3D printing

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3D printing

The making of parts and products using a computer-driven, additive process, one layer at a time. 3D printing builds parts out of plastic, metal and other materials directly from CAD drawings that have been cross sectioned into thousands of layers. Sizes of printed objects run the gamut from approximately 16 to 4,000 cubic inches; however, Shanghai-based WinSun built huge machines to print house walls and trusses. See 3D printing materials.

Used for making prototypes as well as final products, 3D printing evolved from the "rapid prototyping" industry, pioneered by Chuck Hull of 3D Systems in the mid-1980s. It provides a faster and less costly alternative to machining (cutting, turning, grinding and drilling solid materials).

Concept, Prototype and Final Product
Capable of making a part from scratch in hours, or just minutes for small objects, 3D printing is used to create models to determine if a design meets customer expectations. 3D printing can more easily create prototypes of parts to test their form, fit and function with the rest of an assembly.

Tooling molds and dies, as well as patterns for castings, are 3D printed. Either the actual mold or the model to make the mold can be produced more quickly and economically than with conventional methods.

Laser sintering and electron beam melting technologies turned "rapid prototyping" into "rapid manufacturing," in which short runs of actual finished parts are made. These techniques have created breakthroughs in the medical industry, including products customized for humans such as hearing aids, dental crowns and medical implants. In 2019, Israeli scientists at Tel Aviv University 3D printed a heart with human tissue. Although only the size of a rabbit's heart, human hearts suitable for transplanting are hopeful in the years to come.

One Layer at a Time
All 3D printers are "additive fabrication" machines that build one layer after the other. The layers can be as thin as 1/1,000th of an inch or much thicker. The building material can be a liquid, powder or sheet material that is cured by heat, UV light, a chemical reaction or other method. The thickness exception is the cement mixture used by WinSun to print house walls in China. Following are the more common methods used to print 3D objects. See 3D printer, personal 3D printer, nanofactory and STL.


The Bible of 3D Printing
Known worldwide, Terry Wohlers' industry report describes the applications, players and technologies of 3D printing. For more information, visit www.wohlersassociates.com.







Stereolithography
In the mid-1980s, Chuck Hull pioneered the stereolithography apparatus (SLA) and ushered in rapid prototyping. Parts are built from a liquid photopolymer, and each layer is cured by a UV laser. When the excess resin and supports are removed, the whole part is cured. (Image courtesy of 3D Systems, Inc., www.3dsystems.com)







Laser Sintering
Laser sintering machines build parts from powdered plastics and metals that are heated by a laser. At the end of the job, the excess powder is removed and recycled for the next build. This metal part was created in a 3D Systems Sinterstation using the company's LaserForm resin. (Image courtesy of 3D Systems, Inc., www.3dsystems.com)







Fused Deposition Modeling (FDM)
FDM machines deposit a thermoplastic through a heated nozzle to form the layers, and the plastic solidifies. Developed by Scott Crump of Stratasys in the late 1980s, FDM is a popular technology for making prototypes. This is a close-up of the print head of a Stratasys FDM machine.







Electron Beam Melting (EBM)
Using an electron beam that melts metal powder a layer at a time in a vacuum chamber, EBM printers create titanium and cobalt chrome parts. Conventional machining may be required for finishing. These engine parts were made with an Arcam system. (Image courtesy of Arcam AB, www.arcam.com)







3D Printing in Colors
Z Corporation printers add color binders onto powdered, composite materials one layer at a time. This model was created as a single unit, and the excess powder was removed at the end. When any gear is rotated, all the others move. In 2011, the company was acquired by 3D Systems.







Jetting Liquid Polymer
Like inkjet printers, the Stratasys Objet piezoelectric print heads use thousands of nozzles to jet 16-micron layers of photopolymer that are immediately cured by UV light. The materials for the part and for the voids come from different nozzles. (Image courtesy of Stratasys Ltd., www.stratasys.com)







Medical Breakthroughs
By examining a plastic 3D model (top) derived from a CAT scan or MRI of the patient, surgeons can save hours at the operating table. 3D printers can also make custom parts like this cobalt chrome knee implant (bottom). (Images courtesy of Stratasys Ltd., www.stratasys.com and EOS GmbH, www.eos.info.)


Medical Breakthroughs
By examining a plastic 3D model (top) derived from a CAT scan or MRI of the patient, surgeons can save hours at the operating table. 3D printers can also make custom parts like this cobalt chrome knee implant (bottom). (Images courtesy of Stratasys Ltd., www.stratasys.com and EOS GmbH, www.eos.info.)
References in periodicals archive ?
For those who supply artificial limbs, 3-D printing offers a relatively easy way to make them.
He and his team develop those products using a tool that for many manufacturers is still relatively new: 3-D printing.
3-D printing or additive manufacturing is a process of making three dimensional solid objects from a digital file.
The newly formed ACI Committee 564, 3-D Printing with Cementitious Materials will report on three-dimensional printing and additive manufacturing with inorganic cementitious materials, and develop publications on the technology's applications, challenges and impacts.
Now, 3-D printing eliminates all that lost material for the domes, and the titanium used for printing is readily available with no wait time, the company stated.
Additive manufacturing uses 3-D printing software to break down a digital model into layers that can be reproduced by the printer, which then builds the model from the ground up, layer by layer, creating a tangible object.
The 3-D printing of cores and complete molds, without any requirement for tooling, is revolutionizing the industry of fast prototype casting manufacturing but it also offers distinct advantages for certain production castings.
Additive manufacturing (or 3-D printing) is different from subtractive manufacturing processes, which typically involve grinding, cutting, or milling, because 3-D printers function by building a part layer by layer, each as thin as 50 um.
3-D PRINTING HAS BEEN AROUND SINCE THE 1980S, BUT IT WASN'T UNTIL THE PAST FEW YEARS, when the price dropped below $5,000, that the technology became accessible to a much wider audience--including teachers and students.
Other Lake County libraries offering 3-D printing services to patrons include Ela Area Public Library in Lake Zurich, Fremont Public Library in Mundelein and Wauconda Area Library.
"The organ models we are 3-D printing are almost a perfect replica in terms of the look and feel of an individual's organ, using our custom-built 3-D printers," said lead researcher Michael McAlpine of the University of Minnesota's College of Science and Engineering.
Since the early 2010's, scientists across the world have been experimenting with the potential uses of 3-D printing technology, especially in medicine.