How a 3D Printer Works and What It Is Used for

3D printing, also known as additive manufacturing, is defined as a process in which a digital file is used to create a three-dimensional solid object. In the 3D printing process, sequential layers of material are laid down by the ‘printer’ until object creation is completed. This article covers the working, software, and applications of 3D printing.

3D printing, also known as additive manufacturing, is a process in which a digital file is used to create a three-dimensional solid object. In the 3D printing process, sequential layers of material are laid down by the ‘3D printer’ until object creation is completed.

3D-printed objects are created through an additive process, where the printer places layer after layer of material until the desired thing is ‘printed’. Each layer can be considered a finely sliced cross-section of the printed item. With 3D printing, users can produce complicated shapes without consuming as much material as traditional manufacturing methods require.

The operation style of 3D printing is the opposite of ‘subtractive manufacturing’, where the material is cut out or hollowed using equipment such as a milling machine. Conversely, additive manufacturing does not need a mold or material block to create physical objects. Instead, it stacks layers of material and fuses them together.

3D printing offers swift product creation, low expenses for the initial fixed infrastructure, and the ability to create complicated geometries using several material types, something traditional manufacturing solutions might not be capable of as efficiently.

Generally associated with the Do It Yourself (DIY) culture of amateurs and hobbyists, 3D printing has grown to include commercial and industrial applications. For instance, engineers today often use 3D printers for prototyping and creating lightweight geometric objects.

The origins of 3D printing lie in ‘rapid prototyping’. When the base technology was first invented in the 1980s, the term was used to describe it because, at the time, 3D printing was only suitable for creating prototypes rather than production components. In fact, the original intent of its creation was simply to accelerate the development of new products through swift prototyping.

Interestingly, the technology did not garner much interest when it was first introduced. In 1981, Japan's Hideo Kodama filed the first patent for a machine that leveraged UV light for curing photopolymers. Three years later, French inventors Olivier de Witte, Jean Claude André, and Alain Le Mehaute jointly filed a patent for a similar technology. Both patents were abandoned, with General Electric saying the ‘latter lacked notable business potential’.

It was in 1984 that American inventor Charles Hull filed a patent for an ‘Apparatus for Production of Three-Dimensional Objects by Stereolithography’. He invented the STL file and founded 3D Systems three years later, in 1987.

Within the same decade, significant strides were made in the US 3D printing space, with patents filed for selective laser sintering (SLS) and fused deposition modeling (FDM). Desktop Manufacturing (DTM) Corp. and Stratasys were pioneering companies in the 3D printing space, founded around the same time.

After that, the industry transformed as rapid commercialization took hold of it. The first ‘3D printers’ were large and cost-intensive, with their makers competing to land contracts for industrial prototyping with large-scale automotive, consumer goods, health products, and aerospace manufacturers.

By 1987, 3D Systems had introduced the first commercial-grade SLA printer; in 1992, Stratasys and DTM released the first commercial FDM and SLS printers, respectively. The first metal 3D printer was introduced in 1994 by Electro Optical Systems (EOS), a German enterprise.

By the dawn of the new millennium, companies in the 3D printing space were competing fiercely for profits. Progress in materials science and the lapse of numerous patents increased the affordability of 3D printing.

Soon, thanks to the strides made in the 3D printing space, manufacturing processes were not exclusively owned by enterprises backed by heavy machinery and capital. Today, 3D printing has transformed into a cutting-edge solution for creating many different types of production components.

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The ISO/ASTM 52900, related to the general principles and terminologies in additive manufacturing, categorizes 3D printing processes into seven distinct groups. Each type of 3D printing works a little differently.

The time taken to print a 3D object depends on the type of printing, the output size, the type of material, the desired quality, and the setup configuration. 3D printing can take anywhere from a few minutes to a few days.

The different types of 3D printing are:

In powder bed fusion (PBF), thermal energy, in the form of an electron beam or laser, selectively fuses specific areas of a powder bed to create layers. These layers are built on one another until a part is made.

PBF may include sintering or melting processes; however, the primary operation method remains the same. First, a recoating roller or blade places a fine layer of powder on the build platform. Next, the surface of the powder bed is scanned using a heat source. This source selectively increases particle temperature to bind specific areas.

Once the heat source scans a cross-section or layer, the platform descends to let the process be repeated for the next layer. The final output is a volume with fused parts, with the surrounding powder remaining unaffected. The platform then ascends to allow retrieval of the completed build. Powder bed fusion includes several standard printing methods, such as selective laser sintering (SLS) and direct metal laser sintering (DMLS).

SLS is regularly leveraged for manufacturing polymer parts for prototypes and functional components. SLS printing takes place with the powder bed as the sole support structure. The lack of additional support structures allows for the creation of complex geometries. However, produced parts often feature inner porosity and a grainy surface and generally require post-processing.

