Printing electricity: everything you need to know about conductive filaments for 3D printing

When someone enters the world of conductive filaments, the first thing they discover is that the label “conductive” hides very different realities. Some materials merely dissipate static electricity, while others heat up, carry current, and act as circuit traces. The difference between them is not subtle: it is a matter of orders of magnitude. Understanding that difference is the key to avoiding unpleasant surprises.

In this post, we will go back to basics and explain what electrical conductivity is, how it is achieved in a plastic, which applications require each level of conductivity and, finally, we will analyse five very different filaments: Multi3D Electrifi, 3DXSTAT ESD PLA by 3DXTech, Filaflex Conductive by Recreus, Fili by AIMPLAS and Conductive PLA by Spectrum.

What exactly is conductivity?

Electrical conductivity (represented by the Greek letter σ, sigma) measures how well a material allows electric current to flow through it. Its unit is the Siemens per metre (S/m). The higher the value, the more easily electricity flows.

To give an idea of the scale:

As you can see, between pure copper and a low-end conductive PLA there is a difference of almost ten million times. And even among conductive filaments on the market there are differences of thousands of times. It is not a minor detail.

How is a plastic made conductive?

PLA, PETG and TPU are, in their pure state, perfect electrical insulators. In order for them to conduct electricity, conductive particles must be dispersed throughout the material. The idea is that these particles touch one another, forming a network of pathways through which current can move.

This has a name: electrical percolation. And it has a fascinating characteristic: it does not happen gradually. Up to a certain filler percentage, the material conducts almost nothing. As soon as that threshold is crossed (the electrical percolation threshold) and the particles start touching, conductivity can increase a thousandfold instantly. Beyond that point, adding more filler still improves conduction, but with diminishing returns.

The type of filler used determines how far conductivity can go:

• Carbon black. The cheapest and most widespread option. Spherical carbon particles obtained from the combustion of hydrocarbons. It provides moderate conductivity and is responsible for the black colour of most affordable conductive filaments. The percolation threshold requires quite a high filler content (around 15–20% by weight).
• Carbon nanotubes (CNTs). Nanometre-scale graphene cylinders whose length is much greater than their diameter. Thanks to this elongated geometry, they “touch” one another at much lower filler concentrations (just 1–5% by weight is enough), and can provide somewhat higher conductivity than carbon black. They are more expensive and harder to disperse evenly.
• Graphene. Sheets of carbon one atom thick arranged in a hexagonal lattice. Extremely high intrinsic conductivity and a very low percolation threshold. The problem is that “pure” graphene is difficult to process, and commercial filaments generally use reduced graphene oxide (rGO), whose actual conductivity ends up being far more modest.
• Metal particles (copper, silver, nickel). This is where the real leap occurs. Once metal becomes part of the network, conductivity can be one hundred or one thousand times greater than with any carbon filler. This is the technology behind the Electrifi by Multi3D, the only FFF filament on the market that uses copper. The trade-off is that it is more abrasive and requires hardened steel nozzles.

Not all “conductive” filaments are suitable for the same applications

This is the central point that causes the most confusion. Depending on its level of conductivity, a filament is suitable for completely different purposes:

Level 1 – Anti-static / ESD (those that barely conduct)

These materials do not carry current in any useful way, but they do prevent static electricity from building up. When you touch a part made from this material, charges dissipate slowly instead of accumulating until they discharge suddenly.

What is this useful for? Protecting sensitive electronic components: integrated circuit trays, microchip storage boxes, environments where a spark could cause a fire. Also for rollers and machine guides where static causes adhesion or dust-attraction problems.

What cannot be done with them: lighting an LED, generating heat, or using the material as a circuit trace.

Level 2 – Sensors / signalling (those that conduct “a little”)

Here the material does conduct current, but with such high resistance that it only works in very low-current applications. The most intuitive way to understand it: they are suitable for anything that works through a 1 kΩ resistor.

That includes Arduino digital inputs (detecting whether there is contact or not), touch sensors, low-resolution keyboards, trackpads, or pressure sensors where what changes is the electrical resistance when the part is compressed. It is not possible to power a bulb directly or run a motor.

