By Olivia Cahoon
Three-dimensional (3D) printers are used in manufacturing settings to create prototypes, accelerate product development, and produce low-volume runs. Multiple methods of 3D printing exist, so manufacturers must decide which method best fits their needs.
Analyst firm, Gartner, identifies seven types of 3D printing technologies. Of these, two are comparable to print technology—binder and material jetting. Within these two types of 3D printing methods are various subcategories developed by 3D printer manufacturers using materials like acrylic, gel, metal, plaster, polymers, powder, and UV lighting.
Above: Proto Labs of Maple Plain, MN uses an HP Multi Jet Fusion using an HP Jet Fusion 3D 4200 3D printers to create custom prototypes for customers in the aerospace, automotive, consumer electronics, medical, and industrial machinery industries.
Binder jetting is an additive manufacturing 3D printing method that was developed in 1995 at MIT. It is also known as inkjet 3D printing or powder bed printing for its use of powder layers that bind to create an object.
The binder jetting process is similar to inkjet printing because it relies on printheads. 3D printers with binder jetting technology first distribute a layer of powder onto a build platform. The printheads then apply a liquid bonding agent, also known as a binder, which bonds the binder and powder together. The build platform is then lowered, and the next layer of powder and binder is repeatedly added until the object is complete.
Binder jetting allows for full-color printing by adding pigments, generally CMYK and white, to the binder. Because of its full-color capabilities, binder jetting technology is often used for rapid prototyping designs. In addition to color, parts can be made with a range of materials like acrylic powder, ceramics, metal, plaster, polymers, and sugar. “The inkjet component is the binder that holds the powder together and the color component for the outside of the print,” says Josh Hope, 3D printing and engineering products, Mimaki USA, Inc.
Using two materials, binder and powder, this 3D method allows for numerous combinations and various object properties like elastic, porous, smooth, rigid, and rough. It can be used for architectural construction, sculptures, statues, and short-run manufacturing in aerospace, automotive, and medical industries.
This technology is fast and inexpensive compared to other 3D printing processes. However, because a binder and powder are used, it generally produces fragile parts with limited mechanical properties unless additional post processing is applied, which prolongs the process. Additional mechanical properties include adhesives, epoxy, and melted wax. “Binder jetting prints are less expensive to produce but are more limited in resolution and are more fragile,” adds Hope.
Multi Jet Fusion
HP, Inc.’s Multi Jet Fusion is a sub-category of binder jetting that uses an inkjet array to selectively apply fusing and detailing agents across a bed of nylon powder. The powder and agents are fused by heating elements into a solid, which build upon layers to create a completed 3D part. “The process utilizes an engineering-grade nylon 12 powder, so parts are durable and suitable for functional testing and end use,” explains Ramon Pastor, VP/GM, HP Multi Jet Fusion, HP.
The process uses dual carriages that scan across the work area in perpendicular directions. As one carriage recoats the working area with fresh material, the other prints HP functional agents and fuses the printed areas. Pastor says this separates the processes of recoating and printing/fusing to optimize for performance, reliability, and productivity.
HP Multi Jet Fusion is used for short-run production, prototyping, and manufacturing production quality parts. Service bureaus and manufacturers can use this technology for parts traditionally produced with injection molding and CNC machining.
Released in November 2016, the HP Jet Fusion 3D 4200 uses HP Multi Jet Fusion for 3D printing. It produces at speeds of up to 42.29 square inches per hour with layer thicknesses from 0.07 to 0.12 millimeters. According to Pastor, by jetting HP functional agents using HP printheads, materials in the working area can be detailed, fused, and transformed point by point.
It uses thermoplastics including HP 3D High Reusability PA 12—a multipurpose thermoplastic. “HP 3D High Reusability PA 12 is ideal for making parts with complex surfaces and internal shapes for housings, panels, enclosures, and connectors,” shares Pastor. It also produces functional parts like gears, rotational joints, and sliders.
