Introduction to 3D Printing Circuit Boards

3D printing technology has revolutionized manufacturing and prototyping in many industries. In recent years, advances in 3D printing have enabled the ability to 3D print functional electronic circuits and circuit boards. This emerging technology, known as 3D printed electronics, allows designers and engineers to rapidly prototype printed circuit boards (PCBs) and electronic devices faster and at lower costs compared to traditional PCB fabrication methods.

The ability to 3D print circuit boards offers several advantages:

• Faster turnaround times (hours vs days/weeks)
• Lower costs for prototyping and low volume production
• Ability to create complex 3D circuit geometries not possible with standard PCBs
• Streamlined, software-driven design and manufacturing workflow
• Potential for multi-layer and multi-material 3D circuits

In this article, we’ll take an in-depth look at the current state of 3D printing circuit boards, including the technologies, materials, software tools and applications. We’ll explore how 3D printed electronics are enabling faster, more agile hardware development and discuss what the future may hold for this exciting field.

How 3D Printed Circuit Boards Work

There are a few different methods that have been developed for 3D printing functional electronic circuits and PCBs:

Fused Deposition Modeling (FDM)

Fused Deposition Modeling is the most common and accessible 3D printing technology. FDM 3D printers work by extruding molten thermoplastic through a heated nozzle to build up objects layer by layer. To 3D print circuits with FDM, conductive thermoplastic filaments are used. These filaments are made by infusing standard thermoplastics like PLA or ABS with conductive materials like carbon, graphene, or metal particles.

The FDM 3D printer deposits traces and pads of the conductive material to form circuit patterns, while non-conductive thermoplastic is used for the insulating substrate. Passive components like resistors and capacitors, as well as wires and other connectors can be embedded during printing or added afterwards.

Some benefits of FDM for 3D printed electronics include:

• Low cost and accessible
• Multi-material capabilities (conductive and insulating materials in the same print)
• Enables flexible and stretchable circuits

Limitations include:

• Lower conductivity than etched copper PCBs
• Requires speciality materials that can be expensive
• Lower resolution and surface finish than other methods

Stereolithography (SLA) and Digital Light Processing (DLP)

SLA and DLP are photopolymer-based 3D printing technologies that use UV light to cure and harden liquid resin into solid parts. These technologies offer very high resolution and smooth surface finishes.

To 3D print circuits, a UV curable resin is mixed with conductive particles like silver nanoparticles. The photopolymer binds the conductive particles together when exposed to light. Insulating sections are printed with non-conductive resin.

Advantages of SLA/DLP include:

• High resolution and smooth surfaces
• Enables complex, detailed circuit geometries
• Good mechanical properties

Disadvantages include:

• Requires speciality conductive resins which are expensive
• Limited material options compared to FDM
• Post-processing required to remove support structures

Inkjet and Aerosol Jet Printing

Inkjet is a material jetting 3D printing process that deposits tiny droplets of material to build up parts. Conductive inks containing metal nanoparticles like silver are used to print circuit traces and pads.

Aerosol Jet Printing is similar, but uses a focused aerosol mist of the conductive ink to “spray” circuits on 3D surfaces. This allows printing circuits on curvy and irregular shaped objects.

Benefits of inkjet and aerosol jet printing include:

• Very high resolution (down to 10 microns)
• Can print on a variety of substrates including 3D surfaces
• Thinner, more compact circuit traces than FDM or SLA
• Higher conductivity than FDM or SLA

Limitations include:

• High costs for printers and inks
• Relatively slow print speeds
• Complex post-processing steps like thermal sintering required

Materials for 3D Printed Circuit Boards

A variety of materials are used for 3D printing functional circuit boards, primarily thermoplastics and photopolymers infused with conductive particles. Here are some of the most common:

Conductive Thermoplastic Filaments for FDM

Material	Properties	Applications
Conductive PLA	Biodegradable, low-cost	Prototyping, low-power circuits
Conductive ABS	Strong, heat-resistant	Structural electronics, wearables
Carbon-filled Nylon	Very strong, flexible	High-performance electronics
Metal-filled Composites	Higher conductivity	Antennas, shielding, PCB hybrid

Conductive Photopolymer Resins for SLA/DLP

Material	Properties	Applications
Silver-filled Resin	High conductivity	High-frequency circuits, sensors
Copper-filled Resin	Lower cost than silver	Low-power electronics
Carbon-filled Resin	Resistive properties	Transducers, sensing elements

Conductive Inks for Inkjet/Aerosol Jet

Material	Properties	Applications
Silver Nanoparticle Ink	High conductivity	Printed antennas, RFID, touchscreens
Copper Nanoparticle Ink	Lower cost than silver	Flexible/stretchable circuits
Gold Nanoparticle Ink	Biocompatible	Biomedical sensors and devices
Carbon Nanotube Ink	Transparent conductors	Solar cells, displays

The choice of material depends on the specific application, required electrical properties, mechanical durability, and post-processing considerations. Advanced and novel materials like graphene and liquid metals are also being researched for future 3D printed electronics.

Design Software for 3D Printed Circuit Boards

Designing 3D circuits and PCBs requires speciality electronic design automation (EDA) software. Some popular pcb design software tools that support 3D circuits include:

Autodesk Fusion 360

Fusion 360 is a cloud-based CAD/CAM platform that includes electronics and PCB design tools. It has an add-in called Fusion 360 Electronics which allows you to design 3D PCBs and integrate them with mechanical CAD models. The 3D PCBs can be designed with flexible and rigid-flex substrates.

