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Advanced Manufacture by Screen Printing / SARAH POTTS

Swansea University Author: SARAH POTTS

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DOI (Published version): 10.23889/SUthesis.58460

Abstract

Screen-printing is the most widely used process in printed electronics, due to its ability to transfer materials with a wide range of functional properties at high thickness and solid loading. However, the science of screen printing is still rooted in the graphics era, with limited understanding of...

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Published: Swansea 2021
Institution: Swansea University
Degree level: Doctoral
Degree name: EngD
Supervisor: Claypole, Tim C. ; Phillips, Chris O.
URI: https://cronfa.swan.ac.uk/Record/cronfa58460
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first_indexed 2021-10-26T10:40:21Z
last_indexed 2021-10-27T03:23:57Z
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fullrecord <?xml version="1.0"?><rfc1807><datestamp>2021-10-26T12:00:18.1687779</datestamp><bib-version>v2</bib-version><id>58460</id><entry>2021-10-26</entry><title>Advanced Manufacture by Screen Printing</title><swanseaauthors><author><sid>0fedbed95b1e941d809c5ecddf7b4080</sid><firstname>SARAH</firstname><surname>POTTS</surname><name>SARAH POTTS</name><active>true</active><ethesisStudent>false</ethesisStudent></author></swanseaauthors><date>2021-10-26</date><abstract>Screen-printing is the most widely used process in printed electronics, due to its ability to transfer materials with a wide range of functional properties at high thickness and solid loading. However, the science of screen printing is still rooted in the graphics era, with limited understanding of the fundamental science behind the ink transfer process. A multifaceted approach encompassing all aspects of the production of printed electronics from ink formulation, through screen-printing and post processing was therefore undertaken. With a focus on carbon inks due to their electrical conductivity, low cost, inertness and ability to be modified or functionalised. Parametric studies found that with blade squeegees, lower angles and softer blades led to increases in ink deposition, irrespective of ink rheology. However, the effects of print speed and snap distance were related to the rheology of the inks. Existing computational models were inaccurate and based on two contrasting theories. Extensional CaBER testing provided qualitative indications of the effect of separation speed and distance on deposition. However, this could only assess the effect of vertical, 2-dimensional forces and could not evaluate the influence of shear forces due to separation angle or the effects of the screen mesh. For this purpose, a screen-printing visualisation rig was specifically constructed, allowing the ink transfer mechanism to be captured for the first time. This identified similarities with one of the two theories, although existing models had oversimplified the process and did not account for variations in lengths of the separation regions or the contact angle between the mesh and substrate. It was also found that changes in the ink rheology and parameter settings changes the lengths of these regions, as well as the shape and presence of filaments formed during separation. The parameters of print speed, snap distance, solid loading and ink rheology were assessed and found to affect the mesh/substrate contact time and filamentation behaviour. This had a quantifiable effect on ink deposition, in terms of the amount of ink transfer, roughness and therefore conductivity. Finally, photonic annealing and subsequent compression rolling were found to enhance the conductivity of carbon inks by removing binder between particles and consolidating the ink film, leading to 8 times reduction in resistivity for a graphite-based ink and halving in resistivity for an ink containing a combination of carbon black and graphite, where there was less potential for improvement due to the conductive bridges between the graphite flakes.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords>Materials Engineering, Printed Electronics</keywords><publishedDay>26</publishedDay><publishedMonth>10</publishedMonth><publishedYear>2021</publishedYear><publishedDate>2021-10-26</publishedDate><doi>10.23889/SUthesis.58460</doi><url/><notes>ORCiD identifier http://orcid.org/0000-0003-0208-2364</notes><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><supervisor>Claypole, Tim C. ; Phillips, Chris O.</supervisor><degreelevel>Doctoral</degreelevel><degreename>EngD</degreename><degreesponsorsfunders>Engineering and Physical Sciences Research Council (EPSRC), European Social Fund, Coated2 and icm Print; Grant number - EP/L015099/1</degreesponsorsfunders><apcterm/><lastEdited>2021-10-26T12:00:18.1687779</lastEdited><Created>2021-10-26T11:37:14.4479953</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Uncategorised</level></path><authors><author><firstname>SARAH</firstname><surname>POTTS</surname><order>1</order></author></authors><documents><document><filename>58460__21304__459b00c9f15b483eabf20b9ac3ab8438.pdf</filename><originalFilename>Potts_Sarah_Jane_EngD_Thesis_Redacted_Signature.pdf</originalFilename><uploaded>2021-10-26T11:52:49.8066962</uploaded><type>Output</type><contentLength>6648737</contentLength><contentType>application/pdf</contentType><version>E-Thesis &#x2013; open access</version><cronfaStatus>true</cronfaStatus><documentNotes>Copyright: The author, Sarah-Jane Potts, 2020.</documentNotes><copyrightCorrect>true</copyrightCorrect><language>eng</language></document></documents><OutputDurs/></rfc1807>
