Project Outline: Laser activation of printed metal-polymer composites (LaMP)

Research Objective

Creation of a continuous metallic structure on the surface of printed metal-polymer composites, thus increasing the electrical conductivity of the printed composite structure.

• Formulation of printable metal-polymer composites (thick film), which can be processed both by digital and mask-based printing processes
• Adjustment of the functionality of the printed structures by laser processing
• Processability of oxidation-sensitive materials by laser-based sintering process
• Usability of substrates with limited temperature resistance by laser-based sintering process

Desired Research Results

• Extension of the available spectrum of printable metallic pastes by pure element pastes (e.g. copper) and special alloying material pastes (e.g. CuNiMn)
• Significant improvement of the properties of currently available pastes through laser post-treatment

Innovative Contribution of the Intended Research Results

• Extension of the thick film printing technology towards new metal powder alloys and temperature sensitive base substrates
• Establishment of the laser-based sintering process for printed thick-film electronics
• Unification of printing technology and sintering processes in plant engineering for the production of 3D components

Solution to Achieve the Research Objective

Two approaches are being pursued with regard to the laser-based sintering process:

• One-step process: energy input is sufficient to decompose the polymer and sinter the metallic component in the same processing step
• Two-stage process: Energy input is first selected so that the polymer matrix is decomposed. In the second processing step, sintering of the metallic components takes place with a higher energy input

Variation of the metallic particles in the printed pastes:

• Influences of morphology on sintering behaviour
• Influences of the mixture of micro- and nanoscale powder mixtures on sintering behaviour

1. Preparation and characterization of metal-polymer composites
2. Printing on temperature sensitive substrates
3. Laser processing of metal-polymer composites
4. Establishment of laser manufacturing processes
5. Characterization after laser processing
6. Demonstrator production
7. Documentation

Feasibility and Transfer of the Results

An economic benefit for the companies, especially for SMEs and the companies involved in the Project Accompanying Committee, arises in the following areas:

• the chosen production technologies (screen printing, dispensing technology, laser system) are all suitable for mass production – low-cost industrial application suitable for mass production
• all the technologies used are already established, so that the market is broadly diversified with manufacturers of the various technologies used and good performance-related availability of equipment is ensured
• The additive manufacturing approach represents a major advantage with regard to a sustainable energy and resource-saving manufacturing technology
• Relevance of the topic is to be communicated to the general public through publications in application-oriented and scientific journals, as well as through lectures at relevant events
• Holding workshops of the participating institutes in order to present the findings to a specialist audience

Expected Use of the Intended Research Results in SMEs

Development of new products / improvement of existing products, e.g:

• Increasing the maximum electrical power transmission of printed conductors
• Optimization of resistive PT temperature sensors on PET substrate
• Development of new technologies: printed thermocouples on PET substrate

Expected Contribution to Increasing the Competitiveness of SMEs

• Expansion of the material portfolio of metallic pastes to include special alloy materials in order to open up new areas of application for printed, conductive functional structures in a wide range of industries
• Extension of the usable (temperature sensitive) basic substrates
• Use of the laser-induced sintering process enables the processing of oxidation-sensitive alloy materials by printing
• Improvement of the electrical properties of existing paste materials (e.g. silver pastes) enables new applications
• Direct typographic functionalization of 3D components

Expected Industrial Implementation of the R&D Results after the End of the Project

• improved individual components and systems in terms of energy efficiency, heat losses and increased integrability
• new materials enable additional applications in the field of printed electronics, e.g. sensors (temperature, force, gas detection) or actuators (heating structures, switches)

Research institutions

IFAM – Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research

Head of the research institution: Prof. Dr.-Ing. M. Busse

matthias.busse@ifam.fraunhofer.de

Vienna Str. 12
28359 Bremen, GER

BIAS – Bremen Institute for Applied Beam Technology GmbH

Head of the research institution: Prof. Dr.-Ing. F. Vollertsen

info-mbs@bias.de

Klagenfurter Str. 5
28359 Bremen, GER

Figure: Printed thermocouples on various high-temperature substrates; Source: Fraunhofer IFAM