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The seven types of 3D technology have opened up a new world of opportunities in the technology and manufacturing industry.
The industry uses the term additive manufacturing (AM) process. During this process, a programmed digital format binds layers of material that develop into a solid and usable product.
3D printer-type technology is advantageous because it creates less waste than the traditional production of the same product.
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Primitive concepts surfaced in 1945 by Murray Leinster and again in 1950 by Raymond F. Jones. Johannes F. Gottwald patented his Liquid Metal Recorder in 1971.
In the current market, it’s possible to purchase 3D printers for $500.
3D printing technology defines a collection of 3D printing technologies and processes. To help standardize the 3D printing technology, the ISO/ASTM 52900 generalized the principles, fundamentals, and governing terminology.
Since the inception of 3D printer types, seven printing processes have dominated the technology. Although all 3D printing technologies are complex, here is a detailed yet easy-to-understand summary of their function.
The 7 3D Printing Technologies Types Explained
With the advancements in 3D printing, the industry branched into highly developed subcategories. Most people associate 3D printing with polymer components, and AM has a strong association with metalworking and end-use production.
Inkjets are an invention from the 1950s and saw use as recorders, not printers. However, Inkjet continued to develop from a single nozzle to complicated machines that employ thousands of nozzles in one pass.
The top seven categories also developed subsequent offspring, listed as the following:
- Material Extrusion
- Vat Polymerization
- Powder Bed Fusion
- Material Jetting
- Binder Jetting
- Direct Energy Deposition
- Sheet Lamination
Read on for the breakdown of the details of each subcategory.
Material Extrusion often uses plastic filament and forces the material through a heated nozzle. Since plastic melts at roughly 356 – 392℉ (180 – 200℃), the nozzle deposits the material on the designated platform following the predestined program outline.
Once the filament cools, it forms a solid, recognizable object and the predetermined shape. This process works well with metal paste, concrete, bio-gels, and other suitable substances. Plastic is the most prolifically used material in this process.
This process is also commonly used for food production, like chocolate, chocolate ganache, or pre-shaped candy. It shapes paste-like substances like purees, jellies, or mouses into exact shapes.
Material Extrusion at a Glance
- Uses materials like plastic filaments (PLA, ABS, Nylon, Carbon Fiber, PET, and others) and food materials (paste-like).
- Dimensionally accurate to within 0.5%.
- Practical usage in electrical components, forms, fixtures, and food.
- Pros include low cost of print production and material versatility.
Fused Deposition Modeling (FDM) or (FFF)
Material Extrusion technology is readily available and lower in price, making FDM modeling an excellent option for many businesses and private users.
In terms of usage, FDM is a relatively simple process. The desired material feeds from a spool through the heated printer nozzle that forces the melted material into the predetermined shape.
Of course, all the parameters, including the type of filament, temperature, and shape, are programmed into the 3D printer. The 3D printer will make several (as many as programmed) passes and build the product line (or layer) by line until the product is complete.
Support structures stabilize complicated products from collapsing as the texture is soft and pliable until it hardens.
The FDM industry extrudes many materials like clay and concrete into complex building parts. It can shape plastics into tools and toys. This technology can print organs from live cell extractions in a bio gel into medically advanced tools.
A light source is a prime component in vat polymerization. The light source directs its power onto photopolymer resin held in a vat.
This process allows the light to harden a layer of liquid plastic directly. As with other 3D printing technologies, the cycle repeats until the 3D part forms the specific dimensions.
Vat polymerization has three subcategories, which are Masked stereolithography (MSLA), Stereolithography (SLA), and digital light processing (DLP). What separates these processes is the type of light sources required to cure the resin.
Professional-grade 3D printer manufacturers employ several variations of vat polymerization. Some require patent applications to protect the engineering behind the process.
There are several SLA methods on the market.
