Julie Ferrigno | Henkel: How do you accurately calculate printed trace resistance and convert sheet resistance to bulk volume resistivity?

How can manufacturers achieve highly conductive, complex 3D conformal circuitry without relying on traditional subtractive plating methods?

Pad printing offers a precise, additive alternative for depositing functional electronic materials onto non-planar substrates. The process utilizes an ink cup positioned over an etched cliché plate to transfer formulated functional inks via a silicone pad directly onto 2D or 3D surfaces. By executing multiple print cycles sequentially, manufacturers can precisely control deposition thickness, optimizing the cross-sectional area of the trace to achieve lower electrical resistance.

To meet the diverse mechanical and electrical demands of integrated antennas and 3D circuitry, material systems are categorized by their functional roles. Highly conductive surface inks serve as the primary signal-carrying layer, while specialized contact inks sacrifice some conductivity to provide superior mechanical robustness and abrasion resistance. Complementing these pad-printable materials, low-viscosity, void-free via fillers are dispensed via syringes to establish reliable vertical electrical connections between the conductive layers.

Selecting the optimal ink formulation requires balancing electrical performance, substrate adhesion, and production logistics. High-conductivity surface inks like ECI 1203 and 1216 offer excellent conductivity and moderate abrasion resistance, but require specific cold-storage profiles—refrigeration versus freezing—that impact manufacturing workflows. Conversely, highly resistive contact inks like ECI 1227 prioritize extreme durability, surviving thousands of abrasion cycles while ensuring robust adhesion to challenging glass and polymer substrates.

In this short video, you can learn:
* The mechanics of transferring functional electronic inks from 2D clichés to 3D surfaces using silicone pads.
* The functional distinctions between high-conductivity surface inks, abrasion-resistant contact inks, and fluid via fillers.
* How storage requirements and substrate adhesion profiles influence the selection of specific conductive ink grades.

📋 **Clip Abstract**
The speaker explains the mechanics of pad printing conductive inks from a 2D cliché to a 3D surface, detailing how multiple passes can build thickness to lower resistance. She also categorizes their functional ink portfolio into surface inks, contact inks, and via fillers, comparing the conductivity, abrasion resistance, storage requirements, and substrate adhesion of specific product grades.

🎤 Speaker: Julie Ferrigno
🏢 Company: Henkel
📅 Event: Future of Electronics RESHAPED USA 2026
📍 Location: Computer History Museum, Mountain View, California, USA

🌐 Learn more at the next TechBlick event: https://www.techblick.com

How does pad printing stack layers "wet-on-wet" without inducing severe dimensional distortion?

Building trace thickness is a common challenge in printed electronics, often requiring multiple passes to achieve low resistance. In pad printing, applying subsequent layers "wet-on-wet" introduces the risk of ink spreading and smearing under physical pad pressure. Resolving this paradox relies on understanding the precise phase-change dynamics of the ink during the momentary transfer cycle.

Unlike screen printing where the deposited ink remains highly fluid, pad-printed ink undergoes rapid solvent evaporation. By the time the silicone pad transfers the ink from the cliché to the substrate, the ink is already in a "semi-dry" state, forming a stable skin. This immediate physical stability prevents lateral spreading when the pad compresses the next layer.

Once the multi-pass, semi-dry wet-on-wet build is complete, the final material properties are locked in through a prolonged thermal step. Typically, a two-hour bake in an industrial box oven is required to fully drive off the remaining deep solvents. This ensures complete densification and optimal conductivity of the thick-film structure.

In this short video, you can learn:
* The rheological difference between fluid screen-printed films and semi-dry pad-printed transfers.
* Why solvent evaporation during the silicone pad transfer prevents trace deformation during multi-pass prints.
* The critical role of long-term oven curing in achieving final electrical properties.

📋 **Clip Abstract** This technical Q&A session addresses the mechanics of multi-pass pad printing. Julie Ferrigno details how the semi-dry state of the ink during transfer allows for wet-on-wet layering without lateral deformation, followed by thermal curing to secure final trace conductivity.

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Is pure silver still the gold standard for high-frequency printed electronic pathways?

Printing high-performance, large-scale antennas requires balancing electrical conductivity, ink viscosity, and overall manufacturing cost. By utilizing extremely low-resistance silver inks, designers can achieve superior current densities and transmission efficiency with minimal material laydown. This approach dramatically optimizes cost and sustainability, saving up to 50% of the total manufacturing and labor cost compared to traditional structural materials.

The technical trade-offs among Henkel's flagship silver inks highlight the importance of viscosity engineering. ECI 1010 offers exceptional versatility for screen, flexographic, and rotogravure printing. Meanwhile, ECI 1011 delivers an ultra-low sheet resistance of just 3 milliohms per square per mil, accommodating high-speed processing and even aerosol jetting.

When trace height is the limiting factor for track resistance, highly viscous options like ECI 1017 become essential. It can achieve a dry film thickness of 10 microns in a single pass. This single-step deposition minimizes the need for multiple printing runs, optimizing production cycle times while securing robust electrical pathways.

In this short video, you can learn:
* How high-conductivity inks reduce material usage while boosting transmission efficiency.
* The key differences in sheet resistance and processing versatility between ECI 1010 and ECI 1011.
* Leveraging high-viscosity inks to achieve a 10-micron trace thickness in a single print pass.

📋 **Clip Abstract** This clip explores the performance characteristics of high-conductivity silver inks engineered for large-scale printed antennas. Julie Ferrigno explains how matching ink viscosity and sheet resistance to the deposition process can reduce material costs by up to 50% while maintaining exceptional electrical properties.

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