Altium Designer

Altium is a professional PCB design suite used by many electronics engineers. Recent versions include tools for designing 3D PCBs and integrating them with MCAD models. It has a 3D modeling engine that lets you define custom 3D PCB shapes and sizes.

Eagle

Eagle is a popular PCB design program owned by Autodesk. While primarily for 2D PCBs, recent versions have added support for 3D PCBs. The Eagle 3D Viewer allows placing components in 3D space and visualizing the board in 3D.

KiCAD

KiCAD is a free and open source electronics design suite that supports 3D PCB design and visualization. It has a 3D viewer for rendering the PCB in 3D and tools for exporting 3D models.

Printed Electronics Specific Software

There are also some speciality software tools emerging for designing 3D printed electronics:

• Voxel8 Developer’s Kit – Software for Voxel8’s electronics 3D printer
• Nano Dimension DragonFly Pro – Software for Nano Dimension’s inkjet PCB printer
• Voltera V-One – Software for desktop inkjet PCB printer

The choice of design software depends on factors like the designer’s existing workflow and software ecosystem, price and feature set. Seamless integration between electrical and mechanical CAD is important for 3D circuit design.

Applications of 3D Printed Circuit Boards

3D printed circuit boards and electronics are enabling many new and exciting applications including:

Rapid Prototyping

One of the biggest benefits of 3D printing circuit boards is faster and lower cost prototyping. Hardware startups and electronics designers can quickly iterate PCB designs in-house without the long turnaround times and high costs of outsourcing to a PCB fabrication service.

Aerospace and Defense

The aerospace and defense industries are exploring 3D printed electronics for applications like lightweight, conformal antennas that can be integrated directly into aircraft or drone airframes. 3D circuits could also enable integrated wiring and cable harnesses to reduce weight.

Medical Devices

3D printing enables mass customization of medical devices tailored to a patient’s anatomy. 3D printed electronics could allow biosensors and other electronic components to be integrated into patient-specific medical devices and wearables.

Internet of Things (IoT)

The huge growth of IoT is driving demand for large numbers of low-cost, semi-custom sensor nodes and devices. 3D printing could allow for rapid customization of IoT hardware with embedded sensors and antennas.

Wearables

3D printing allows electronics to be embedded into custom-fit wearable devices and smart clothing. Flexible and stretchable 3D printed circuits could enable a new generation of comfortable, unobtrusive wearable technology.

Education and Research

3D printed circuits are a great educational tool for teaching electronics and PCB design. They allow students to quickly test out ideas and hold a physical circuit board in their hands. Many research labs are also using 3D printing to build experimental electronic devices and test new materials.

The applications for 3D printed circuit boards and electronics are still emerging, but the ability to rapidly prototype functional PCBs and create circuits in novel form factors will certainly enable many new electronic products and devices in the future.

Challenges and Future Outlook

While 3D printing circuit boards is a promising technology, there are still some challenges and limitations compared to traditional PCB fabrication:

• Lower resolution and conductivity than etched copper traces
• Higher material costs, especially for metal nanoparticle inks
• Requires speciality 3D printers and materials
• Difficult to manufacture at volume
• Parts often requires post-processing steps like cleaning and sintering

Despite these challenges, the capabilities of 3D printed electronics continues to advance. Print resolutions and conductivities are improving as new materials and processes are developed. Costs are coming down as the technology matures.

In the future, 3D printing could enable a new generation of electronics with characteristics like:

• Flexible, stretchable and wearable circuits
• Circuits seamlessly integrated into mechanical parts and housings
• Complex multi-layer circuits with intricate 3D geometries
• Embedded components like antennas, sensors and batteries
• Bio-compatible electronics for medical implants
• Sustainable, recyclable printed circuits

Ultimately, 3D printing is democratizing electronics manufacturing and enabling hardware developers to innovate faster than ever before. As the materials and technology continue to evolve, 3D printed circuit boards will certainly play a growing role in electronics prototyping and manufacturing.

Frequently Asked Questions

What is 3D printing circuit boards?

3D printing circuit boards refers to fabricating functional electronic circuits and PCBs using additive manufacturing technologies like FDM, SLA and inkjet printing. Conductive materials are deposited to form circuit traces, pads and other features on an insulating substrate.

What are the benefits of 3D printing circuit boards?

Some key benefits include:
– Faster turnaround times (hours vs days/weeks with traditional PCB fab)
– Lower costs for prototyping and low-volume production
– Ability to create complex 3D circuit geometries
– Streamlined digital design and manufacturing workflow

What materials are used to 3D print circuit boards?

The most common materials are conductive thermoplastics (like metal-filled PLA) for FDM printers, conductive photopolymer resins (silver-filled) for SLA/DLP, and conductive inks (metal nanoparticle) for inkjet printing. The substrate is typically a non-conductive plastic.

How do 3D printed circuit boards perform compared to regular PCBs?

In general, 3D printed circuits have lower resolution and conductivity than etched copper PCBs. However, 3D printing allows circuits to be fabricated in complex 3D shapes and on flexible substrates which is difficult with normal PCBs. 3D printed circuits are best suited for prototyping and low-power applications.

What is the future outlook for 3D printed electronics?

3D printed electronics is a rapidly advancing field with a promising future. As print resolutions, material properties and costs improve, 3D circuits will find more uses in industrial, medical, consumer and IoT applications. 3D printing will enable innovative new electronic products with unique form factors, mechanical integration and materials. The technology is still emerging but offers huge potential for accelerating innovation in electronics design and manufacturing.