Electrostatic discharge (ESD) is a growing concern in additive manufacturing as electronic components become smaller and more critical for medical devices and precision parts. In this podcast, John Kawola, CEO of Boston Micro Fabrication (BMF), and Olga Ivanova, director of technology at Mechnano, discuss ESD materials and how they open doors for additive manufacturing. Scroll down to read a recap of the conversation.

What is electrostatic discharge (ESD) and what are the corresponding issues and hazards?

Olga Ivanova: Electrostatic discharge occurs due to the buildup and release of static electricity, which is caused by the transfer of electrons between materials. It is mainly triggered by friction, contact, or separation between different objects or surfaces. A prime example is when you reach for the doorknob and get a shock — that is a contact of two objects. Another good example is when you take off your hat in very dry, cold weather and your hair stands out because it’s statically charged — that is when the separation friction happens. While in this case, this might seem harmless, it can pose significant issues and hazards in various industries.

One of the main concerns is the potential damage to the electronic equipment. When ESD occurs near electronic devices, it can generate a high voltage surge that surpasses the tolerance levels, leading to permanent damage or system failure. It can also cause data loss of the computer systems or disrupt the functionality of medical devices.

Besides these electrical issues, or rather technical issues, ESD can also pose safety hazards to individuals, such as electric shock or fires in environments containing flammable materials or explosive materials, for example. Thus, understanding the causes and potential hazards of this electrostatic discharge is very crucial to effectively preventing the damage to equipment and ensuring the safety of the personnel and various work environments.

What are ESD-safe materials and how do they work?

Ivanova: ESD-safe materials are commonly classified into three distinct categories based on the properties and the way they transfer the charge: anti-static, conductive, or dissipative. Anti-static material possess either no charge or minimal initial charge, effectively preventing the transfer of electrical discharge to or from human contact. The best example of anti-static materials is the Bounce sheets for your laundry. Conductive materials are characterized by a low electrical resistance. They facilitate the easy movement of electrons across the surface or through the material itself. This enables the rapid dissipation of electric charges to the ground or another conductive material that comes into contact with the object.

Dissipative materials facilitate a controlled and very gradual flow of electric charges towards the ground compared to conductive materials, which dissipates charge very quickly. The ability to slow down the discharge process makes dissipative materials extremely well suited for ESD-prone environments, as they effectively reduce the energy output and prevent electrostatic discharge. By employing these different types of materials, depending on the situation or application, the risk of damage caused by static electricity can be significantly mitigated.

How does the new Formula1µ ESD resin influence additive manufacturing?

Ivanova: Mechnano focuses on the advancement of additive manufacturing materials using carbon nanotubes (CNTs), specifically. Due to their unique structure, CNTs possess exceptional characteristics, notably excellent tensile strength, electrical, and thermal conductivity. Despite having those impressive attributes, carbon nanotubes tend to aggregate into clumps during the manufacturing process. And in this clumped state, they struggle to effectively transfer their properties to the material they’re introduced to, resulting in a performance similar to that of carbon black.

Our technology focuses on addressing the natural tendency of carbon nanotubes to agglomerate by achieving a discrete state and subsequently modifying the sidewalls to prevent reagglomeration. That enables us to enhance performance of the base materials and unlock additional properties, such as conductivity. As a result, we expand the scope of applications for additive manufacturing materials. Currently, our primary focus is on ESD-safe materials, and one of our developments is the Formula1µ. This rigid ESD resin is compatible with BMF machines, which offer an excellent choice for manufacturing intricate ESD-safe components. And this marriage of the BMF hardware and Formula1µ serves as a quick and cost effective alternative to conventional labor-intensive and expensive machining of ESD-safe parts.

How does this new material open up more possibilities for BMF users?

John Kawola: BMF exists because our focus is on very high precision, high resolution performance, typically on smaller parts. Sometimes it’s bigger parts with very fine details, but in a lot of cases, it’s smaller parts. We find that our customers are grouped into four categories: electronics components, medical device components, optics and photonics, and life science and diagnostics. In a lot of these applications, the parts are being used either in the end component — such as an electrical device or medical device — as a fixture, or on the assembly line as these components are being produced.

In a number of these cases, ESD is an issue. So whether the buildup of static is creating a problem with the output from a medical device, or if it’s a safety issue, as Olga mentioned, these are all real-world problems typically addressed by making ESD parts, but by machining them. That’s labor intensive, it costs a lot of money, it takes a lot of time. If you’re on a production line and have ESD fixtures or ESD carriers and they break or wear out, you need a replacement immediately. So there is an incentive to have the ability to quickly create these components and quickly create a redundancy to keep your production line up.

One of the realities at BMF is that we’re serving a market where lots of customers are making very small parts. There are lots of trends out there for things getting smaller. Medical devices are getting smaller because people want less invasive surgeries. Electronics components are getting smaller and smaller every day. Optics and photonics are getting smaller. So, again, we exist because there’s this miniaturization trend happening across lots of industries.

