The Role of Atomic Force Microscopy (AFM) in 3D Printing

“Park Atomic Force Microscopy (AFM) plays an important role in our 3D printing projects in the laboratory. This powerful tool is capable of looking at the surface profile of 3D printed objects created by different 3D printing technologies in nanometer range.”

The 3D printing industry is expected to play a key role in the next industrial revolution, promising to transform existing industries while also creating new and unexpected ones.

Recent studies show that 3D printing is one of the fastest growing industries in the global economy, sitting at an estimated $4 billion in 2014. Predictions for the future show that, by 2025, the industry could reach $49 billion following predictions that 3D printing will soon be 50% cheaper and 400% faster.

One of the most important questions to ask is how quickly manufacturers can adapt to new 3D printing technologies that will require investment and retraining. Experts predict expansion in the use of 3D printing for production parts in the next three to five years in 93% of manufacturers. At the same time, 60% of manufacturers are expected to double their 3D printing use in two to five years.

3D printing started as a way for creative hobbyists to build things, and has since grown into a well-established additive manufacturing (AM) technology. To date, 3D printing has made its way to numerous manufacturing industries, such as electronics manufacturing, bioengineering, food fabrication, and many more.

3D Printing of Electronics

3D printing technologies have penetrated the electronics manufacturing sector thanks to the many innovations they bring. One such innovation is new control systems and techniques, such as inkjet and aerosol printing, which are mainly used for fabricating homogeneous structural electronics. The potential of 3D printing is great in both the electronics fabrication industry, and in terms of fabricating multiple layer complex electronics.

An important question to ask is whether 3D printing can become the most applicable method to mass produce electronics. What currently works best is incorporating the traditional method of ‘picking and placing’ when building electronics, and incorporating the latest 3D printing technologies into this preexisting technique. However, in order to reduce the whole volume of a typical manufactured device, there should also be a reduction of the space occupied and the materials used to build it. In the future, the more practical approach would be to embed the electronic components with conductive interconnects within a three-dimensional substrate. The result would be a stronger and more space-saving model.

“According to the 2016 Markets and Markets analysis report, printed electronics, in general, was considered to have a market value of 3.13 billion US dollars at the end of 2015 with a potential to reach 12.10 billion US dollars in the coming decade. But for 3D-printed electronics alone, it was valued 20 million US dollars in 2015 according to Harrop, the director of IDTechEx research firm. Asia Pacific market accounts the largest piece of the market in 2016 where the centers of electronics manufacturing are located in China, South Korea, Japan, and India; therefore, advancing the demand for printed electronics in the said region. Europe, on the other hand, holds the majority of research and development activities, and countries such as UK, Netherlands, and Finland are directing the printed electronics research in the region.”

One company that has embraced the idea of mass producing electronics using 3D printing is Optomec (who also pioneered Aerosol Jet printing). What separates Optomec from other companies is the fact that Optomec does not outsource the manufacturing of their machine parts (e.g. print heads). Instead, Optomec manufactures their own, using open systems designed for compatibility.

Optomec makes their print heads compatible with most CNC machines by making it possible for them to be customized to any integrated 3D printing systems in different production settings. This exceptional strategy allows Optomec to use commercially available inks, instead of using only what their proprietary formulation allows.

The main design focus of Optomec is on printing specialized antennas and sensors. Some of their printings include a 3D sensor for detecting expansion or shrinkage of a turbine. They also have printed interconnects on integrated circuits (ICs) that serve as an alternative to wire bonding process.

The Aerosol Jet printing mentioned earlier is considered superior to existing traditional methods of printing. For example, it allows for the direct printing of antennas on any given surface shape. This is known as “conformal printing,” and it does not require the use of injection molding and laser-based directed printing. Due to all the features mentioned, Optomec’s Aerosol Jet system is considered to be a crucial player for the realization of mass production of 3D printed electronics.

Conductive polydimethylsiloxane (PDMS) has been successfully 3D printed by using a unique embedded 3D printing (e-3DP) method, as shown:
a) A photograph of a glove with embedded strain sensors produced by e-3DP.
b) Electrical resistance change at different hand gestures.
c) A three-layer strain and pressure sensor in the unstrained state (left) and stretched state (right).

Optomec Aerosol Jet and OEM Neotech Services Successfully Printed a 3D Printed Sensing Circuit Composed of a Plastic Tank with Circuitry on It

In the sphere of electrical engineering, there have been efforts made to replicate the physical characteristics of metals via 3D printing functionalized high-performance polymers for applications that require rigidity and the electrical properties of metallic materials.

One example of this is electric motors, which are composed of metallic parts and usually have the aforementioned properties to be able to effectively and efficiently transform electrical energy to mechanical energy, or vice versa.

DC voltage is applied in the electrodes in order to make the rotor spin at a rate proportional to the electric field created by the electrodes, creating what is known as a capacitor motor.

The transition to building an object with near-metallic properties using 3D printing and functionalized materials has allowed 3D printing technology to set new benchmarks in the manufacturing process field.

This photo shows a spinning 3D printed electrostatic motor. The rotor blades and the electrodes were made of processed conductive PA12 with reduced GO, while the base was printed using pure PA12.

3D Printing of Silicone

The printing of paste mixtures or viscous solutions will become a popular trend in the near future, along with the need for building freedom for complex shapes and geometries when manufacturing flexible materials. Flexible electronics have exhibited a range of functionalities – some of which have been crucial in the manufacturing of solar cells, displays and LEDs, sensors, and thin-film transistors. Flexible electronics have boomed in popularity due to their application within flexible displays and wearable electronics.