Similar to inkjet printing and binder jetting, material jetting uses photopolymers as a replacement for ink, which builds to form layers cured with UV light. Material jetting is an additive manufacturing process also known as drop on demand and wax casting.
Material jetting uses printheads that jet accurate droplets of melted wax materials onto a build platform. Once the materials cool they are solidified, which allows additional layers to build on top of each other. Material jetting machines vary in complexity and methods for controlling the material’s deposition. Once building is finished the material layers are cured and hardened using UV lights.
During this process, a different type of wax with a lower melting temperature acts as a support structure for overhangs. It allows complicated geometries to be successfully printed. Support materials can be removed by hand, in a heated bath, or with a high-powered water jet station.
Material jetting can use multiple print materials in one process. These devices are preferred for color, high accuracy, and smooth surface finishes. The ability to use multiple materials allows for the production of multi-color parts using CMYK and white. Textured layers can also be applied like brush strokes, gradient colors, patterns, and wood grain. Opaque, rigid, rubbery, and transparent materials can also be produced.
These types of characteristics enable dental, jewelry, and medical industries to adopt material jetting devices. For example, medical industries use this 3D process to create educational anatomical models.
However, because the material is deposited in drops, there is a limited number of materials that can be used including plastics, polymers, and waxes. 3D printed products produced with material jetting are unable to handle high temperatures and are generally fragile. This limits its use for products that require functional testing or real-world applications. Post-processing methods for material jetting include dying, metal plating, polishing, sanding, and support removal.
Hope believes the main difference between binder and material jetting is what material is used to build structures. “Typically, binder jetting prints are less expensive to produce but are more limited in resolution and more fragile. Material jetting prints are more expensive and more durable,” he continues.
The Mimaki 3DUJ-553 is a material jetting device, released in December 2017. It uses CMYK, white, and clear inks alongside support material. The device includes an ICC compliant workflow, 20x20x12-inch build area, 22 micron layer thickness, and water-soluble support material. According to Hope, it achieves over ten million colors.
MultiJet Printing is a type of material jetting that deposits plastic resin or casting wax materials by layers. 3D printers using this method use piezoelectric printhead technology for depositing consumables. The process uses thin layers of two UV-curable liquid waxes for building parts and support material. The support wax melts at a lower temperature and is post-processed with a no-touch method to prevent detail being lost during support removal.
MultiJet Printing builds molds, parts, and patterns with fine feature detail and layers as thin as 16 microns and resolution up to 1,200×1,200×1,600 dpi. These printers are typically office compatible and use standard electricity to create prototypes and indirect manufacturing aids. They are often used in aerospace, dental, jewelry, and medical applications because of the sharp-edge detail and high-resolution output.
3D Systems, Inc. released its MultiJet Printing 3D printer, ProJet MJP 2500W, in March 2017. It uses 100 percent RealWax VisiJet M2 CAST and eco-friendly, hands-free dissolvable wax VisiJet M2 SUW. The ProJet MJP 2500W prints 6.5 cubic inches per hour.
Jeff Blank, SVP, MultiJet Printing product development, 3D Systems, says the VisiJet M2 CAST wax material melts like standard casting waxes with negligible ash content in casting. “This wax material is durable for handling and casting fine features and the high contrast purple color allows for better detail visualization,” he offers.
The ProJet MJP 2500W is intended for intricate precision metal parts manufacturing with reduced metal hand polishing. According to Blank, casting foundries can eliminate tooling time, costs, and geometrics limitations while optimizing part and labor costs with the device.
Created by Stratasys Ltd., PolyJet Technology jets a liquid photopolymer solidified by UV light. This process is similar to material jetting and uses an additive manufacturing technique that builds upon layers until an entire part is formed. It also uses a removable gel-like support material where overhangs or complex shapes require support. Support material can be removed manually or with a water jet.
PolyJet Technology can jet layers as thin as 16 microns to produce fine details and smooth surfaces. Multiple materials and full CMYK colors are jet into a single print allowing for over 100 material combinations. It’s used to produce anatomical models, fixtures, form and fit models, jigs, molds, and presentation models.
