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Article
Publication date: 7 November 2016

Teija Laine-Ma, Pekka Ruuskanen, Satu Pasanen and Mikko Karttunen

The aim of this study was to evaluate the feasibility of pad printing for producing electrical conductors and to define the factors affecting the print quality of polymeric silver…

Abstract

Purpose

The aim of this study was to evaluate the feasibility of pad printing for producing electrical conductors and to define the factors affecting the print quality of polymeric silver ink conductors.

Design/methodology/approach

Polyethylene terephthalate (PET) film and polyphenylene oxide (PPO) compound film were used as substrate materials. Three different polymeric silver inks, marked A, B and C, were used and tested.

Findings

The results indicated that the important factors in the pad printing of silver ink conductors are the printing parameters and characteristics of the ink, pad, cliché and substrate. The interactions of these factors should be considered on a case-by-case basis. The sheet resistances of triple-pressed ink conductors varied between 20 and 110 mΩ/sq for 5.7- to 8.5-μm-thick conductors. Ink (B) had a higher sheet resistance than Ink (A) because of its lower silver particle content but also because of the shorter curing time and lower curing temperature. Ink (A) showed excellent adhesion on PET, and Ink (B) had moderate adhesion on PET without corona or plasma pre-treatments, but both inks adhered weakly on PPO compound. Both corona and plasma treatments raised adhesion of these two inks on all test substrates to the highest classification value, 5B.

Originality/value

This paper contains a survey and preliminary testing of the pad printing of polymeric silver ink conductors on flexible thermoplastic foils. Finally, the paper introduces the advantages and drawbacks of the technique.

Details

Circuit World, vol. 42 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 20 November 2009

Teija Laine‐Ma, Pekka Ruuskanen, Satu Kortet and Mikko Karttunen

The adhesion between electroless copper and a substrate is one of the most important factors in the reliability of thermoplastic printed circuit boards. The purpose of this paper…

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Abstract

Purpose

The adhesion between electroless copper and a substrate is one of the most important factors in the reliability of thermoplastic printed circuit boards. The purpose of this paper is to investigate the effects of mechanical grinding and acid etching of thermoplastic substrate materials on the adhesion of copper deposited by an electroless copper plating process. The base material of the test substrates was a new high temperature thermoplastic polyphenylene oxide (PPO) compound.

Design/methodology/approach

The effects of pre‐treatment on plastic surfaces are analyzed by the following methods: Fourier transform infrared (FTIR), SEM, the Dyne surface energy test and the surface roughness test. The adhesion between electroless copper and thermoplastic substrate is measured with a peel strength test.

Findings

The results showed that mechanical grinding of the substrates significantly increased adhesion but the highest adhesion is gained by using an acid etch treatment before electroless plating. These results indicated that adhesion between copper and the substrates was not directly proportional to the roughness and surface energy values.

Originality/value

The conventional sweller/desmear treatment used in a printed circuit board factory for pre‐treating epoxy based laminates prior to electroless plating is not suitable for these PPO compound boards. The copper adhesion is adequate when the substrates are etched with sulphuric acid/chromate solution. In that case the bonding between the metal layer and the plastic surface is stronger than the bondings between the polymer chains of the thermoplastic material. The adhesion mechanism of electroless copper in these mechanically abraded samples is mechanical interlocking of metal particles.

Details

Circuit World, vol. 35 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 28 October 2014

Teija Laine-Ma, Pekka Ruuskanen, Satu Pasanen and Mikko Karttunen

The aim of this study was to test and survey a circuitry transfer technique where conductor patterns are electroformed on carrier substrates and thereafter the electroformed…

Abstract

Purpose

The aim of this study was to test and survey a circuitry transfer technique where conductor patterns are electroformed on carrier substrates and thereafter the electroformed patterns are transferred from carrier substrates to their final devices.

Design/methodology/approach

An electrically conductive pattern is built up by an electrodepositing metal or metal alloy on a carrier substrate, called a mandrel, using a resist image to define the outlines of the pattern. Thereafter, the electroformed structures are bonded on plastic substrates, for instance, by hot pressing or by embedding into a resin. In our experiments, the imaging of stainless steel carriers was done by the photolithographic process and the electroformed copper patterns were transferred by hot pressing onto thermoplastic substrates.

