Screen Printing Fine Pitch Stretchable Silver Inks onto a Flexible Substrate for Wearable Applications

2018 ◽  
Vol 15 (4) ◽  
pp. 179-186
Author(s):  
Jianbiao Pan ◽  
Malcolm Keif ◽  
Joshua Ledgerwood ◽  
Xiaoying Rong ◽  
Xuan Wang

Abstract This article presents the development and optimization of the screen printing process for printing stretchable silver ink onto a stretchable thermoplastic polyurethane substrate. A test vehicle was designed including 50 μm/5 mm (line width/line length) to 350 μm/35 mm lines (at four biases). A two-level factorial design with three replicates was selected to investigate the effect of process parameters on the quality of prints. We proposed calculated sheet resistance based on the measured resistance value, trace width, and trace length, which can replace trace height measurements on rough profile substrates. We found that squeegee pressure and emulsion thickness have statistically significant effects on calculated sheet resistance of print traces, whereas print speed does not have statistically significant effects. In our experiment setting levels, the lower the squeegee pressure, the lower the calculated sheet resistance that is achieved. The emulsion with higher emulsion over mesh (EOM) is better than the emulsion with lower EOM because it can achieve lower sheet resistance. After optimizing the screen printing process, we were able to print 100 μm (4 mils) trace width and spacing with high consistency.

2018 ◽  
Vol 2018 (1) ◽  
pp. 000665-000671
Author(s):  
Jianbiao Pan ◽  
Malcolm Keif ◽  
Joshua Ledgerwood ◽  
Xiaoying Rong ◽  
Xuan Wang

Abstract The lightweight and bendable features of printed flexible electronics are increasingly attractive. Currently stretchable silver inks are formulated for wide traces, typically larger than 2 mm. To attach ultra-thin silicon chips that have fine pitch onto printed organic substrate, it is necessary to print fine trace width/space that matches the pitch of the chips, which may be less than 200 microns. This paper presents the development and optimization of the screen printing process for printing stretchable silver ink onto stretchable thermoplastic polyurethane (TPU) substrate. A test vehicle was designed including 50 μm/5 mm (line width/line length) to 350 μm/35 mm lines (at 4 biases). The stretchable ink selected was DuPont PE 873 and Dupont's PE 5025 ink (non-stretchable conductive flake silver) was used as a “control” to baseline the printing process. The substrate used was Bemis TPU ST604. The experiment was done on a DEK Horizon 03i printer. A DEK squeegee 200 (Blue) and a DEK 265 flood bar (200 mm) were used. A 2-level factorial design with three replicates was selected to investigate the effect of process parameters on the quality of prints. The quality of the prints is characterized by 1) resistance of traces, 2) sheet resistance, 3) z-axis height, and 4) trace width/spacing. We observed significant noise in the z-axis printed silver ink height measured by profilometry and concluded z-axis height is not a good response variable for characterizing screen printing stretchable silver ink onto TPU substrate, mainly due to high roughness of the TPU substrate. We proposed calculated sheet resistance based on the measured resistance value, trace width, and trace length, which can replace trace height measurements on rough profile substrates. We found that squeegee pressure and emulsion thickness have statistically significant effects on calculated sheet resistance of print traces while print speed does not have statistically significant effects. In our experiment setting levels, the lower the squeegee pressure, the lower the calculated sheet resistance that is achieved. The emulsion with higher emulsion over mesh (EOM) is better than the emulsion with lower EOM since it can achieve lower sheet resistance. After optimizing the screen printing process, we were able to print 100 μm (4 mils) trace width and spacing with high consistency.


Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 803 ◽  
Author(s):  
Marcel Knoll ◽  
Christina Offenzeller ◽  
Bernhard Mayrhofer ◽  
Bernhard Jakoby ◽  
Wolfgang Hilber

This work deals with the realization of a fully printed thermocouple-array on a flexible substrate for condition monitoring applications. The thermocouple-array consisting of carbon black and silver was fabricated on PET-foil in a screen printing process and characterized up to a junction temperature of 150 °C. To ensure that no spurious voltages of the thermocouple occur due to deformations of the flexible substrate, the cross-sensitivity to deformation of the foil was investigated as well. Finally, as a test case, the temperature gradient of a plastic bar heated on a single end was measured with the thermocouple-array.


RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20550-20556
Author(s):  
Isao Shitanda ◽  
Kanako Oda ◽  
Noya Loew ◽  
Hikari Watanabe ◽  
Masayuki Itagaki ◽  
...  

Bio-composite inks based on magnesium oxide (MgO)-templated mesoporous carbon (MgOC) and chitosan cross-linked with genipin for one-step screen-printing process.


Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 474 ◽  
Author(s):  
Bei Wang ◽  
Manuel Baeuscher ◽  
Xiaodong Hu ◽  
Markus Woehrmann ◽  
Katharina Becker ◽  
...  

A novel capacitive sensor for measuring the water-level and monitoring the water quality has been developed in this work by using an enhanced screen printing technology. A commonly used environment-friendly conductive polymer poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) for conductive sensors has a limited conductivity due to its high sheet resistance. A physical treatment performed during the printing process has reduced the sheet resistance of printed PEDOT:PSS on polyethylenterephthalat (PET) substrate from 264.39 Ω/sq to 23.44 Ω/sq. The adhesion bonding force between printed PEDOT:PSS and the substrate PET is increased by using chemical treatment and tested using a newly designed adhesive peeling force test. Using the economical conductive ink PEDOT:PSS with this new physical treatment, our capacitive sensors are cost-efficient and have a sensitivity of up to 1.25 pF/mm.


2010 ◽  
Author(s):  
Aminreza Ahari Kaleibar ◽  
Mona Rahbar ◽  
Marius Haiducu ◽  
Ash M. Parameswaran

1999 ◽  
Author(s):  
Jianbiao Pan ◽  
Gregory L. Tonkay

Abstract 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.


2014 ◽  
Vol 1004-1005 ◽  
pp. 799-802 ◽  
Author(s):  
Chang Lang Chen ◽  
Yu Tung Chang ◽  
Sheng Hao Taso ◽  
Weichieh Hsu

The In-Mold Roller is a revolutionary printing process by which objects are 3D decorated. Products decorated by In-Mold Roller are waterproof and protected from fading. What’s more, these kinds of decorations strongly increase the beauty, desirability and value of the objects. The In-Mold Roller is now using either of gravure printing and screen printing to print PET film. However, there are some problems with these two techniques. This research is to investigate potential usages of combining In-Mold Roller with digital UV inkjet printing in 3D decoration, e.g. in personalized printing services. Study results found that when the coverage and the resolution of inkjet printing become higher, the SIDs will become higher as well. When transferred to ABS, SIDs in each combination will increase. Each combination of inkjet conditions, with the isolation of white ink, color differences are less variant. TVIs of white ink decrease 30% to 40% halftone and display in “M” type. In print contrast, C and K colors of each combination are better than M and Y colors. After transferred into print contrast, each combination of PC will be higher about 2 to5. When transferred to ABS, color variances of each combination are not huge, and color differences are about 3to5.


Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 713 ◽  
Author(s):  
Romana Daňová ◽  
Robert Olejnik ◽  
Petr Slobodian ◽  
Jiri Matyas

Wearable electronic sensor was prepared on a light and flexible substrate. The breathing sensor has a broad assumption and great potential for portable devices in wearable technology. In the present work, the application of a flexible thermoplastic polyurethane/multiwalled carbon nanotubes (TPU/MWCNTs) strain sensor was demonstrated. This composite was prepared by a novel technique using a thermoplastic filtering membrane based on electrospinning technology. Aqueous dispersion of MWCNTs was filtered through membrane, dried and then welded directly on a T-shirt and encapsulated by a thin silicone layer. The sensing layer was also equipped by electrodes. A polymer composite sensor is capable of detecting a deformation by changing its electrical resistance. A T-shirt was capable of analyzing a type, frequency and intensity of human breathing. The sensitivity to the applied strain of the sensor was improved by the oxidation of MWCNTs by potassium permanganate (KMnO4) and also by subsequent application of the prestrain.


2017 ◽  
Vol 8 (2) ◽  
pp. 11-17
Author(s):  
Viktoriya Korotka ◽  
◽  
Svitlana Havenko ◽  
Kseniya Bazylyuk ◽  
◽  
...  

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