The Stratasys J750, which uses PolyJet Technology, features full-color capability because it operates five different colors at once. Parts are produced in over 360,000 colors, textures, gradients, transparencies, and durometers. In September 2017, Stratasys introduced new material compatibility for the printer—Stratasys PolyJet Agilus30 rubber-like material and Digital ABS Plus engineering-grade material. Agilus30 is ideal for many prototyping requirements including advanced design verification and functional performance testing. Digital ABS Plus enables users to build strong functional prototypes, manufacturing tools, molds, snap-fit parts for high- or low-temperature use, electrical parts, and product casings.
Gel Dispensing Printing
Massivit 3D’s patented Gel Dispensing Printing (GDP) is a material jetting process that uses photosensitive gel dispensed onto a platform and cured with UV light. “GDP cures rapidly under UV light, enabling instant solidification of the printing material and consequently achieving very fast print speeds,” says Judith Vandsburger, director of sales, North America, Massivit.
Released in May 2016, the Massivit 1800 3D printer uses GDP with speeds up to 14 inches per hour and optional dual-object printing. The Massivit 1800 requires Dimengel, a proprietary photo polymeric acrylic gel. It’s compatible with a variety of coatings and finishes like epoxy, fiberglass, polyester, polyurethane, and self-adhesive vinyl.
According to Vandsburger, the printer utilizes techniques that allow it to print non-vertical walls and ceilings without the need to produce a solid object or intensive support structure. “These unique material properties mean the Massivit 1800 can produce impressive objects while reducing material costs, weight, and time,” she offers.
The Massivit 1800 produces hollow, lightweight products. It includes a touchscreen printer control and a vacuum print table with printing liner for object handling. The printer produces displays, life-sized statues, and prototypes.
For wide format print providers and sign businesses, Vandsburger believes the Massivit 1800 could potentially open the door for new business. “If you are running such a company, the Massivit 1800 will give you the ability to differentiate your offering and enhance your application gamut,” she explains.
Fused Deposition Modeling
Invented by Scott Crump, founder, Stratasys, Fused Deposition Modeling (FDM) is an additive manufacturing 3D printing process that builds layers by heating and extruding thermoplastic filament. It’s an office-friendly solution that supports production-grade thermoplastics and produces complex geometries and cavities.
Using FDM technology, the 3D printer heats plastic filament to a semi-liquid state and deposits it in ultra-fine beads along the extrusion path. If the 3D product requires support or buffering, the printer deposits a removable material that acts as scaffolding.
It uses materials like acrylonitrile butadiene styrene, polycarbonate, and Utem 9085 to create prototypes with chemical and thermal resistance. FDM is used in applications like carbon fiber layup tooling, fixtures, functional prototypes, jigs, low-volume production parts, and manufacturing aids. Medical industries use FDM for biocompatible and MRI transparent products while industrial settings with heavy equipment use it for strength and heat resistance. FDM is also used in aerospace applications for flame, smoke, and toxicity certifications.
According to Vandsburger, FDM technology produces lightweight, high-performance tools in less time and reduced costs, improving production line efficiency and accelerating time to market. “For low-volume production applications, FDM and its advanced materials offer manufacturers the ability to 3D print customized, durable production parts on demand—reducing the dependency on tooling,” she explains.
Compared to inkjet technology, Ben Malouf, director of marketing, Aleph Objects, Inc., says that FDM printers are much simpler. “In FDM, we are melting a thermoplastic filament and pushing the melted material through a nozzle. The result is generally a single-color object,” he offers.
Released in June 2017, Aleph Objects offers the LulzBot TAZ 6 that uses material extrusion FDM printing methods. It prints up to 200 millimeters per second and uses a three millimeter thermoplastic filament. According to Malouf, it features open source hardware, big build volume, a heated PEI build surface, and more than 30 support materials.