SLS is similar to selective laser melting (SLM), electron beam powder bed fusion (EBPBF), and direct metal laser sintering (DMLS). However, these processes are used for creating metal parts and rely on a laser for fusing powder particles, one layer at a time.

DMLS increases the temperature of the particles only up to the point of fusion, whereby they combine at a molecular level. On the other hand, SLM completely melts metal particles. Both these techniques are heat-intensive and thus require support structures. Once the process ends, the support structures are removed using CNC machining or manually. Parts are then thermally treated to address residual stresses during post-processing.

These metal 3D printing techniques create components with high-quality physical properties, sometimes even more robust than the base metal used. The surface finish is often excellent as well. In terms of material, these techniques can process metal superalloys and ceramics that can be hard to use in other processes. However, both DMLS and SLM are cost-intensive, and the system's volume constrains the output size.

VAT photopolymerization can be split into two methodologies: digital light processing (DLP) and stereolithography (SLA). Both these processes create components one layer at a time by using a light source to selectively cure liquid material (usually resin) stored in a vat.

DLP works by ‘flashing’ an image of each complete layer onto the surface of the liquid in the vat. On the other hand, SLA relies on a single-point UV source or laser to cure the liquid. Excess resin has to be cleaned off the output once printing is completed, after which the item must be exposed to light to improve its strength further. Support structures, if any, will need to be removed post-processing, and one can further process the part to create a higher quality finish.

These methods are best-suited for output that requires high-level dimensional accuracy, as they can create intricately detailed items with an excellent finish. DLP and SLA are, therefore, well-suited for the production of prototypes.

However, these methods’ output is often brittle, making them less suited for functional prototypes. These parts’ color and mechanical properties are also likely to degrade in the sun's UV light, making them unsuitable for outdoor use. Finally, support structures are often required and might leave blemishes, which one can remove through post-processing.

Binder jetting works by depositing a fine layer of powdered material, such as polymer sand, ceramic, or metal, onto the build platform. After this, a print head deposits adhesive drops to bind these particles. The part is hence built layer by layer.

Metal parts must be thermally sintered or infiltrated with a metal that has a low melting point, such as bronze. Parts made of ceramic or full-color polymer can be saturated using a cyanoacrylate adhesive. Post-processing is generally required to finish the output.

Binder jetting has numerous applications, including large-scale ceramic molds, full-color prototypes, and 3D metal printing.

Material jetting is conceptually similar to inkjet printing. However, instead of inserting ink on paper, it uses one or more print heads to deposit layers of liquid material. Each layer is cured before the next layer is produced. While material jetting relies on support structures, they can be created using a water-soluble substance that is washable after the building is completed.

This highly precise process is well-suited for creating full-color parts using different material types. However, it is cost-intensive, and the output tends to be brittle and degradable.

In fused deposition modeling (FDM), a heated nozzle is used to feed a filament spool to an extrusion head. The extrusion head increases the temperature of the material, softening it before placing it in predetermined areas to cool. Once a material layer is created, the build platform descends and prepares for the next layer to be placed.

This process, also known as material extrusion, features low lead times and is cost-effective. However, its dimensional accuracy is low, and a smooth finish often requires post-processing. The output is also not well-suited for critical applications as it tends to be anisotropic, i.e., weaker in one direction.

Sheet lamination can be further classified into two technologies: ultrasonic additive manufacturing (UAM) and laminated object manufacturing (LOM). UAM has a low energy and temperature requirement and works by joining thin metal sheets using ultrasonic welding. It works with several metals, including stainless steel, titanium, and aluminum. On the other hand, LOM places layers of material and adhesive alternatively to create the final output.

This technique uses a laser, electric arc, electron beam, or another form of focused thermal energy to fuse powder or wire feedstock as it is placed. The process takes place horizontally to create layers, which are then stacked vertically for part creation. It is suited for different material types, including ceramics, polymers, and metals.

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The 3D printing space is heavily software-dependent, with programs required for everything from designing the output and slicing it into G-code to controlling the 3D printer. Let's check out the top 3D printing software across applications.

This solution by MatterHackers is an all-in-one printer host, slicer, and CAD software for desktops. Users can create new models in the CAD section and slice them. Once the model is ready to print, MatterControl 2.0 can be used to directly monitor and control printing via a USB connection or over a Wi-Fi module.

The software features an intuitive interface and allows users to explore a collection of geometric primitives that users can import into the print. These primitives can be dragged into position on the standard triangle language (STL) file to be printed and designated as support structures.

MatterControl also gives users access to advanced print configurations, making it ideal for end-to-end design, support preparation, slicing, and control. Enterprise users can upgrade to MatterControl Pro for even more valuable features.

This free, browser-based solution allows users to design printable 3D models and provides a starting place for practicing solid modeling. Its easy-to-use block-building feature enables users to form models using basic shapes.