What can be done: prototyping touch interfaces, piezoresistive sensors, educational electronics projects, wearables where the traces only need to signal rather than carry power.

Level 3 – Functional conductor (those that genuinely conduct)

In this range, the part can carry real current, generate controlled heat through the Joule effect, serve as a reliable grounding path or act as electromagnetic shielding. This is a radically different category from the previous ones and, in the current FFF market, it is occupied solely by Electrifi from Multi3D.

What can be done: printed heaters with customised geometry, power distribution traces for prototypes, enclosures with integrated grounding, EMI shielding, low-voltage interconnections without soldering.

Five filaments, five very different profiles

Multi3D Electrifi — The one that genuinely conducts

The Electrifi is an anomaly in the conductive filament market, in the best possible sense. Its copper filler gives it a conductivity of 10,000 to 100,000 S/m, between three and five orders of magnitude higher than any carbon-based filament. With it, you can genuinely heat, conduct and ground.

It prints at an unusually low temperature for this kind of material (140–200 °C), requires slow speeds (10–20 mm/s), 100% infill and preferably 0.6 mm hardened steel nozzles. The colour is bronze/copper, which gives a visual clue as to what is inside.

Its ideal positioning: R&D teams, prototyping engineers and manufacturers who need to integrate genuine electrical functionality into printed parts without resorting to metalworking processes. It is not intended to replace copper in high-power applications, but rather to fill the gap between “it does not conduct at all” and “you need to machine metal”.

In summary: the only FFF filament with true functional conductivity. Essential if the application requires current, heat or grounding.

3DXSTAT ESD PLA (3DXTech) — The electrostatic protection specialist

While the rest of the filaments in this selection aim to “conduct as much as possible”, the 3DXSTAT ESD PLA by the American company 3DXTech does exactly the opposite: it is designed to conduct just enough, and in a highly controlled way. Its declared target is a surface resistivity of 10⁷ to 10⁹ Ω/□, the range defined by industry standards as ESD-safe.

Why is that very specific range so important? Because ESD protection does not work with either too much insulation (charges build up) or too much conductivity (a sudden discharge can still damage the component). The 10⁷–10⁹ Ω/□ range is the window in which charges dissipate slowly and in a controlled way, without risk to sensitive components. 3DXSTAT targets that value with a consistency and repeatability that sets it apart from generic conductive materials.

Its base material is NatureWorks PLA — one of the highest-quality PLAs on the market — loaded with multi-wall carbon nanotubes (MWCNTs). CNTs allow this percolation threshold to be reached with a small amount of filler, resulting in a cleaner part with low particle contamination and minimal outgassing: critical aspects in semiconductor or cleanroom environments where ionic contamination can ruin an entire process.

It prints between 210 and 220 °C, without requiring a heated bed or enclosed chamber. A hardened nozzle is not necessary — the CNT concentration here is low enough not to cause significant wear — although a 0.5 mm nozzle or larger is recommended to avoid clogging. Printing temperature has a direct and measurable effect on the final conductivity: printing at the upper end of the range (220 °C) produces lower and more consistent resistivity values.

Its target applications are very specific and high-value: hard drive components, silicon wafer handling trays, jigs and connectors for semiconductor production lines, robotic end-of-arm tooling, and any industrial environment where ESD is a genuine and documented risk.

In summary: this is not a “conductive” filament in the usual sense, but rather a precision ESD engineering material. When surface resistivity matters as much as the dimensions of the part, 3DXSTAT is the right tool.

Filaflex Conductive (Recreus) — Flexibility and conductivity combined

Recreus, the Spanish company that has long been a benchmark in flexible filaments, applied its TPU expertise to the conductive world. The result is a filament with Shore 92A hardness (similar to a running shoe sole) that also conducts electricity with a resistivity of ~3.9 Ω·cm (~25 S/m).

What makes it unique is not just its conductivity, but that the part retains that conductivity when deformed and recovers it afterwards. A pressure sensor printed with Filaflex Conductive works when compressed, deforms, and when released returns to its original state with the same electrical properties. This opens up applications that no other material on the market can cover: textile electronics, ECG patches, conformable interfaces, EMI shielding that must adapt to curved geometries.