- Digital Light Synthesis (DLS) by Carbon
- Programmable Photopolymerization (P³) by Stratasys
- Projection Micro-stereolithography (PµSL)
- Low Force Stereolithography (LFS) by Formlabs
- High Rapid Printing (HARP) by Azul 3D
- Lithography-based Metal Manufacturing (LMM)
- Digital Composite Manufacturing (DCM) (photopolymer with metal or ceramic fibers)
Vat Polymerization at a Glance
- Uses materials like photopolymer resins with transparent, industrial, biocompatible, and pliable for casting).
- Dimensionally accurate to .5%.
- Practical usage for injection molds (prototypes), dental fixtures, and jewelry molds.
- Pros include intricate detail replications and flawless finish.
SLA is a laser beam-based 3D printing technology. Patented in 1986 by founder Chuck Hull, SLA is a commercialized printing process using mirrors.
Galvanometers are mirrors that direct a laser beam across a vat of resin. They are also known as galvos. One mirror rests on the X-axis whistle the other is positioned on the Y-axis to project the beam onto the desired location. As a result, the laser beam quickly cures and hardens layers of the resin.
Digital Light Processing (DLP)
Very similar in design to SLA 3D printers, the digital light processors in DLP printers flash single or several images of a layer in one application.
This slightly more advanced technology uses square pixels on a digital projector screen. Each layer forms from voxels, or tiny rectangular blocks, when the light projects onto the resin. The LED (light emitting diode) or UV lamp focuses on the build platform using a digital micromirror device (DMD).
Masked Stereolithography (MSLA)
MSLA 3D printing technology also harnesses LEDs as a light source. When the UV light source penetrates the LCD screen, it projects a single layer as a mask.
Like its cousin DLP, the photomask uses square pixels to display the photomask digitally. The XY definition is independent of the zoom or scale range of the lens (like the DLP) and impacts the clarity of the print.
MSLA works by using individual emitters coordinated to control the output of light. Other DLP printers use single-light emission laser diodes or DLP, while MSLA can capture an entire layer simultaneously.
Related Vat Polymerization Print Technology
Vat polymerization technology continues to grow and advance. Several subcategories warrant investigation.
Powder Bed Fusion
Thermal energy makes a great partner in 3D printing, and powder bed fusion takes advantage of this source. In this process, the thermal energy sources create a fusion between powder particles from materials like plastics, ceramics, metals, and others inside the build chamber. This induced process builds solid objects one layer at a time.
Within a powder bed fusion printer, a calibrated device spreads a thin layer of powdered substance. Next, the blade or wiper applies the material, and the conducted energy combines to form a layer. The final step coats the product in unfused powder.
Powder bed fusion at a Glance
- Typical materials include thermoplastic powders like Nylon 6, 11, and 12 and metal powders created from steel, titanium, cobalt, aluminum, and ceramic powders.
- Dimensionally accurate to 0.3%.
- Used in parts manufacturing, ducting and other hollow applications, and small production runs.
- Pros include versatility for parts manufacturing, ideal for mechanical components, and complicated designs with numerous angles.
Selective Laser Sintering (SLS)
Sintering is a process that transforms a powdered substance into a solid or porous form. This process requires heat and compression without liquefying the substance.
SLS is emerging in the print technology market as an affordable and popular method since the original patents are expiring.
Using heat, the polymer powder’s temperature rises below the melting point. Next, a revolving blade or wiper smears the thin layer onto the build template. Each pass creates a solidified layer or cross-section.
Similar to SLA, a set of galvos (mirrors) trains the laser onto the optimum location programmed into the printer’s schematics. As each layer builds, the scanning device directs another layer of powder across the form and sinters it into the correct dimensions.
Micro-selective laser sintering (μSLS) is a perfect printing solution for scaled-down objects. μSLS is extremely useful for metal parts with sub – 5 μm resolution where nanoparticles of metal ink get coated onto an underlying surface (substrate) and dried to create a nanoparticle layer.
Selective Laser Melting (SLM) / Direct Metal Laser Sintering (DMLS)
DMLS and SLM are close relatives of SLS 3D printing but have more practical applications in the metal parts industry.
