More and more creators are integrating electronics into their 3D prints. This guide covers all the basics of working with conductive filament so you can start working with 3D printed electronics.
(Source: 3DFilaPrint.com; Tony’s Buzz Trace printed using Protopasta filament)
What is conductive filament?
Conductive filaments are typically PLA filaments with conductive properties (usually using graphene or graphitized carbon) that can transmit electricity. The amount and type of additive used controls the conductivity of the filament, making some filaments better for certain applications.
Although many makers are interested in integrating electronics into their 3D prints, particularly when it comes to complex costumes, conductive filaments are still somewhat uncommon. There are a few well-established filaments that are loved by curious 3D print makers delving into electronics-integrated prints. In this article, we cover the basics of conductive filaments, what you need to know to get started, and a few recommended filaments.
How does conductive filament work?
Nearly all conductive filaments that are currently available are manufactured using a mixture of carbon and standard 3D printing thermoplastic—PLA, ABS, TPU, or HIPS, with the latter two being specialized and less likely to be used for consumer applications. To make these thermoplastics conductive, they are mixed with graphitized carbon. For those who aren’t well-versed in chemistry or materials science, this just means that the carbon atoms are arranged in a crystalline lattice structure that facilitates the transfer of a free electron, which allows the final material to conduct electricity.
In addition to facilitating electron donation and conducting electricity, this lattice structure yields a stronger and more rigid final print than their normal thermoplastic counterparts. Graphene, which refers to a single layer of honeycomb-latticed carbon, is very thin, making it perfect for use in 3D printing materials.
Is conductive filament useful?
While the biggest benefits of conductive 3D printing materials are typically seen in industrial applications, an increasing number of consumers and hobbyists have seen the potential of being able to custom-design electrical parts—whether for home fixtures or specialized costumes.
Wearable electronic devices have seen the greatest developments from conductive filaments by far. Owing to their thermoplastic characteristics, such as layering and flexibility, these filaments can be used to seamlessly integrate electrical circuits into durable yet moveable materials.
Another great use for this technology is sensor design. Touch, or capacitive, sensors detect motion at proximity and can be used for articulation and electronic motion (think mousepads, game controller touch pads, and some computer mouse designs) as well as level sensors for machines and tools. Owing to the huge open-source communities surrounding 3D printing, designs for these types of sensors are accessible for those with limited electronics design knowledge, making it easy to integrate this technology into your daily life.
It might be obvious, but we’re very excited about the prospects of conductive filaments. However, they have quite a few limitations that should be noted.
It’s common for 3D printing enthusiasts to overstate that this technology will make some other technology obsolete. Although conductive filament has a wide variety of unique applications, it still cannot reach the conductive levels of many metals. In fact, owing to the structure of graphene-mixed thermoplastics, they conduct electricity necessarily slower, so we aren’t likely to be able to completely become self-sufficient for tool making or home building with our 3D printers just yet.
Because the structure of the filament is mixed, conductive filament is necessarily more brittle than full-thermoplastic filament. While final prints are still quite durable, it is important that the filament itself is used with care to avoid breakage before the print is complete.
Another problem associated with mixed filament types is that the hard structure of the graphene within the filament can cause wear-and-tear on your hot-end nozzle. Wider and abrasion-resistent nozzles are typically sufficient for avoiding this issue, but it’s important to keep in mind when doing considering printer maintenance with new materials.
The final consideration for working with conductive filaments is that they are fairly expensive compared to standard PLA and ABS filaments, with some brands reaching over three times the price of standard filament spools. This cost barrier can deter some beginners from working with conductive filaments or encourage cautious use with what they have. We recommend finding a couple test projects with ample information regarding troubleshooting and clear steps when first working with this material so you can get comfortable with this new filament without accidentally wasting it.
Printing with conductive filament: The basics
We’ve gone over what you need to know about conductive filament itself—now, let’s jump into what to keep in mind when printing.
Because various base materials are used to manufacture conductive filaments, the printing temperatures for each type varies. PLA-based conductive filament is likely to have a recommended printing temperature of 220 to 230 °C, while ABS-based conductive filament may have a recommended temperature of up to 260 °C.
While we have many guides encouraging you to fine-tune your settings with loads of test prints at various temperatures, working with conductive filament requires more caution. These materials are a bit more delicate than your average filament, so it’s best to stay firmly within the manufacturer’s recommended temperature settings.
Like conventional filaments, a heated bed can help limit warping when printing with conductive filament. We recommend sticking to the 50 °C mark if using a heated bed.
If you do not have a heated bed and are experiencing some adhesion problems, conductive filament will respond well to most adhesion fixes like painter’s tape, adhesion glue, or stick glue on the build plate.
Most PLA-based conductive filaments, which are the most common, can be printed at relatively high speeds. The carbon component of your filament will not significantly impact heating and cooling of the filament itself, so you should be fine working at whichever print speed yields the best setting for your final print. AMOLEN, a conductive filament manufacturer, recommends printing speeds between 30 and 70 mm/s.
