with high thermal conductivity (TC) are getting higher and higher. Epoxy is widely used as package material for electronic package applications. But it's intrinsic TC can't meets the increasing demands. Adding high TC graphene into epoxy matrix is a proper way to reinforce epoxy composites. This review focuses on the filler modification, preparation process and thermal properties of graphene-filled epoxy resin composites. Different ways of covalent and non-covalent modification methods are discussed. The various kinds of graphene coating layer are also summarized. Then we analysis the hybrid filler system in epoxy composite. We hope this review will provide guidance for the development and application of graphene-filled epoxy resin composites.

Publisher: Peking University

在DPC陶瓷基板上如何做碳油厚膜电阻

May 23, 2023 | 斯利通

在DPC陶瓷基板上如何做碳油厚膜电阻...

Publisher: Folysky Technology(Wuhan)Co.,Ltd

QUANTIFYING THE IMPROVEMENTS IN THE SOLDER PASTE PRINTING PROCESS FROM STENCIL NANOCOATINGS AND ENGINEERED UNDER WIPE SOLVENTS

May 22, 2023 | Chrys Shea, Mike Bixenman, T.C. Loy, Debbie Carboni, Brook Sandy-Smith, Greg Wade, Ray Whittier, Joe Perault, Eric Hanson

Over the past several years, much research has been performed and published on the benefits of stencil nano-coatings and solvent under wipes. The process improvements are evident and well-documented in terms of higher print and end-of-line yields, in improved print volume repeatability, in extended under wipe intervals, and in photographs of the stencil's PCB-seating surface under both white and UV light. But quantifying the benefits using automated Solder Paste Inspection (SPI) methods has been elusive at best. SPI results using these process enhancements typically reveal slightly lower paste transfer efficiencies and less variation in print volumes to indicate crisper print definition. However, the improvements in volume data do not fully account for the overall improvements noted elsewhere in both research and in production....

Publisher: KYZEN Corporation

Nanocoating and SMT Stencils

May 22, 2023 | Tecan

With a thickness of no more than 1-100 nanometers, nanocoatings are ultra-thin layers or chemical structures that are applied to surfaces by a variety of methods and applied to a wide range of substrates and chemically bond with non-porous surfaces. To put this in perspective, consider the thickness of paint used in the automotive industry of which is typically 125 microns or 125,000 nanometers.
While they can be one molecule thick, multiple molecular layers can be built up to deliver a particular chemical or physical property to a surface such as water-resistance (hydrophobic) and oil-resistance (oleophobic).

Publisher: tecan

Nanocoatings Webinar & NanoClear® Stencil Treatment

May 22, 2023 | Edward Hughes, ChrysShea

Agenda Overview Independent Testing & Studies-Print studies -Understencil Wipe studies-Durability Testing-Ongoing Studies NanoClear Product Information NanocoatingsComparison Summary Questions...

Publisher: Aculon