Ingo Wirth | Fraunhofer IFAM: What is the absolute minimum thickness limit to prevent short circuits in printed screen-printed sensors?
00:08:32.035 - 00:09:21.775
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What is the absolute minimum thickness limit to prevent short circuits in printed screen-printed sensors?
A key design challenge in printed electronics is avoiding electrical shorts between overlapping conductor layers. In screen-printed piezoelectric sensors, the active piezo material itself acts as the isolating dielectric layer separating the top and bottom silver electrodes.
To guarantee electrical isolation during operation and subsequent high-voltage polarization, the printed active layer must meet a strict physical thickness threshold. Practical testing reveals that any thickness below this threshold significantly increases pinhole defects and short-circuit risks.
Specifically, Fraunhofer IFAM's research indicates that a minimum thickness of 100 microns is required. Maintaining this dimension ensures reliable insulating properties and consistent sensor capacitance across the entire array.
In this short video, you can learn:
* How the printed piezoelectric layer functions simultaneously as an active material and an insulating dielectric barrier.
* The minimum thickness threshold required to eliminate short-circuit failures in screen-printed electrode stacks.
* How to manage layer dimensions to ensure reproducible sensor capacitance.
📋 **Clip Abstract** During the Q&A session, Ingo Wirth discusses how to prevent short circuits between overlapping silver electrodes in printed sensors. He reveals that a minimum piezoelectric layer thickness of 100 microns is critical to maintaining electrical isolation.
#ScreenPrintedSensors, #PiezoelectricSensors, #DielectricIsolation, #PinholeDefects, #PrintedElectronics, #FlexibleElectronics
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00:02:03.505 - 00:03:18.565
How do you build and activate a screen-printed piezoelectric sensor directly on a composite panel?
How do you build and activate a screen-printed piezoelectric sensor directly on a composite panel?
Screen printing presents a promising route for embedding structural health monitoring directly into composite aeronautic structures. By depositing a three-layer stack consisting of a bottom silver electrode, a functional piezoelectric layer, and a top silver electrode, engineers can integrate thin, lightweight sensors with minimal impact on structural integrity.
The resulting printed sensor layer reaches a thickness of approximately 135 microns. However, after the screen-printing process is complete, the piezoelectric material remains unoriented and functionally inactive.
To activate the sensor, a post-print polarization process must be executed. This involves applying a high voltage across the top and bottom silver electrodes while simultaneously heating the entire sample, causing the individual piezoelectric crystals within the paste to align within the electromagnetic field.
In this short video, you can learn:
* The precise three-layer architecture used for printed structural health monitoring sensors.
* Why a 135-micron thickness profile is targeted for these screen-printed active layers.
* The thermal and electromagnetic polarization process required to align the piezoelectric crystals in the printed paste.
📋 **Clip Abstract** This clip details the material stack and fabrication flow for screen-printed piezoelectric sensors on composite panels. It explains the critical post-print polarization process that uses heat and applied voltage to align the unoriented crystals.
#PrintedPiezoelectrics, #PiezoelectricPolarization, #StructuralHealthMonitoring, #CompositeIntegration, #PrintedElectronics, #AerospaceComposites
00:05:36.055 - 00:06:14.245
Can you sinter metallic sensor inks on heat-sensitive composites without damaging the underlying substrate?
How can manufacturers overcome the thermal bottlenecks of conventional sintering to achieve high-throughput metallization on temperature-sensitive substrates?
The transition from wet-printed liquid ink to a highly conductive, solid metallic trace represents a critical phase in printed electronics fabrication. Traditional thermal curing methods are often incompatible with low-cost, flexible polymer substrates due to prolonged exposure to elevated temperatures. To resolve this, advanced photonic processing utilizes high-intensity xenon flash lamps to deliver rapid, localized energy pulses that selectively sinter the printed features without damaging the underlying material.
This transient photonic sintering mechanism relies on the selective absorption of broad-spectrum light by the metallic nanoparticles within the ink. The rapid absorption of energy generates localized heat that instantaneously volatilizes organic binders, solvents, and ink additives. Concurrently, it drives the diffusion and coalescence of the metallic nanoparticles, establishing a highly coherent, conductive percolation network in a fraction of a second.
Integrating this flash-based photonic curing technique into production lines dramatically accelerates manufacturing throughput. By replacing slow batch-oven baking with millisecond-scale optical pulses, the process aligns seamlessly with high-speed, continuous roll-to-roll fabrication workflows. This rapid, selective thermal processing ensures both structural integrity and high electrical performance at commercial scale.
In this short video, you can learn:
* How xenon flash lamp systems enable ultra-fast, selective sintering of printed metallic structures.
* The mechanism of rapid additive evaporation and nanoparticle coalescence during photonic curing.
* Why localized optical processing prevents thermal damage to sensitive substrate materials.
📋 **Clip Abstract** The speaker explains the necessity of sintering printed metallic structures using a rapid xenon flash lamp process. This photonic method selectively sinters the particles and evaporates ink additives extremely quickly, enabling high-speed manufacturing.
🎤 Speaker: Ingo Wirth
🏢 Company: Fraunhofer IFAM
📅 Event: Printed Electronics Innovation Day 2024
📍 Location: TechBlick | Online Platform
🌐 Learn more at the next TechBlick event: https://www.techblick.com
#PhotonicSintering, #PrintedThermocouples, #XenonFlashSintering, #CopperNickelInks, #StructuralElectronics, #PrintedElectronics