Trends in 3D Printing for 2020

In-situ monitoring

A process called in-situ monitoring is now built in to many high-performance platforms. Originally, it allowed manufacturers to see snapshots of their layers as they were built so they could identify potential issues that may not be visible in the final part. Products like Sigma Labs PrintRite3D ® combine software and hardware for monitoring 3D metal prints as they are built. This is significant if a 3D print is for aerospace or automotive applications, where a small defect could have huge liability. Some 3D printing platforms can even use take in-situ monitoring to the next step by steering corrective actions during the print if the monitored layer was not behaving as predicted. This reduces scrap and increases part quality.

In-situ monitoring has transformed HP’s Multi Jet Fusion’s technology by not only providing print feedback, but also by providing data-driven improvements and parameter upgrades across the entire printer product line. This means that the more parts that are built on the HP platform, the better all platforms will get at building parts through automatic feedback systems.

Novel fusion on filament-based systems like fused deposition modeling (FDM) and fused filament fabrication (FFF) can also produce isotropic properties. This can happen by using a jetted material between layers or even manipulating material properties to influence fusion. RIZE ™ has 3D printers that deposit specially formulated agents between layers. These agents can either enhance the layer bond or promote release for features like a support structure. Fortify has built a printer that uses a composite in its materials that can be manipulated in the melt state. This process, called Fluxprint, uses a magnet to directionally align small fibers as the layers are melted and fused, creating custom mechanical properties and greatly reinforcing Z-adhesion. Essentium has its flashfuse filament technology which electrically welds layers to produce significantly higher Z-strength.

3D contouring is another option for filament-based 3D printing, and was demonstrated recently by researchers at the University of Hamburg. This method deviates from the typical method of making a stack of 2D flat layers to build a model and instead, builds non-planar layers without a defined vertical direction. This allows mechanical features to retain their strength regardless of direction. In metal 3D printing processes, such as directed energy deposition (DED), the build substrate is typically held on a moving platform, allowing the material to be deposited in freeform. BeAM, a producer of DED equipment, has highlighted DED as a way to deposit materials for part repair as well as producing near-net-shape parts from scratch.

Innovations in 3D printing technologies such as continuous 3D printing, novel fusion on filament-based systems, and 3D contouring have opened up the possibility of isotropic parts to bring greater structural strength to parts.

Carbon DLS has expanded the possibilities of rubber-like parts retaining both durability and elasticity with elastomeric polyurethane (EPU) and urethane silicone (SIL) materials. These are compounded, printed, then cured for end-use properties. Additionally, thermoplastic urethanes like TPU and TPE have shown promise of demonstrating these physical properties using fused deposition modeling (FDM) as well as powder bed fusion processes like selective laser sintering (SLS) and HP Multi Jet Fusion (MJF). However, they often do not fulfill surface finish requirements to go beyond prototyping.

2020 may be the year of true silicones, offering not only flexibility, but also the biocompatibility, transparency, and high-heat resistance that you may be familiar with for many household products. Room-temperature vulcanized (RTV) silicones can be printed with extrusion-based platforms like ACEO’s product line, or may even be suspended without support structures like Picsima’s platform. There is a lot of innovation in the 3D printed elastomer space so keep your eyes peeled!

Metal binder jetting and metal deposition are novel materials that are making a comeback. Binder jet and plasticized metal processes have been around for decades; these processes stick material together in a green-state shape, and then typically go through post-processing to create a functional part. Why is this news? Because these processes have a high potential of disrupting the current metal 3D printing market, as metal binder jetting and metal deposition green parts are typically cheaper and require less ventilation and handling precautions during printing.

Post-furnace finishing also has the promise of creating isotropic part features and self-correction in metal crystallization or voids. The key players in this space are ExOne, Desktop Metal, HP, and Markforged. Each one of these companies offers direct binder jet solutions and work cell options. Markforged and Desktop Metal also offer a machine that behaves similar to fused deposition modeling, where a rod of plasticized metal is extruded in a planar pattern, growing the green-state part from bottom to the top. All these processes are able to draw on lessons learned from metal injection molding (MIM), which has been used to mass-produce small, detailed metal components with characteristics like metal stock.

3D printed circuit boards have been making waves in additive manufacturing since the introduction of Nano Dimension’s Dragonfly platform. Conceptually, the process is similar to PolyJet, where multiple materials can be deposited in the same print. In a dual-material print, one of the materials can have similar properties to a circuit board while the other can acts as a conductive layer called a “trace.”

With IoT and the proliferation of electronics, the need for printed circuit boards (PCBs) has never been more relevant. Building PCBs is relatively established in the industry, but it does have its own design constraints because inherently, PCBs are layered. Conductive traces typically require a feature called a “via” to continue between layers, and components are almost always on the top or bottom. 3D printing circuit boards opens up opportunities to embed electronics by design, route traces in 3D (including trace diameter), and build more conformal features to optimize RF signal, antennas, or just keep the design compact. By blending the concept of the board and housing, 3D printed circuits can deliver new approaches to electromechanical design.

Surface finishes have always been an obstacle for end-use additive manufactured components. For processes like FDM, HP MJF, and SLS, there is a tradeoff between robust mechanical properties and coarse surfaces. Even with processes like metal 3D printing, there is often a need for significant manual or vibratory finishing to make the part smooth.

2019 introduced solutions other than vibratory finishing, such as the PostPro3D platform, launched by Additive Manufacturing Technologies (AMT), which can smooth and tint many 3D printed polymers in an automated, repeatable manner. Dyemansion, best known for its automated SLS dyeing machine, has also added surface finishing technologies to their lineup.

For metals, traditional finishing such as media tumbling could smooth out external features but often removes edge detail on the part. This is because tumbling abrades and removes surface. Novel processes like DLyte’s dry electropolishing uses alternating charges between anodes and cathodes in an electrolytic media base to homogeneously even out the material surface while retaining feature detail. By reducing acute stress junction on the part surface, 3D prints can achieve smooth surfaces on 3D prints to meet both cosmetic and strength requirements.

3D printing composites combine traditional tooling with 3D printing, and this process has gained momentum leading into 2020 particularly with Markforged’s desktop printer. Building composite parts typically enhances part stiffness and mechanical properties by incorporating materials like carbon fiber into otherwise flexible polymers. This is a play on traditional fiberglass layups, where fiberglass or carbon fiber sheet is cured with epoxy against a shaping tool. Because the fibers are inherently stiff, the formed geometry blends high performance with lighter weight.

Markforged’s printers incorporate layers of continuous fiber in selected layers of the part, providing significant stiffness in the XY direction. Other companies, like Continuous Composites, go a step further by having a continuous fiber across the entire print held in place by a thermoset material. Blending more traditionally sheet layup approaches with 3D printing methodology, Impossible Objects prints sections of the part on sheets and then post-compresses to cure into a net-shape part.

Innovations in 3D printed tooling will help bridge the gaps between traditional approaches for manufacturing and rapid prototyping. Beyond building a mold cavity or insert, 3D printed components can have specific features that enhance mold performance. Conformal cooling is the most relevant example of how metal 3D printing can add utility to traditional mold making, and with hybrid approaches stated above, there is even more opportunity for plug-and-play tooling operations.

ColliderTech, has approached 3D printed tooling with a process to print a cavity for compounded resins like urethanes and epoxies. ColliderTech prints the cavity with features that aid material injection and curing. This results is a casted part without the need to build a silicone or rigid tool. Because much of the expense in urethane casting and RTV molding is the tool cost, this process could significantly decrease entry prices for high-performance components.