SLS heats a powder to the melting point, while DMLS heats the powder until it reaches a fusing point on a molecular level. SLM applies high-density laser technology to melt and fuse metallic powder components to create a nearly complete object (net shape). The part has a single melting point.
DMLS forms products from metal alloys, while SLM relies on pure single-element substances like titanium. DMLS and SLM technology also needs structural support to reproduce uniform effects. Any unused portions of support powder remain usable.
The DMLS and SLM print technology is vulnerable to warping. High temperatures during this process don’t melt the powder substances and create less stress on the product. These products undergo a heat treatment to reduce further strain on the product.
Electron Beam Melting (EBM)
EBM is a unique powder bed fusion process that depends on electrons, or a high-energy electron beam, to create the union between metal powder particles. This fusion process and a laser-focused beam skim across a thin layer of powder. As a result, it causes it to melt and solidify.
The superior electron beam used in EDM technology creates a higher energy density and advanced build speed. EDM is a vacuum technology that works well for conductive materials to create larger objects from bigger powder particles, thicker layers, and surface areas.
Multi Jet Fusion (MJF)
MJF is another powder bed fusion technology that shares similarities with binder jetting. This advanced 3D technology (2016) falls under the HP umbrella. HP used Inkjet printing, sprayable substances, material sciences, imaging, and precision engineering to advance MJF to its current state.
This technology uses multiple Inkjet heads during the printing operation and depends on separate nozzles to coat, distribute and heat the elements and move them in opposing directions. Using multiple heads allows the user to operate the system independently.
Once complete, an infrared heating mechanism maneuvers across the print surface and melts the layers together where the fusing agent was present. The characters treated with a detailing agent remain powdery and shed off.
The ingenuity of this process negates the use of support materials. The process works by submitting each new level of agent layer and material in unison while the previous layer retains its molten state and causes better cohesion.
In the final stage of the MJF printing, the powder bed moves to a processing station. The unfused powder inside this chamber is suctioned and reused, reducing waste.
Material jetting builds objects when photopolymers or wax substances cure under light exposure. The item forms as droplets of these materials deposit and cure on the build plate.
The primary use of material jetting is that it can accommodate various materials to create objects with different textures and colors.
Material Jetting at a Glance
- Suitable materials like Photopolymer resins are standard, moldable, transparent, and temperature resistant.
- Dimensionally Accurate to within 0.1 mm.
- Practical use in multi-color prototypes, injection mold-like prototypes, and medical products.
- Pros include delivery of high-quality surface finish, multi-color, and multi-material versatility.
- Cons include a fragile substance that’s not durable.
- Less cost-effective than SLA/DLP.
Material Jetting (MJ)
MJ printing works on the same principles as an Inkjet printer. However, instead of one layer like with Inkjet, a specific number of layers is programmed into the design to produce an actual product.
In this expedient process, the print head jets droplets of photopolymer and simultaneously solidifies them in the curing process using ultraviolet light. Each layer undergoes the same process, and the platform lowers at each phase until the product builds the programmed design.
The MJ printing quickly builds layers in a repeating line process and uses a multiple-point deposition. MJ shares its deposit, sinter, and cure process with similar printing processes but uses a point and line-wise deposit process.
MJ printers are versatile and fabricate multiple objects in a single line at optimum build speed, surpassing other 3D printers’ capability. Another unique feature of MJ printing is that the necessary support structure prints simultaneously using materials with disintegrative properties.
Drop on Demand (DOD)
DOD is an Inkjet printing process that relies on drops of a waxy substance and a dissolvable support component. The process follows a program design that jets the build material in a pointwise deposition in a cross-sectional pattern to shape the object with each additional layer.
A fly-cutter smooths each newly minted layer, ensuring the next layer has a flat surface. DOD printers are ideal for lost-wax casting, investment casting, and mold application patterns.