But one of the challenges in making parts is as things get smaller, they get harder to make in that conventional way. They get harder to mold, machine, or stamp. We’re serving that need not only for development and engineering, but in some cases for production. So having an ESD material included in our lineup has been a nice addition because we have customers asking for it all the time.

What are the advantages of 3D printing instead of injection molding for these smaller parts?

Kawola: This applies for small parts and large parts, so it’s across the spectrum. The added urgency with small parts is that typically the molds you might use for injection molding are more difficult and more expensive to make. An injection mold for a macro part — maybe the size of your coffee cup or the computer mouse on your desk — is typically on the order of 10s of 1,000s of dollars to make that mold. But when you’re making something very, very small with a micron-level tolerance, that mold might be 10 times more expensive. That’s the difference with small parts.

On a broad level, why would you use 3D printing versus injection molding? Injection molding is a very well established technology. It’s well understood, very precise, and very fast. It’s cost effective for most things that are made in the world. So, 3D printing is probably not going to displace injection molding in my lifetime. But you have lots of applications where either the part is very complex or you want to design the part to be complex for functional reasons — either you want to lightweight it or there’s certain aspects of the part that would be really hard to mold. 3D printing has advantages there because it can print lots of geometries that you can’t mold.

Two would be around volume. It’s really an economics argument. If you’re going to make 100 million of something, you’re probably going to injection mold. You’re going to go through the effort to design the mold, even if it’s hundreds of thousands of dollars. That’s just the math, the economics. But if you’re making 5,000 parts or 10,000 parts or one part, that’s where the math tends to 3D printing because you have more flexibility, you don’t have the tooling costs, you can start almost immediately, and you don’t have to wait that six to 12 to 18 weeks to get the mold. So, usually the decision comes around how fast can you print parts and what the volume economic math comes out to be.

What are the next steps in the evolution of ESD materials and microprecision 3D printing?

Ivanova: In the resin realm, at least in curable ESD materials, we’re just scratching the surface. Filaments were there with carbon fiber or carbon black laser sintering powders on the market for quite some time. However, when resins appeared, I think we are taking advantage of better surface quality and intricate details, something that processes like FFF or laser sintering cannot achieve. That is a big deal in a lot of industries and for a lot of customers we’ve spoken to. Even on large 12- or 10-inch parts, the requirements of a surface finish turned them away from additive because the only option that was available until maybe the last couple of years was FFF, and it just didn’t hit the mark for those kinds of requirements.

The reason I’m saying we are scratching the surface, at least in the resin realm, is because as John mentioned, machining and molding are acceptable methods, well known, and relied on for so many years. We have to break the mold of a mold-maker and make a case for additive. And back to John’s point about when you make one part or 5,000 parts, additive makes sense from economical perspective. We also as a community hyped it up a lot. There is a educational piece when it actually make sense to manufacture parts additively, whether it’s small parts or large parts or not. But in ESD, it’s this market penetration and talking to customers that traditionally use injection molding and machining for fabricating components. We just started getting on their radar with ESD-safe resins that can fulfill the requirements for surface finish, part tolerances, and intricate features. And, as John mentioned, the new product introduction cycle speeds up because they can start almost immediately.

Kawola: Olga brought up a good point. There’s half a dozen different flavors of 3D printing, from filament extrusion to sintering with powder to some of the photopolymer-based technologies that BMF is part of. Historically, the materials that you could get from extrusion or sintering were, on average, better in terms of mechanical properties and creating end-use parts that are typically stronger. But there has been a significant improvement in the availability of photopolymer resins. Mechnano is a great example. There’s a number of different companies out there pushing the technology.

But this has only happened in the last five plus years. Five years ago, if you asked me if you could make functional parts on a stereolithography machine or photopolymer platform, I would say that the parts are beautiful, they’re the highest resolution, and they’re smooth, but I’m not sure they could be functional. Here in 2023, that’s not true anymore. More and more, there’s development from companies like Mechnano and others to get the best combination of functional materials and the accuracy and surface finish. And in some cases, a lot of the photopolymer platforms are faster and become more viable as production technologies because speed equals cost.

This is a continuum, and it certainly has happened over the last 10 years. Materials get better, machines get faster, machines get easier to use. Even processing power for computers has changed everything in terms of processing files or deploying real-time quality control or scanning. You might have had that technology, but you didn’t have the processing power five or 10 years ago. But now you do, so that’s not the gate. But these things don’t happen overnight. As the technologies get better, more companies will adopt this as a manufacturing method.

3D printing is pretty well understood and used as a prototyping method. That’s been true for 25 years. People forget that is still the killer app. The fact that you have a machine in your office and can get a part in half a day for $5 has been immensely valuable for most engineers and designers. It’s pretty much the norm now. That wasn’t the norm 15 or 20 years ago, but most companies making something physical are probably exposed to 3D printing in some way, so that will continue. But more adoption will come with manufacturing, which just takes time because parts need to be equivalent to what they are today, the math needs to make sense, and you have to overcome the risk calculation in terms of switching from something well understood to something new.

Boston Micro Fabrication
bmf3d.com

Mechnano
mechnano.com