Findings

The literature review revealed that the transfer of electroformed conductor patterns to plastic parts is not a very commonly used technology, although it could provide possibilities for even quite specific structures in electronics manufacturing at an affordable price. Our tests indicated that the acidic peroxide-sulfuric pre-treatment of electroformed copper patterns before hot press bonding clearly improved the adhesion of copper on both acrylonitrile butadiene styrene and polyphenylene oxide substrates and that a steel template around the substrate during hot pressing process can restrict dimensional changes in thermoplastic substrates significantly.

Originality/value

This paper contains a survey and preliminary testing of the electroformed circuitry transfer technique. The analysis of the test boards focused on the adhesion between copper strips and thermoplastic substrates and on the factors affecting adhesion. Finally, the paper introduces the advantages and drawbacks of the technique.

Details

Circuit World, vol. 40 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 25 January 2011

Sari Merilampi, Toni Björninen, Leena Ukkonen, Pekka Ruuskanen and Lauri Sydänheimo

The purpose of this paper is to develop a wireless strain sensor for measuring large strains. The sensor is based on passive ultra high‐frequency radio frequency identification…

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Abstract

Purpose

The purpose of this paper is to develop a wireless strain sensor for measuring large strains. The sensor is based on passive ultra high‐frequency radio frequency identification (RFID) technology and it can be embedded into a variety of structures.

Design/methodology/approach

Silver ink conductors and RFID tags were printed by the screen printing method on stretchable polyvinyl chloride and fabric substrates. The development of the strain‐sensitive RFID tag was based on the behavior of the selected antenna and substrate materials. Performance of the tags and the effect of mechanical strain on tag functioning were examined.

Findings

The results showed that large displacements can be successfully measured wirelessly using a stretchable RFID tag as a strain‐sensitive structure. The behavior of the tag can be modified by selection of the material.

Research limitations/implications

New tag designs, which are more sensitive to small levels of strain and which have a linear response will be the subject for future work. Tag performance under cyclic loading and in a real environment will also be investigated. Future work relating the investigation of practical applications and the system designing for the strain sensor will also be required.

Practical implications

Printing is fast and simple manufacturing process which does not produce much waste or material loss. The sensor is a new application of printed electronics. It also provides new opportunities for system designers.

Originality/value

The paper provides a new kind of wireless strain sensor which can be integrated into many structures (i.e. clothes). The sensor is a new application of printed electronics and it is made from novel materials.

Details

Sensor Review, vol. 31 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Book part
Publication date: 27 November 2014

Jacques Defourny and Victor Pestoff

There is still no universal definition of the third sector in Europe, but it can be seen as including all types of non-governmental not-for-profit entities such as non-profit…

Abstract

There is still no universal definition of the third sector in Europe, but it can be seen as including all types of non-governmental not-for-profit entities such as non-profit organizations, mutuals, cooperatives, social enterprises and foundations. This article attempts to make sense of the current shifting conceptualization of the third sector in Europe. It is based on short country summaries of the images and concepts of the third sector in 13 European countries by EMES Network’s members, first presented in 2008 (Defourny and Pestoff, 2008; nine of them were recently revised and are found in the appendix to this article.). The perception and development of the third sector in Europe is closely related to the other major social governance institutions/mechanisms, like the market, state and community and through the third sector’s interaction with them. Moreover, many third sector organizations (TSOs) overlap with these other social institutions, resulting in varying degrees of hybridity and internal tensions experienced by them. TSOs can generate resources from their activities on the market, by providing services in partnership with the state and/or by promoting the interests of a given community or group. The country overviews document a growing professionalization of TSOs in most countries and a growing dependency of public funds to provide services. This has important theoretical and practical implications for orienting the articles included in this book. Thus, it can provide a key for better understanding the discussion and analysis in the remainder of this volume.

Details

Accountability and Social Accounting for Social and Non-Profit Organizations
Type: Book
ISBN: 978-1-78441-004-9

Keywords

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