“With the ever-growing variety of materials that open filament format printers can utilize, and more advanced post-processing methods developing regularly, the use of FDM 3D printers in production is just starting to gain traction with manufacturers,” adds Malouf.
However, FDM printing has been criticized for its slow process and inability to produce parts strong enough for industrial applications. Michael Schuldt, COO, Stacker LLC, says slow speed can be addressed by using a 3D printer that incorporates multiple heads so users can effectively print faster by printing multiple copies of the same objects.
One such printer is the Stacker S4, released in August 2016. It requires a 1.75 millimeter diameter filament and has four printheads that can print up to four copies of the same object at once. It features a build volume of up to 14x20x25 inches and uses a variety of nozzle sizes for higher detailed prints or faster speeds.
Additionally, companies like Stacker are currently creating technologies to produce plastic parts with added durability. “In 2018, Stacker printers will begin to include FlashFuse technology by Essentium, which will revolutionize 3D printed parts because now we are actually producing plastic parts that are stronger than injected molded parts,” says Schuldt. Parts with added durability include annealed parts printed with annealable PLA like I-Beam IMPACT PLA.
The 3D Future
3D printing in the manufacturing space has a large growth opportunity. According to Pete Basiliere, research VP, imaging and printing services, Gartner, by 2020, 75 percent of manufacturing operations worldwide will be using 3D printed tools, jigs, and fixtures made in house or by a service bureau to produce finished goods.
“Beyond their use as production tools, 3D printers are invaluable for manufacturing jigs and product testing fixtures,” says Malouf. Prototyping is the first use for Aleph Objects’ 3D printers with jigs and fixtures coming in second.
Additionally, Malouf believes the growth for 3D printing in manufacturing settings is tremendous. In fact, he says Aleph Objects manufactures LulzBot desktop 3D printers using 3D printers to fabricate many of the parts. At its factory in CO, the company operates 155 LulzBot 3D printers 24/7 to keep up with printer production and have printed nearly two million production quality parts since 2011.
“We have customers doing the same thing, printing retail-ready components for off-road motorcycles, photography accessories, automated testing equipment, and electronics enclosures. 3D printers make the customization process so affordable, it’s crazy not to take advantage of it” says Malouf.
According to Pardon, the 3D printing market is projected to grow at a 30 percent compound annual growth rate over the next five years. “With that said, the big opportunity is addressing and transforming the $12 trillion manufacturing market,” he explains. “From design to workflow to materials to fabrication to post-processing to supply chain to recyclability, there is an opportunity to transform every step of the value chain.”
For a better outlook on how 3D printing will become the norm in production environments, manufacturers can look at the foundry industry, which has extensively incorporated 3D printing.
By using 3D printers, foundries receive design freedom, reduced labor, higher speeds, and the ability to create intricate features. “Just like my children cannot understand how a world without smartphones and the internet could have functioned, foundries who adopt 3D printing do everything with improved efficiency—once they move this direction, there is no reason to move backward,” shares Schuldt. The potential for 3D printers in manufacturing is so high that he believes it will likely be common in most industries over the next ten years.
Blank agrees and says there is a significant growth opportunity for 3D printing that enables real metal parts to be produced in a variety of alloys at lower part costs. For example, using a traditional wax injection tool to create an axial turbine blisk mold requires at least five weeks and may cost upwards of $20,000.
In comparison to traditional methods, Blank says the time and cost investments for 3D printed investment casting patterns is much lower. “A typical 3D Systems customer can create a 3D printed investment pattern overnight and in the morning it is ready for the foundry at a cost of under $2,000,” he points out.
3D printing methods like binder and material jetting are additive manufacturing processes comparable to inkjet printing technologies. FDM is another 3D printing method also commonly used in manufacturing. With a variety of consumables, these 3D printing processes aim to provide manufacturers with fast and cost-effective solutions for advancing productivity and providing full-color, intricate details. With reports of 3D printing expected to increase in manufacturing settings, opportunities for growth and automated manufacturing also increase.
Jan2018, Industrial Print Magazine