By Melissa Donovan
Part 1 of 2
Three-dimensional (3D) printing technologies are used in a number of industries. While much of what we hear about involves manufacturing in segments like automotive, aeronautics, and medical; there is a use for 3D printing beyond this. Print providers looking for unique ways to separate their business from the pack can complement their traditional two-dimensional (2D) print services by bringing 3D printing processes in house.
A 3D Overview
There are many organizations that classify the different types of 3D printing technologies. One to follow is the ASTM F2792 Standards Committee, which recognizes seven families of addictive manufacturing (AM) technology. These include binder jetting, directed energy deposition (DED), material extrusion, material jetting, powder bed fusion, sheet lamination, and vat photopolymerization.
Dr. Rashid Miraj, director of technical operations, AlphaSTAR Corporation, explains that in binder jetting, liquid bonding agents are applied on thin layers of powdered material, this builds up parts layer by layer. The binders include organic and inorganic materials. If the powdered material is metal or ceramic, the parts are commonly fired in a furnace after they are printed.
DED includes laser metal deposition, laser engineered net shaping, direct metal deposition, laser engineered net shaping, and direct metal deposition. During this process, “powder or wire is fed into a melt pool, which is generated on the surface of the part where it adheres to the underlying part or layers by using an energy source such as a laser or electron beam. This is essentially a form of automated build-up welding,” says Miraj.
In material extrusion, material is extruded through a nozzle or orifice in tracks or beads. These are then combined into multi-layer models, according to Miraj. He lists common varieties like heated thermoplastic extrusion—similar to a hot glue gun—and syringe dispensing.
Fused deposition modeling (FDM) and fused filament fabrication are examples of material extrusion. “FDM is what most people envision when they think of 3D printing. The material is some type of spooled plastic filament, which is heated to a melting point and then extruded out of a nozzle to build the model,” explains Josh Hope, senior manager, engineering projects, Mimaki USA, Inc.
Hope believes the 3D technology most relatable to 2D printing providers is material jetting, as it resembles traditional inkjet printing. In his experience, “liquid photopolymers are jetted from inkjet printheads and cured to a solid state with UV light—layer by layer—to build a final 3D model.”
Another example of material jetting is when jetting thermally molten materials that then solidify in ambient temperatures, adds Miraj.
Material jetting processes include Polyjet, smooth curvatures printing, multi-jet modeling, and Projet.
Powder Bed Fusion
During the powder bed fusion 3D printing process, powder material is consolidated by melting it together using a heat source such as a laser or electron beam. “The powder surrounding the consolidated part acts as a support material for overhanging features,” shares Miraj.
Examples of powder bed fusion include selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, selective heat sintering, and Multi-Jet Fusion.
In sheet lamination, materials are stacked and laminated together to form an object. Depending on the material the lamination method varies. Miraj explains that if paper or plastic an adhesive or chemical is used, for metals brazing is an option. Another lamination technique is ultrasonic welding.
Examples of sheet lamination are laminated object manufacture, selective deposition lamination, and ultrasonic AM.
Vat polymerization includes stereolithography apparatus (SLA); digital light processing; scan, spin, and selectively photocure; and continuous liquid interface production. “A vat of liquid photopolymer resin is cured through selective exposure to light—via a laser or projector—which then initiates polymerization and converts the exposed areas to a solid part,” says Miraj.
The Best Option
When it comes to selecting the best technology for a print provider, it is important to first identify what type of objects they plan on printing. Knowing this will narrow down considerations such as material type as well as building volume requirements.
For those in 2D printing, Brian Crotty, marketing team manager and PR, 3YOURMIND, suggests an easy entry point into 3D printing is digitally storing and producing spare parts and custom components to minimize downtime on existing production lines.
“These types of replacement parts have a low-entry barrier because they can often be produced on lower cost, prosumer machines. A single day of reduced downtime from producing a replacement part can often cover the initial investment in the machine,” he continues.
Hope recommends FDM or SLA if the company is looking to produce low-cost jigs or printing fixtures. For printing in full-color output, material jetting is preferred.
“The best recommendation would be to learn about the various technologies and select a technology that closely fits the print provider’s existing business practice as a first step,” adds Miraj.
Challenges to be Aware Of
While 3D printing is a hot topic of conversation, print providers need to be aware of the challenges associated with the process. Like any new application, there is a learning curve involved and in the case of 3D printing it is centered on designing the appropriate files.
Alex Monino, VP, global strategy, 3D printing and digital manufacturing, HP Inc., believes that in order for print providers to use 3D printing technologies effectively, they must learn how to design in 3D. “When implementing 3D printing you won’t truly unlock the benefits unless you start the design process with 3D at the forefront. By designing for 3D you are freed from traditional constraints. You can unlock all new possibilities that were never possible before. This makes parts and products lighter, cheaper, and faster than ever before.”
In many scenarios, the 3D file will look fine on screen, but lacks in structural soundness. Hope says there are many different software packages available—some free—that offer tools for both designing and troubleshooting 3D files prior to printing.
Directly related to this, a print provider may realize that the best course of action is to hire a trained print technician to design for 3D instead of learning on their own. “As any business operator understands there is a cost for tools and a cost for talent. In AM that talent may be a print technician, as well as a design engineer and a simulation analyst. In some cases, all skills could be folded into a single individual,” recommends Miraj.
For Crotty, the most significant barrier is in educating the current sales and production teams on how to sell and produce 3D printed parts. “While most print providers are adjusting output regularly, 3D printing still has significantly fewer units per order and significantly longer production times. This requires a shift in mindset and longer term planning to accommodate 3D printing into the production workflow.”
Closing In On 3D
3D printing is a growing market. Print providers should take the time to evaluate the various available technologies and whether one or more of them might be a step in the right direction for their business.
The next part in this series discusses the benefits of capitalizing on 3D printing and shares some of the 3D printers targeting print providers.
Apr2020, DPS Magazine