Conductive polydimethylsiloxane (PDMS) has been successfully 3D printed with the use of a unique embedded 3D printing (e-3DP) method, as shown.

a) A photograph of a glove with embedded strain sensors produced by e-3DP.

b) Electrical resistance change at different hand gestures.

c) A three-layer strain and pressure sensor in the unstrained state (left) and stretched state (right).

Park Atomic force microscopy (AFM) plays a crucial role in printing 3D projects in the laboratory. AFM is capable of looking at surface profiles of 3D printed objects created by different 3D printing technologies at nanometer range.

An example of this is the high-resolution paste extrusion technique, through which the accurate profiling of the width of the extruded strands and the height of the layers of a 3D printed silicone adhesive becomes possible by measuring the consistency of the resolution set throughout the 3D printing process.

Furthermore, defects such as shrinkage can be examined in greater detail, which is made possible due to the build parameters of the 3D printers. Important parameter adjustments are also identified, which helps to optimize the build process and reduce the number of defects found in 3D printed objects.

AFM is different from other microscopy techniques as it does not require treatment of the sample. Such treatment can cause damage to a rising technology in food fabrication, known as extrusion-based food printing, which uses the same mechanism as paste extrusion printing. This method is specifically designed for building food products using edible materials in a layer by layer manner.

Research has been conducted in 3D printing food products, with the overall aim of being able to control nutritional data, texture and composition.

This 3D printing technique focuses on the tenability of nutritional content in the food product and uses 3D printing extrusion mechanisms. 3D printing has started to transform the way food is designed and fabricated.

Food fabrication

Schematic of 3D Printing of Food with Nutritional Control

Sustainability

Predictions for the future of 3D printing show that it could grow to 500% in the next few years, and reach $16.2 billion by the end of the current year alone. The evidence for this lies in the rise of 3D printer and material sales worldwide. “It has now moved from a new and much-hyped, but largely unproven, manufacturing process to a technology with the ability to produce real, innovative, complex and robust products.“

This makes the 3D printing one of the fastest growing markets to date. Its success would be a result of an amalgamation of factors, such as the endless possibilities of customization, the ability to suppress replacement buying, curbing material waste in the manufacturing process, the idea of free-sharing digital designs online, and lessening carbon emissions by eliminating the need for transporting actual products.

Nevertheless, there are still issues in 3D printing that need to be solved, such as sustainability. There are several downsides to achieving true sustainability. One example is how power consumption increases as production rises.  Other issues include: a rise in single-use plastic production and usage, product obsolescence, and intellectual property theft. The significant increase of product consumption could raise ethical questions surrounding the environment and how the products are ultimately used (e.g. guns, food restrictions and more).

With the observance of circular economy as a basis for writing energy and waste management policies, initiatives around the world are being concretized towards reducing plastic wastes by recycling them with the aid of 3-D printing technologies. Despite the inherent uncertainties of such a new industry, lawmakers and scientists are joining forces to achieve sustainable developments in 3D printing.

There is a high possibility that additive manufacturing will soon surpass traditional manufacturing. When that time comes, both consumers and manufacturers are expected to take responsibility for the lives of the future generation, not just for the sustainability of the technology itself.

In 2014, the 3D printing industry was estimated to be at $4 billion. With new predictions that 3D printing will be 50 percent cheaper and up to 400 percent faster, the industry could reach $49 billion by 2025.

References and Further Reading

1. B. Cook, B. Tehrani, J. Cooper, S. Kim, and M. Tentzeris, "Integrated printing for 2D/3D flexible organic electronic devices," Handbook of Flexible Organic Electronics, pp. 199-216, 2015.
2. G. Weiderrecht, Handbook of Nanofabrication, Elsevier, 2009.
3. R. Mosses and S. Brackenridge, "A novel process for the manufacturing of advanced interconnects," Circuit World, vol. 29, no. 3, pp. 18-21, 2003.
4. D. Zhao, T. Liu, Z. Lin, M. Zhang, R. Liang, and B. Wang, "Fabrication and characterization of aerosol-jet printed strain sensors for multifunctional composite structures," Smart Mater. Struct., vol. 21, no. 11, 2012.
5. B. Lu, D. Li and X. Tian, "Development Trends in Additive Manufacturing and 3D Printing," Engineering, vol. 1, pp. 85-89, 2015.
6. Y. Shirasaki, G. Supran, M. Bawendi and V. Bulović, Nature Photonics, vol. 7, pp. 13-23, 2012.
7. E. Macdonald, R. Salas, D. Espalin, M. Perez, E. Aguilera, D. Muse and R.
8. Wicker, "3D Printing for the Rapid Prototyping of Structural Electronics," IEEE Access, vol. 2, pp. 234-242, 2014.
9. E. Macdonald, "Integrating stereolithography and direct print technologies for 3D structural electronics fabrication," Rapid Prototyping Journal, 2012.
10. J. Lewis and B. Ahn, "Three-dimensional printed electronics," Nature, vol. 518,pp. 42-43, 2015.
11. L. Teschler, "Your next circuit design could be fabricated on a printer," 13 November 2015.
12. M. Clinch, "3D printing market to grow 500% in 5 years," 1 April 2014.
13. L. Federico-O’Murchu, "How 3D printing will radically change the world,"11 May 2014.
14. A. Mitchell, "3D Printing: Adding a Sustainable Dimension to Modern Life," February 2018. [Online]. Available: https://en.reset.org/knowledge/3dprinting-adding-sustainable-dimension-modern-life-02262018. [Accessed 29 March 2018]

This information has been sourced, reviewed and adapted from materials provided by Park Systems Inc.

For more information on this source, please visit Park Systems Inc.