Powering your prints
Conductive filament must be used with a power source like an external battery. While this filament is built to handle an electrical load, it is very important that you stay within the electrical stress limits of the filament as exceeding the limit can burn the plastic and release carcinogens. Electrical stress limits vary depending on the filament manufacturer, but conductive filament can typically handle a load of up to 60 V/100 mA.
Checking with the manufacturer is also helpful regarding electrical load as most filaments should only be used for relatively small projects, like smaller sensors, lights, or circuits that will not require significant power.
Obviously, this is a hobby 3D printing blog, not an electrochemistry forum. However, to give you a better idea of how to compare different conductive filament, it’s important to understand the basic measures by which they are tested: conductivity and resistivity.
Electrical resistivity, the inverse of conductivity, is useful for identifying the voltage level a specific material can handle. Resistance is a fixed value that denotes how well a material resists electrical flow. Resistivity is slightly different—it denotes how resistant a material is per a unit length at a cross-section, which is important when working with materials that we measure by length (like filament).
We will not get into the calculations here; generally, all you need to know unless you really want to understand the ins and outs of electrical conductivity is the lower the resistivity, the more conductive a filament is. For our filament comparison below, resistivity is noted by Ω⋅cm, which is the most common unit used by filament manufacturers.
Comparing common conductive filaments
As stated above, a lower resistivity value indicates better conductivity. Here’s a comparison to give you an idea of what this looks like in practice:
- Copper: 0.00000168 Ω⋅cm (highly conductive)
- Hard rubber: 1,000,000,000,000,000 Ω⋅cm (non-conductive)
Beyond resistivity, another factor that will influence your print conductivity is orientation. Material printed continuously along the XY-plane will have better conductivity than that layered in the Z direction owing to their better contact. Orienting a part for optimal conductivity is an important factor to consider when working with electronics in your prints.
Protopasta recently released a conductive PLA filament as the result of a Kickstarter crowdsourced campaign.
Their conductive PLA has a resistivity of 30 Ω⋅cm along X- and Y-axes and 115 Ω⋅cm along the Z-axis. We chose this filament owing to its high customer ratings—many users report that it is generally as easy to use as conventional PLA. Though it is more expensive than your average filament, it is not as pricey as comparably performing conductive filaments, making it a good starting point for those just getting into conductive prints.
- Price/kg: $100
- Size: 1.75 and 2.85 mm
- Color: Black
- Resistivity: 15 Ω⋅cm
- Resistivity by axis: 30 Ω⋅cm (X- and Y-axes) and 115 Ω⋅cm (Z-axis)
- Nozzle temperature: 215–230 °C
- Bed temperature: 50 °C
Black Magic 3D
Black Magic 3D stocks a conductive PLA known as conductive graphene PLA. Its excellent electromagnetic properties and radio-frequency shielding ability makes it a great option for people who know exactly what they want out of a conductive filament, but it hikes the price up to $100 per 100 grams.
This filament has a resistivity of 0.6 Ω⋅cm with great mechanical strength surpassing that of conventional ABS and PLA. If you choose to use this filament, a nozzle diameter larger than 0.5 mm and layer thickness of 0.1–0.2 mm are recommended.
- Price/kg: $1,000
- Size: 1.75 mm
- Color: Black
- Resistivity: 0.6 Ω⋅cm
- Resistivity by axis: Unknown
- Nozzle temperature: 195–200 °C
- Bed temperature: 50–55 °C
Multi3D specializes in producing conductive materials, providing both conductive filaments and conductive filament pellets. While Multi3D’s Electrifi conductive filament is not PLA-based, it offers similar properties.
This filament is definitely expensive, but you get what you pay for with an outstanding resistivity of just 0.006 Ω⋅cm. It can also be printed with very low temperatures 130–160 °C, according to the manufacturer.
- Price/kg: $2,000
- Size: 1.75 and 2.85 mm
- Color: Bronze
- Resistivity: 0.006 Ω⋅cm
- Resistivity by axis: Unknown
- Nozzle temperature: 130–160 °C
- Bed temperature: Unknown
3dk.berlin manufactures a conductive PLA, known as 3dkonductive. This filament has electromagnetic shielding properties and is anti-static, making it suitable for more applications than a base conductive filament.
This filament boasts the ability to print well at speeds of up to 90 mm/s, which is excellent for a functional filament.
- Price/kg: $113
- Size: 1.75 2.85 mm
- Color: Black
- Resistivity: 24 Ω⋅cm
- Resistivity by axis: 24 Ω⋅cm (X- and Y-axes) and 53 Ω⋅cm (Z-axis)
- Nozzle temperature: 200–230 °C
- Bed temperature: Up to 70 °C
By now, you should be familiar with all the basics of conductive filament. Whether you want to build a lamp with an integrated capacitive sensor for your workstation or add some lights to your next cosplay build, getting familiar with this novel and unique filament is definitely worth it.