Related Material Jetting Print Technology
Subcategories of material jetting include nanoparticle jetting (NPJ) and color jet printing (CJP).
Similar to SLS 3D printing technology, binder jetting relies on a liquid bonding material that binds regions of a powder bed in a particular sequence. Binder jetting uses an initial powder layer to build a base. Whereas SLS engages laser or energy to sinter the powder, binder jetting slides over the powder surface and drops binding beads. These tiny beads are only 80 microns in diameter and fuse the particles into each layer of the designed object.
Binder jetting doesn’t use heat during its printing process. Instead, once the powder bed lowers, a new layer spreads over the freshly minted print surface and repeats until the object forms.
During finishing, the newly formed object is submersed in the powder to finish curing and develop into a strong product.
Binder Jetting at a Glance:
- Binder jetting is a unique process that binds without heat.
- Ideal for materials like sand, polymer, metal powders (stainless, bronze, colored sand, silica for sand casting, ceramic, and metal composites.
- Dimensionally accurate within 0.2mm for metal and 0.3mm for sand.
- Useful applications in metal part manufacturing, full-color products, and sand casting.
- Pros include affordability, large volume production, metal tool and components, any color reproductions, design versatility, and speed.
- Not as ideal as metal powder bed fusion for certain mechanical products.
Sand Binder Jetting
Sand binder jetting is a cheaper 3D printing method that creates parts from sand, sandstone, or gypsum. Sand binder jetting helps create high-value or individual pieces and tooling.
When the binder jetting process is complete, the molds are ready for casting once any loose sand (or powder component is used and removed). Extracting the final product requires breaking the mold.
Binder and sand binder jetting are ideal for producing complicated geometric designs at a low cost. This process is also highly adaptable to work within other manufacturing procedures.
Binder jetting is ideal for the fabrication of metal products. For this method, manufacturers use metal powder with a polymer binding component.
Plastic Binder Jetting (PJB)
PJB is the same process as metal binder jetting; only the substances used in the process differ. In this process, plastic powder and a liquid binder perform the task of creating an object. The machine for metal binding is also different.
Most printed parts in this process are ready for use but can be further developed by infilling, curing, polishing, or painting. They don’t require furnace sintering like metal and are advantageous over injection molding and other polymer 3D printer types.
Direct Energy Deposition (DED)
Thermal energy is a critical component in DED 3D printing. The material is fed, fused with powerful energy sources, and deposited simultaneously during the process.
This technology captures the power of an electron beam or laser. The heat source melts the material of choice, allowing it to create complex designs. DED is highly productive in the repair industry.
The powder is paired and sprayed with an inert gas to help with oxidation. This application can use mixed substances. The downside to DED printing is that there is considerable waste and post-processing work.
DED at a Glance
- Relies on substances available in wire or powder format.
- Dimensionally accurate within 0.1 mm.
- Preferred application for repairing automotive or aerospace, usable prototypes, and finished parts.
- Pros include workability in 3D, mixed metals, and no support structures.
- Negatives are the high cost, poor finish, and post-process work.
Electron Beam Additive Manufacturing (EBAM)
EBAM uses powder or wire feeds activated by an electron beam as the energy source. EBAM applications often happen in a vacuum to reduce contamination. Like other 3D printer types, the process layers the final object while the electronic beam deposits material activated in the program.
EBAM is an ideal process for medical implants or parts made from titanium, copper, cobalt, nickel alloys, pure titanium, or tantalum parts.
Laser Engineered Net Shaping (LENS)
LENS 3D printer types apply a unique method of combining a hermetic chamber and one or more nozzles that fuse a metal power with a powerful laser. The nozzle and laser project the material onto the platform and build the object.
Post-production is usually required.
Cold spray is a DED method that applies metal powders at supersonic speeds. It’s perfect for additive manufacturing in geometric designs.
Using cold spray negates the use of inert gas or a vacuum tank. Products usually undergo a finishing process with CNC equipment.
