PCB Renewal: Iterative Reuse of PCB Substrates for Sustainable Electronic Making

TL;DR

PCB Renewal presents a substrate-preserving approach to electronic prototyping by locally erasing and reconfiguring copper traces with conductive epoxy, enabling multiple design iterations on a single FR-4 board. The authors detail a four-step fabrication pipeline, material criteria for the epoxy, a KiCad-based plugin for design comparison and fabrication profiling, and extensive electrical/mechanical testing including trace conductivity, solder joints, and renewal durability up to seven iterations. A delta-LCA-like sustainability model quantifies material, time, and energy trade-offs against fabricating new boards, revealing substantial waste reductions in representative scenarios. Demonstrations across in-house and outsourced PCBs illustrate practical gains in material savings, energy use, and cost, while discussions acknowledge limitations and outline automation and broader adoption paths with potential industrial-scale impact.

Abstract

PCB (printed circuit board) substrates are often single-use, leading to material waste in electronics making. We introduce PCB Renewal, a novel technique that "erases" and "reconfigures" PCB traces by selectively depositing conductive epoxy onto outdated areas, transforming isolated paths into conductive planes that support new traces. We present the PCB Renewal workflow, evaluate its electrical performance and mechanical durability, and model its sustainability impact, including material usage, cost, energy consumption, and time savings. We develop a software plug-in that guides epoxy deposition, generates updated PCB profiles, and calculates resource usage. To demonstrate PCB Renewal's effectiveness and versatility, we repurpose a single PCB across four design iterations spanning three projects: a camera roller, a WiFi radio, and an ESPboy game console. We also show how an outsourced double-layer PCB can be reconfigured, transforming it from an LED watch to an interactive cat toy. The paper concludes with limitations and future directions.

Figures (11)

• Figure 1: PCB Renewal principle illustration: a) initial PCB engraved, b) selectively depositing conductive filler into isolation grooves, c) re-engraving new circuit trace.
• Figure 2: Illustration of conductive epoxy behavior at different viscosities: a) excessively high viscosity, b) excessively low viscosity.
• Figure 3: Fabrication workflow: a) old board, b) desoldering, c) manual epoxy deposition with a stencil,, d) epoxy curing, e) engraving new traces, f) new functional PCB with a modified trace.
• Figure 4: Fabrication resolution: trace engraving was attempted on a conductive epoxy pour at various trace widths.
• Figure 5: Material interface experiment: a) hybrid material traces (20 mil wide), b) illustration of measurement points.