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Preventing Electrostatic Discharge (ESD) Events
Preventing electrostatic discharge (ESD) events that can damage sensitive electronic components during manufacturing is primarily accomplished through the use of tools, clothes, covers, trays, and grippers made of ESD-safe materials. This article discusses the scientific principles behind what gives a 3D printer filament ESD-safe properties, and why Nexa3D’s Essentium materials are the best choice for your ESD-safe applications.
Creating Surface Resistance with Carbon
3D printer ESD-safe filaments for electrostatic discharge applications typically are infused with carbon or graphite additives. Carbon particles provide electrical resistance properties when jigs and fixtures come in contact with electronic components; any buildup of static electricity flows harmlessly into the ground, not into the part. The amount of carbon filler added to the polymer determines the level of surface resistance from electrically conducting to dissipative to insulating.
This property is measured in ohms. Materials with a surface resistance rating of 1 x 104 ohms to 1 x 1011 ohms are dissipative and generally considered safe for use in electronics manufacturing applications.
The polymer itself can be flexible for printing PCB boots, or rigid for printing ESD-safe spudgers, tweezers, and screwdrivers. It all depends upon the durometer or stiffness of the base material to which the carbon is added.
The Carbon Compromise: Not All Carbon is Created Equal
The trouble with many ESD-safe filaments is that a relatively high percentage of carbon, usually between 15% and 25%, is required to achieve the desired electrostatic dissipative effect. The addition of that amount of conductive filler can substantially alter the characteristics of the polymer, making it chalky, brittle, or impacting chemical or temperature resistance properties, for example.
Further, materials with high carbon content suffer from severe sloughing issues and are prone to marking or marring the parts they are designed to protect.
To counteract this, filament makers will add plasticizers to restore some ductility to the composite. This only further compromises mechanical properties of the material and can result in lower impact resistance or poor elongation at break when force is applied during product assembly.
The Nexa3D’s Essentium 3D Printer ESD-Safe Filament Solution: Less is More
To address the needs of non-marking and non-marring ESD-safe electronics manufacturing applications, Nexa3D’s Essentium offers an entire portfolio of ESD-safe filaments.
These best-in-class materials are easy to print and finish and are available in multiple spool sizes and diameters.
The Nexa3D’s Essentium Z Collection of ESD-safe materials are engineered to provide the necessary surface resistance properties without compromising the performance of the filament. Nexa3D’s Essentium Z Collection filaments use much less carbon, as little as 0.01% in the overall material.
The key is a combination of multilayer filament and dispersed carbon nanotube technology.
Carbon Nanotubes: The Key to Affordable ESD-Safe 3D Printing
Carbon nanotubes are a cutting-edge class of nanomaterials that solve many of the challenges associated with other conductive fillers. Carbon nanotubes can create an electrically conductive network in a polymer matrix at very low loading levels because of their incredibly high aspect ratio of length to diameter.
Extremely versatile conductors of electricity, carbon nanotubes allow for precise manipulation of conductivity. Engineers can select the desired material properties ranging from highly electrically conductive to electrically insulating by exactly tuning the loading level and percolation behavior of nanotubes in the polymer. Carbon nanotubes also tend to reinforce the polymer matrix, making it slightly stronger and more wear-resistant.
Nexa3D’s Essentium Z Collection Takes Carbon Nanotube Technology to Next Level
Nexa3D’s Essentium currently offers a family of five ESD-safe materials in our Z Collection, each optimized for different electronics manufacturing applications from flexible to rigid. We use only high-purity carbon nanotubes combined with our proprietary extrusion process to extrude a multilayer 3D printer filament that concentrates the nanotubes onto the surface of the filament rather than throughout the entire volume of the material.
With Nexa3D’s Essentium proprietary compounding technology, carbon nanotubes are completely bound to the polymer matrix and evenly disbursed to avoid conglomeration or clumping, meaning Nexa3D’s Essentium ESD-safe filaments have superior non-marking and non-marring qualities and will not rub off onto sensitive devices or cosmetic surfaces.
As a result, Nexa3D’s Essentium Z Collection filaments achieve desired results without compromise. Because the core of the filament is the base polymer, all of the desired mechanical and thermal properties of the material are retained. The conductive outer layer of the filament is on the order of a few microns thick (fractions of the width of a human hair) and does not appreciably alter the physical properties, it simply encases the filament in an ESD-safe layer.
This also impacts cost. Most high-performance ESD-safe filaments are expensive. With Nexa3D’s Essentium Z Collection, only a small fraction of the filament mass contains carbon nanotubes, minimizing cost. Finally, Nexa3D’s Essentium open ecosystem approach means these materials can be used with Nexa3D’s Essentium High Speed Extrusion (HSE™) 3D Printers or any other open source 3D printer.
Nexa3D’s Essentium Z Collection of industrial-grade filaments offers superior performance across a wide range of electronics manufacturing applications that require protection from ESD events.
