13.3.5 3D Printers

Learn about three-dimensional printers.

3D printing isn't a traditional printing method but is considered a manufacturing method. 3D printers are used to fabricate countless objects, from figurines to large concrete office buildings, along with food, clothing, jewelry, and art among many others. Scientists and engineers are finding new applications for 3D printing today.

3D Printing Technology

To print a 3D object, material is put down layer by layer and fused together to build a physical, three-dimensional object. The printer is controlled by a computer-based design file (a.k.a. CAD file) to reach extremely high precision and accuracy. This makes 3D printers capable of producing objects with highly complex shapes and structures, sometimes with internal trusses to reduce weight that would otherwise be impossible to build by hand.

However, there is no plug-and-play standard for 3D printing technology. Different researchers and engineers have built their own standards and designs from the ground up to meet their specific needs. There are many different 3D printer models that are designed to use different types of materials to build different objects.

A notable thing to know is that the largest 3D printer out there can print an entire house in a single day using efficient, safe, and sustainable construction practices.

Additive vs. Subtractive Manufacturing

Additive manufacturing is the process of building an object by applying material layer by layer and fusing them together, while subtractive manufacturing is the process of taking a hunk of material and cutting, grinding, drilling, or otherwise shaping the material until it results in the object desired. 3D printing is synonymous with additive manufacturing since it wastes little material along with the added bonus of being able to produce detailed, intricate objects that are fully functional without needed further assembly.

Printing Materials

Metals: stainless steel, solder, aluminum, titanium Plastics & Polymers: wood, ceramic, glass, plaster, filament Food: cheese, icing, chocolate (???) Bioinks: PEEK (used to bioprint human organ scaffolds in which human cells are transported into)

Fused Deposition Modeling (FDM)

Also known as fused filament fabrication (FFF). The most common and best-known 3D printing process. Filament is threaded to a printhead and through a single nozzle (similar to a hot-glue gun) that heats, melts, and then extrudes the filament to put down layer after layer of an object. Sometimes a printhead will have two nozzles to simultaneously build a support scaffolding for the object as needed, which is removed by the user once the print job is complete.

Stereolithography (SLA)

Uses a vat of resin and a laser to build objects. A UV laser is shined to the surface of the resin vat, drawing the shape of the pattern of the object onto it. When the laser hits the resin, the resin hardens. Using an elevator, the print bed is slightly lowered into the vat while a blade recoats the top of the vat with resin. Then the laser solidifies the next layer of the object, repeating the process until the object is fully built. When the print job is finished, the printed object must be washed with a special solvent to clean off unsolidified, non photopolymerized resin.

Bioprinting

The extension of 3D printing into the medical field is called bioprinting. Researchers in the bioprinting field are trying to create:

• artificial human skin for grafting and cancer research
• artificial air sac to serve as a replacement for human lungs
• artificial heart that'll serve as a replacement for human hearts
• capillary blood cell networks that can mimic the human body
• the scaffolding for the human bladder (success for 10+ years)

The Print Bed

The first layer of material laid down on the print bed is the foundation of your printed object, making maintenance of the print-bed crucial. The print bed is responsible for making the object securely stick to the surface to reduce warping and distortion during the print job. While there are a variety of additional adhesion methods, but they all depend on the type of material you're using, the type of surface your print bed is, and what you're going to print.

Surface Materials

• aluminum
• glass
• acrylic

Heated Print Beds

Heated print beds are used to help control the cooling process and to prevent poor adhesion to the bed, between layers, and warping from uneven or early cooling. It also reduces the chance of needing a do-over, which saves money in the long run.

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