Tinkercad has numerous guides and tutorials to help users create the desired designs, which can then be exported or shared easily. Its library gives users access to millions of files, allowing them to find and modify the required shape. Finally, it features direct integration with third-party printing services.

This free, open-source tool is well-suited for both newbies and advanced users. It is feature-rich and can be used for 3D modeling and sculpting, as well as for animation, rendering, simulation, video editing, and motion tracking. However, it has a steep learning curve.

This open-source solution is a comprehensive resin printing suite, an excellent file viewer, and optimized for layer repair and manipulation for masked SLA. It is compatible with PrusaSlicer, giving users access to numerous third-party MSLA printer profiles.

Twin-stage motor control (TSMC) is a crucial feature of UVTools, enabling tiered print speeds for different movement parts for each layer. This reduces print time and boosts the likelihood of print success.

Finally, UVTools allows users to create a custom resin layer cure time calibration print for testing new resins and setting the appropriate configuration for different layer heights.

This browser-based solution can be used to preview G-code without having to open the file in a full-capability slicer. Users simply need to upload the G-code file, and WebPrinter will show the tool pathing that the file will transmit to the 3D printer. It is a fast and simple method to view a potential 3D print output.

This open-source slicer is compatible with most modern 3D printers. Cura is well-suited for beginners as it is easy to use, swift, and intuitive. On the other hand, advanced users can leverage it to access 200 settings for refining prints.

Simplify3D is a powerful slicing tool for enhancing 3D print quality. It slices CAD into layers, corrects model issues, and showcases a user preview of the final output. Its premium features are handy for enterprise heavy-use 3D printers.

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Although 3D printing is not a recent invention, it has gained immense popularity in recent times across industries due to its newfound simplicity, efficiency, and cost-effectiveness.

The top applications of 3D printing are:

Construction is one of the significant applications of 3D printing. Concrete 3D printing has been explored since the 1990s as researchers sought a faster and cheaper way to construct structures. Specific applications of 3D printing in construction include additive welding, powder bonding (reactive bond, polymer bond, sintering), and extrusion (foam, wax, cement/concrete, polymers).

Today, large-scale 3D printers designed to print concrete are used to pour foundations and erect site walls. They are also capable of printing modular concrete sections for onsite assembly. These solutions allow for higher accuracy, more complexity, faster construction, and improved functional integration while lowering labor costs and minimizing waste.

In 2016, the first pedestrian bridge (12 meters long, 1.75 meters wide) was 3D printed in Spain using micro-reinforced concrete. A year later, the first fully 3D-printed residence was built in Russia. 600 wall elements were 3D-printed and assembled, after which, the roof and interiors were created for a total area of nearly 300 sq meters.

3D printing is also helpful in producing architectural-scale models. It is even being explored as a solution for constructing extraterrestrial habitats on the Moon or Mars, should the need ever arise.

In the case of traditional injection-molded prototyping, it can take weeks to produce a single mold that would cost up to hundreds of thousands of dollars. As established earlier in the article, the original purpose of 3D printing was faster and more efficient prototyping.

3D printing technology minimizes lead times in manufacturing, enabling prototyping to be completed within a few hours and at a small percentage of traditional costs. This makes it especially ideal for projects where users must upgrade the design with every iteration.

3D printing is also suitable for manufacturing products that do not need to be mass-produced or are usually customized. SLS and DMLS are used in the rapid manufacturing of final products, not just prototypes.

In healthcare, 3D printing creates prototypes for new product development in the medical and dental fields. In dentistry, 3D printing is also helpful in creating patterns for casting metal dental crowns and manufacturing tools for creating dental aligners.

The solution is also helpful for directly manufacturing knee and hip implants and other stock items and creating patient-specific items such as personalized prosthetics, hearing aids, and orthotic insoles. The possibility of 3D-printed surgical guides for particular operations and 3D-printed bone, skin, tissue, organs, and pharmaceuticals is being explored.

In aerospace, 3D printing is used for prototyping and product development. The solution is also critically helpful in aircraft development, as it helps researchers keep up with the strenuous requirements of R&D without compromising on the high industry standards. Certain non-critical or older aircraft components are 3D-printed for the flight!

Automotive enterprises, especially those specializing in racing automobiles, such as those used in F1, leverage 3D printing for prototyping and manufacturing specific components. Organizations in this space are also exploring the possibility of using 3D printing to fulfill aftermarket demand by producing spare parts as customers require rather than stocking them up.

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The term ‘3D printing’ encompasses numerous technologies and processes that collectively offer a wide range of capabilities for producing components using various materials. The key similarity across 3D printing types is the additive layer-by-layer production process where no subtractive methodology, molding, or casting is required. Applications of 3D printing are rapidly emerging across industry verticals as the solution becomes more effective and affordable and penetrates deeply and widely across sectors.

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Technical Writer