Hendrik Mohrmann | CONTAG AG: Why Does Bulk Copper Solve the Hysteresis and Resistivity Problems of Conductive Inks?
00:03:51 - 00:05:05
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Why Does Bulk Copper Solve the Hysteresis and Resistivity Problems of Conductive Inks?
In stretchable printed electronics, conductive inks exhibit electrical hysteresis, meaning their electrical resistance shifts dynamically under mechanical strain and does not recover instantly. This variability poses a major hurdle for precision analog signaling and power transmission in wearable devices.
Bulk copper on polyurethane offers a direct material-level solution, yielding orders of magnitude lower electrical resistivity and a stable resistance profile during stretching. Experimental data shows that engineered copper traces can withstand up to 10,000 stretch cycles at over 10% strain before encountering fatigue-induced resistance changes.
While conductive inks still offer superior ultra-high strain limits, combining bulk copper with stretchable inks yields highly optimized hybrid systems. This combination leverages the high electrical performance of copper alongside the extreme mechanical compliance of printed materials.
In this short video, you can learn:
* The core differences in electrical resistivity and hysteresis between bulk copper and conductive inks.
* How fatigue testing demonstrates copper trace survivability over 10,000 cycles at 10% strain.
* The design strategy of combining copper and ink-based technologies to build high-performance stretchable systems.
๐ **Clip Abstract** This clip compares the electrical performance of bulk copper against conductive inks, focusing on resistivity, fatigue life, and strain-induced hysteresis. It highlights copper's ability to survive 10,000 stretch cycles at over 10% strain while maintaining highly stable resistance.
#BulkCopper, #ElectricalHysteresis, #ConductiveInks, #CopperOnPolyurethane, #StretchableElectronics, #WearableDevices
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00:01:28 - 00:02:47
Can Bulk Copper Foil Outperform Printed Inks in Highly Stretchable Multi-Layer Electronics?
Can Bulk Copper Foil Outperform Printed Inks in Highly Stretchable Multi-Layer Electronics?
Traditional stretchable electronics often rely on screen-printed or inkjet-printed conductive silver inks, which suffer from high resistivity and mechanical degradation. By laminating and etching a pure, bulk copper foil directly onto thermoplastic polyurethane (TPU), it is possible to achieve up to 30% stretchability with high-density features down to 50 microns.
This approach integrates seamlessly with standard multi-layer PCB processes, allowing the fabrication of rigid-flex-stretch systems without the need for unreliable connectors, plugs, or cables. The resulting mechatronic assemblies can embed sensors via laser blind vias and handle anisotropic conductive sheets.
Furthermore, because these systems are built with bulk copper, they can be assembled using standard surface-mount technology (SMT) and solder reflow processes. This eliminates the need for specialized conductive adhesives and ensures robust component attachment on flexible substrates.
In this short video, you can learn:
* How bulk copper on TPU achieves 30% stretchability with 50-micron line/space resolution.
* The integration of multi-layer PCBs and embedded sensors using laser blind microvias.
* Why bulk copper eliminates the need for connectors and enables standard SMT soldering.
๐ **Clip Abstract** This clip explains how bulk copper foil can be laminated and etched onto TPU using standard PCB manufacturing to create robust, stretchable multi-layer circuits. The method enables 30% stretchability and direct SMT assembly without specialized conductive glues or connectors.
#BulkCopperFoil, #StretchableElectronics, #RigidFlexStretch, #LaserBlindVias, #FlexibleHybridElectronics, #WearableTechnology
00:08:54 - 00:10:48
How Can 3D-Printed Resins Replace Injection Molding for Laser Direct Structured Mechatronics?
How Can 3D-Printed Resins Replace Injection Molding for Laser Direct Structured Mechatronics?
Mechatronic Interconnected Devices (3D-MIDs) traditionally require expensive, long-lead-time injection-molded thermoplastics like PEEK or LCP. To accelerate the prototyping cycle, SLA/DLP 3D printing can be utilized with high-temperature, UV-curable photopolymer resins loaded with specialized metal-oxide additives.
By applying Laser Direct Structuring (LDS) to the printed parts, a laser selectively reduces the embedded metal oxides, creating microscopic metal seed paths. These activated areas then act as catalysts for subsequent electroless copper plating to form highly conductive 3D circuit traces.
The ablation of the polymer during the laser activation process introduces micro-roughness, which significantly enhances mechanical interlocking. This yields excellent copper peel strength values that comply with rigid IPC standards, enabling robust 3D circuitry on thermally stable photopolymers.
In this short video, you can learn:
* How to use UV-setting stereolithographic resins with metal-oxide additives for 3D-MID fabrication.
* The mechanism of Laser Direct Structuring (LDS) for selective chemical copper plating on 3D printed surfaces.
* Why laser-induced surface roughness is critical for achieving IPC-compliant trace peel strength.
๐ **Clip Abstract** This clip details a novel method for directly 3D printing Mechatronic Interconnected Devices (3D-MIDs) using photopolymer resins and Laser Direct Structuring (LDS). The technique enables rapid prototyping of thermally stable 3D circuits with IPC-compliant copper adhesion.
#LaserDirectStructuring, #3DMID, #ElectrolessCopperPlating, #PhotopolymerResins, #AdditiveElectronics, #3DPrintedElectronics