spelling 2021-10-26T12:00:18.1687779 v2 58460 2021-10-26 Advanced Manufacture by Screen Printing 0fedbed95b1e941d809c5ecddf7b4080 SARAH POTTS SARAH POTTS true false 2021-10-26 Screen-printing is the most widely used process in printed electronics, due to its ability to transfer materials with a wide range of functional properties at high thickness and solid loading. However, the science of screen printing is still rooted in the graphics era, with limited understanding of the fundamental science behind the ink transfer process. A multifaceted approach encompassing all aspects of the production of printed electronics from ink formulation, through screen-printing and post processing was therefore undertaken. With a focus on carbon inks due to their electrical conductivity, low cost, inertness and ability to be modified or functionalised. Parametric studies found that with blade squeegees, lower angles and softer blades led to increases in ink deposition, irrespective of ink rheology. However, the effects of print speed and snap distance were related to the rheology of the inks. Existing computational models were inaccurate and based on two contrasting theories. Extensional CaBER testing provided qualitative indications of the effect of separation speed and distance on deposition. However, this could only assess the effect of vertical, 2-dimensional forces and could not evaluate the influence of shear forces due to separation angle or the effects of the screen mesh. For this purpose, a screen-printing visualisation rig was specifically constructed, allowing the ink transfer mechanism to be captured for the first time. This identified similarities with one of the two theories, although existing models had oversimplified the process and did not account for variations in lengths of the separation regions or the contact angle between the mesh and substrate. It was also found that changes in the ink rheology and parameter settings changes the lengths of these regions, as well as the shape and presence of filaments formed during separation. The parameters of print speed, snap distance, solid loading and ink rheology were assessed and found to affect the mesh/substrate contact time and filamentation behaviour. This had a quantifiable effect on ink deposition, in terms of the amount of ink transfer, roughness and therefore conductivity. Finally, photonic annealing and subsequent compression rolling were found to enhance the conductivity of carbon inks by removing binder between particles and consolidating the ink film, leading to 8 times reduction in resistivity for a graphite-based ink and halving in resistivity for an ink containing a combination of carbon black and graphite, where there was less potential for improvement due to the conductive bridges between the graphite flakes. E-Thesis Swansea Materials Engineering, Printed Electronics 26 10 2021 2021-10-26 10.23889/SUthesis.58460 ORCiD identifier http://orcid.org/0000-0003-0208-2364 COLLEGE NANME COLLEGE CODE Swansea University Claypole, Tim C. ; Phillips, Chris O. Doctoral EngD Engineering and Physical Sciences Research Council (EPSRC), European Social Fund, Coated2 and icm Print; Grant number - EP/L015099/1 2021-10-26T12:00:18.1687779 2021-10-26T11:37:14.4479953 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised SARAH POTTS 1 58460__21304__459b00c9f15b483eabf20b9ac3ab8438.pdf Potts_Sarah_Jane_EngD_Thesis_Redacted_Signature.pdf 2021-10-26T11:52:49.8066962 Output 6648737 application/pdf E-Thesis – open access true Copyright: The author, Sarah-Jane Potts, 2020. true eng
title Advanced Manufacture by Screen Printing
spellingShingle Advanced Manufacture by Screen Printing
SARAH POTTS
title_short Advanced Manufacture by Screen Printing
title_full Advanced Manufacture by Screen Printing
title_fullStr Advanced Manufacture by Screen Printing
title_full_unstemmed Advanced Manufacture by Screen Printing
title_sort Advanced Manufacture by Screen Printing
author_id_str_mv 0fedbed95b1e941d809c5ecddf7b4080
author_id_fullname_str_mv 0fedbed95b1e941d809c5ecddf7b4080_***_SARAH POTTS
author SARAH POTTS
author2 SARAH POTTS
format E-Thesis
publishDate 2021
institution Swansea University
doi_str_mv 10.23889/SUthesis.58460
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
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description Screen-printing is the most widely used process in printed electronics, due to its ability to transfer materials with a wide range of functional properties at high thickness and solid loading. However, the science of screen printing is still rooted in the graphics era, with limited understanding of the fundamental science behind the ink transfer process. A multifaceted approach encompassing all aspects of the production of printed electronics from ink formulation, through screen-printing and post processing was therefore undertaken. With a focus on carbon inks due to their electrical conductivity, low cost, inertness and ability to be modified or functionalised. Parametric studies found that with blade squeegees, lower angles and softer blades led to increases in ink deposition, irrespective of ink rheology. However, the effects of print speed and snap distance were related to the rheology of the inks. Existing computational models were inaccurate and based on two contrasting theories. Extensional CaBER testing provided qualitative indications of the effect of separation speed and distance on deposition. However, this could only assess the effect of vertical, 2-dimensional forces and could not evaluate the influence of shear forces due to separation angle or the effects of the screen mesh. For this purpose, a screen-printing visualisation rig was specifically constructed, allowing the ink transfer mechanism to be captured for the first time. This identified similarities with one of the two theories, although existing models had oversimplified the process and did not account for variations in lengths of the separation regions or the contact angle between the mesh and substrate. It was also found that changes in the ink rheology and parameter settings changes the lengths of these regions, as well as the shape and presence of filaments formed during separation. The parameters of print speed, snap distance, solid loading and ink rheology were assessed and found to affect the mesh/substrate contact time and filamentation behaviour. This had a quantifiable effect on ink deposition, in terms of the amount of ink transfer, roughness and therefore conductivity. Finally, photonic annealing and subsequent compression rolling were found to enhance the conductivity of carbon inks by removing binder between particles and consolidating the ink film, leading to 8 times reduction in resistivity for a graphite-based ink and halving in resistivity for an ink containing a combination of carbon black and graphite, where there was less potential for improvement due to the conductive bridges between the graphite flakes.
published_date 2021-10-26T04:15:00Z
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