Related DED 3D Printing Types
- Direct Metal Deposition (DMD)
- Wire Arc Additive Manufacturing (WAAM)
- Rapid Plasma Deposition (RPD)
DMG Mori’s Lasertec 65 hybrid uses DED technology and CNC milling.
Micro 3D Printing
Micro 3D printing uses advanced technology to produce parts on a single-digit measurement. This technology makes items in nanometers (nm) with a layer width of 5 microns and a 2-micron resolution. Human DNA is 2.5 nanometers by comparison.
Micro 3D printing employs the technology of resin printers or photopolymerization. Advanced technology introduced various metal components with great success.
Micro 3D Printing at a Glance
- Ideal for use with metal, polymer, ceramic, copper, and gold.
- Dimensionally accurate to within: 30 µm.
- Used for medical implants, microneedle patches, and circuits.
- Proponents include strong micro parts and are cost-effective.
- Negatives include the initial expense of materials and printers.
Many 3D printer types overlap with other 3D print methods, and µSLA falls into the vat polymerization category. Companies using this tech expose photosensitive liquid resins to an ultraviolet laser. While the technique is similar to other resin printers, the state-of-the-art lasers and advanced lenses make it different.
Projection Microstereolithography (PµSL)
PµSL is becoming a popular additive manufacturing method. It’s inexpensive, accurate, fast, and versatile. Its versatility makes it ideal to use with polymers, ceramics, and bio-content, and positive results in tissue engineering and micro-optics.
This method relies on projecting ultraviolet light to produce liquid layers faster.
Two-Photon Polymerization (2PP or TPP)
Advances in 3D printer types have propelled 2PP into an exciting innovation for medical applications like tissue engineering, implants, and micromechanics.
Although this technology is slow and costly, achieving resolutions smaller than 1µm makes this an exciting entry into nanofabrication industries.
Lithography-based Metal Manufacturing (LMM)
LMM is another 3D printer type making inroads into surgical implements and micromechanical applications. LMM uses the same tech as photopolymerization, and feedstocks of titanium, tungsten, copper, silver, gold, and stainless steel are common and advantageous to this industry.
Sheet lamination stacks and laminates thin layers into a finished 3D item. Layers of material undergo either a heat or sound method to create the desired effect. It’s common in the production of paper, metals, or polymers.
This 3D printer type requires post-finishing and produces more waste. Sheet lamination is an inexpensive way to make composite and non-functional prototypes.
Sheet Lamination at a Glance
- Designed for use with polymer, paper, and metal sheets
- Dimensionally Accurate to within: 0.1 mm
- Use for non-functional prototypes, colored prints, and casting
- Pros include an inexpensive production
- Downside lies inaccurate products, waste; post-finishing
Laminated Object Manufacturing (LOM)
LOM is a popular sheet lamination method using glue. However, LOM is somewhat restricted and is unable to produce intricate shapes. Instead, a cutting device like a knife, router, or laser shapes the desired outcome.
LOM is a fast and efficiently inexpensive application to create even larger products that require post-finishing and create more waste.
Ultrasonic Consolidation (UC)
UC is also called ultrasonic additive manufacturing (UAM) and is ideal for producing a range of metal objects.
Pressure and ultrasonic vibrations bond thin metal sheets at a low temperature. UC allows manufacturers to join different metals in one process. A cutting machine like a CNC router cuts the final shape and post-finishing and waste are minor downsides.
Related Sheet Lamination Technologies
Other sheet lamination branches to fine-tune its applications for highly defined industries have a place in 3D printer type applications.
- Selective Lamination Composite Object Manufacturing (SLCOM)
- Plastic Sheet Lamination (PSL)
- Computer-Aided Manufacturing of Laminated Engineering Materials (CAM-LEM)
- Selective Deposition Lamination (SDL)
- Composite Based Additive Manufacturing (CBAM)
The technology behind 3D printer types is always growing. New frontiers have promising applications in all aspects of the industry with government support.