Endless Exploration EX5 (November 2024) Dissipative Filaments for ESD Applications
The title is not so witty, so let's get down to the nitty gritty. This month we chose electrical conductivity as our topic. We formulated three new static dissipative versions of PLA, Carbon Fiber PLA, and PETG for use around sensitive electronics with electronics fabrication and repair in mind. More about that below, but first let's revisit our original Electrically Conductive PLA.
Protopasta introduced Electrically Conductive PLA filament in 2015 on Kickstarter. Electrically Conductive PLA is still a leading choice for customers seeking an easy printing, highly conductive 3D printing filament to 3D print wearable electronics, capacitive touch sensors, and circuits with LEDs. It's helpful to think of Conductive PLA more like a resistor in circuit than wire.
Our customers are very creative with this material, find it quite useful, and use it in more ways than we are aware of. While Electrically Conductive PLA can be used to dissipate static electricity, it was designed to maximize conductivity to higher than dissipative levels. Below is a table with typical resistances for Protopasta Conductive and Dissipative filaments.
The above measurements are typical values from manufacturing when measuring a 10 cm length of 1.75 mm diameter filament. Because of the different resistance magnitudes, we use different meters to measure the resistance of Conductive and Dissipative materials. Below is a look at what we use to quality control these materials to make sure they are within the above ranges.
While measuring filament is practical for validation in manufacturing, we created printed artifacts for resistivity values of these materials measured and calculated with more industry typical methods. For Conductive PLA, we printed bars to calculate volume resistivity using the below items.
Example results for Conductive PLA are as follows. Your results will vary as these numbers are based on our specific printer, parameters, material batch, test setup, and environmental conditions. Results will also change with geometry. More details regarding our conditions to follow in technical data sheets.
Note that for Conductive PLA, volume resistivity is the appropriate measure and a standard DMM is the appropriate measurement device. Volume resistivity is calculated from the printed artifact form and measured resistance. For Dissipative PLA, the below items are appropriate.
Dissipative materials are judged by their surface resistance. Surface resistance of a flat sheet is measured with a Concentric Ring Probe and meter designed for higher resistance measurements. We printed sheets in various orientations, at multiple temperatures, and for all 3 Dissipative filaments. Values are 10^4-10^6 range with examples and more detail in the technical data sheets. Sample below.
There are differences in X-Y vs Z, based on temperature, and between materials. The differences, however, should not affect the suitability of these materials for the application of static dissipation. With all materials being suitable for ESD, the end user can then select based on a preference for PLA vs. PETG, flexible vs. rigid, aesthetic reasons, etc.
Dissipative PLA and PETG versions are lower modulus than the Carbon Fiber PLA version and have more give in bending. Dissipative Carbon Fiber PLA has the same aesthetic, rigidity, and form benefits as Carbon Fiber PLA.
Which filament is your favorite? What will you print? Show us on social (links below).
Not an Endless Exploration Subscriber? Subscribe by December 31st for our next delivery in January (topic: metal) and/or purchase static dissipative filaments individually in December.
Take care and enjoy the pasta,
Alex and the Protopasta Team
Some additional processing notes: Prepare for more wear and/or use a wear resistant components when printing Carbon Fiber. Conductive filaments are highly loaded with carbon black and may require more purging than other black filaments. These materials release well from textured PEI, but may stick too well to other build plate materials. Use caution and Magigoo or glue stick to release.
For more processing details, see technical data sheets on our Material Data page.