It requires high temperatures (240–255 °C) and slow speeds (20–25 mm/s), and the part-cooling fan should be disabled to prevent heat dissipating before the layers bond properly. It does not require a hardened nozzle, which simplifies the process.

In summary: the only option when you need a part to bend, compress or stretch while remaining conductive. A benchmark for wearables and flexible electronics.

Fili (AIMPLAS × Filament2Print) — The laboratory filament

Fili is the result of a collaboration between AIMPLAS — the Spanish Plastics Technology Centre with more than 30 years of experience — and Filament2Print.

What stands out most about Fili is not its conductivity (similar to other TPU materials on the market), but its exceptional surface finish. Printed parts display a homogeneous surface with scratch-resistant behaviour that is unusual in carbon-loaded materials, which are typically more porous and rough. This makes it interesting for applications where conductive functionality and final-part aesthetics need to coexist.

In summary: a conductive TPU developed in Spain with a premium finish. A good balance between flexibility, conductivity and final-part appearance.

Spectrum Conductive PLA — Carbon nanotube technology

Spectrum Filaments relies on a technology different from traditional carbon black: carbon nanotubes (CNTs). CNTs are nanometre-scale graphene cylinders whose elongated geometry allows them to form conductive networks with lower filler concentrations and, in theory, greater efficiency.

The result in terms of surface resistivity is impressive: ~10 Ω/□, making it highly interesting for ESD applications. However, its volumetric resistivity (97–120 Ω·m depending on printing temperature) is higher than that of other filaments on the market, which means that for bulk conduction — what you would need for a genuine circuit trace — it is not the strongest performer.

That said, it retains all the advantages of PLA: it does not warp, prints without an enclosed chamber, offers excellent dimensional stability and a carefully refined matte finish. One interesting detail: printing at 230 °C instead of 210 °C reduces volumetric resistivity by 20%, because the additional heat improves the dispersion of nanotubes within the structure.

In summary: Conductive PLA is the natural candidate for educational or laboratory environments seeking reliable ESD properties and easy printing. Carbon nanotubes improve surface behaviour compared to traditional carbon black.

How to maximise the conductivity of any filament

Choosing the right material is only half the job. Printing parameters can make differences of up to an order of magnitude in the final conductivity of the part. These are the most important:

• Extrusion temperature: the hotter, the better. Heat improves polymer flow and allows conductive particles to move closer together. In Spectrum PLA, increasing from 210 to 230 °C reduces resistivity by 20%. For Filaflex, it is recommended to use the upper end of the range (240–255 °C).
• 100% infill, always. Partial infill introduces discontinuities into the conductive network. For any section that needs to conduct, infill must be 100%. There are no shortcuts here.
• Slow speed, between 10 and 25 mm/s. At high speeds, the material cools before the particles establish contact with one another. Speed is probably the parameter that surprises people most: it seems strange that printing more slowly improves electrical properties, but physically it makes perfect sense.
• Design traces with electricity in mind. The resistance of a conductor follows this logic: longer → more resistance; wider or thicker → less resistance. Designing wide traces, avoiding bottlenecks and minimising path length is just as important as the material itself.
• The Z axis is the most resistive. Stacked layers conduct worse vertically than in the XY plane. If critical traces can be oriented in the print plane, much better.
• Reduce or eliminate the fan with TPU materials. Forced cooling can interrupt layer fusion before particles establish contact. For Filaflex Conductive, the manufacturer recommends disabling the fan completely.
• Steel or ruby nozzles for abrasive materials. Electrifi (copper) and Spectrum (CNTs) wear down brass nozzles. With a worn brass nozzle, the output diameter changes and conductivity becomes unpredictable. 3DXSTAT ESD PLA and Filaflex Conductive are exceptions: they do not require hardened nozzles.

Which one should you choose? A quick guide

And if you still have doubts, here is the key question that simplifies everything: do you need the part to carry real current, or simply to dissipate it in a controlled way? If the answer is “carry current”, Electrifi is currently the only real option on the FFF market. If the answer is “protect components from static”, the important distinction is whether the environment is a precision industrial setting (3DXSTAT) or educational/laboratory use (Spectrum). And if you need the part to bend, then Filaflex or Fili are the options to choose.