Additive Manufacturing and 3D Printing Lecture Notes

Flashcards covering the foundational families, processes, and design principles of additive manufacturing as discussed in the core lecture transcript.

Additive Manufacturing

The process of starting with nothing and building an object up layer by layer from a CAD digital file, as opposed to cutting material away.

Subtractive Manufacturing

The process where an object is created by starting with a larger piece of material and cutting away or shaping it to achieve the final part.

VAT photopolymerization

The first commercial 3D printing technology which uses a liquid polymer resin sensitive to UV light that hardens when selectively scanned by a laser or UV source.

Digital Light Projection (DLP)

A variation of VAT photopolymerization that is faster because it scans an entire two-dimensional plane of resin at once rather than using a single point laser.

Material Jetting

A technology that operates like an inkjet printer, jetting drops of liquid plastic or photosensitive polymers and instantly curing them with UV light.

Binder Jetting

A process that jets an adhesive or glue onto a bed of metal, polymer, or ceramic particles to bond them together without the use of heat during the initial printing stage.

Material Extrusion

A family of 3D printing, including basic filament-based printers, that works by pushing material through a moving nozzle to build parts.

Sheet Lamination

A 3D printing family involving the bonding or gluing of sheet materials, such as paper or metal foils, and cutting the outline for each layer.

Directed Energy Deposition (DED)

A technology that uses a heat source, such as a laser or electric arc, to create a melt pool while simultaneously injecting feedstock like powder or wire.

Powder Bed Fusion

A technology family where a heat source such as a laser or electron beam selectively fuses particles in a bed of powder layer by layer.

Sintering

The process of using heat to fuse individual powder particles together without fully melting them, often used as a post-processing step for binder jetting or in Selective Laser Sintering (SLS).

Selective Laser Melting (SLM)

A metal powder bed fusion process that uses high energy to fully melt powder particles into a single melt pool, providing better mechanical properties than sintering.

Residual Stresses

Internal stresses caused by the contraction and shrinking of metal during the cooling process, which can lead to warping or a "banana shape" in printed parts.

Support Material

Sacrificial structures designed to anchor a part to the build plate, remove heat from the melt pool reaching temperatures of higher than $2,000\,^{\circ}C$, and prevent sagging of overhangs.

Conformal Cooling Channels

Internal cooling passages in a mold that can only be produced via 3D printing to follow complex contours, reducing cycle times for injection molding parts.

Wire Arc Additive Manufacturing (WAM)

A form of DED that uses an electric arc on a robotic system to deposit wire feedstock, allowing for the creation of very large parts at a high deposition rate.

Hybrid Manufacturing

A machine system that combines the capabilities of additive manufacturing, specifically DED, with CNC machining in a single cell to allow for on-the-fly finishing.

Topology Optimization

A software-driven design methodology that uses generative design and simulations to determine where a part needs to be strong while removing unnecessary material.

Complexity is Free

A concept in 3D printing stating that intricate designs or internal structures do not increase the manufacturing cost and may actually reduce cost by using less material.

Martensite

A hard but brittle microstructure that can form in 3D printed metals like Ti-six-four due to extremely high cooling rates during the laser melting process.

Ti-six-four

The specific titanium alloy mentioned in the lecture used for high-performance parts like the bike handlebars and rocket nozzles.

Kartra

A company mentioned that produces pressure washers and utilized 3D printed molds with complex cooling channels to lower production cycle times from 22 seconds to 10 seconds.

MCORE Technologies

A company that produces a matrix unit 3D printer which uses regular office paper as input for cost-effective sheet lamination printing.