History and Technology of Stereolithography - SLA printing invented by Hideo Kodama in the early 1980s - French inventors filed a patent for stereolithography process - Chuck Hull coined the term 'stereolithography' and patented the process - Chuck Hull co-founded the first 3D printing company, 3D Systems - Stereolithography achieved industry status in the automotive industry - Stereolithography is an additive manufacturing process - UV laser is used to draw a pre-programmed design on the photopolymer vat - Photopolymer resin is solidified to form each layer of the 3D object - Build platform lowers one layer at a time, and a blade recoats the top of the tank - Completed parts need to be washed with a solvent to remove wet resin

Materials Used in Stereolithography - Resins are commonly used in SLA printing - Resins can have various properties, such as softness or hardness - Resins can be filled with secondary materials like glass or ceramic - Different resins are available for general prototyping, engineering, dental and medical applications, and casting - Biomaterial resins can be formulated with synthetic or biological polymers

Medical Applications of Stereolithography - Stereolithographic models used in medicine since the 1990s - Accurate 3D models created based on data from computer scans - CT, MRI, or other scans used to acquire data for modeling - Segmentation process used to isolate specific tissues or organs - Stereolithographic models used for diagnosis, pre-operative planning, and education in medicine

Advantages and Disadvantages of Stereolithography Advantages: - Fast manufacturing process, with functional parts produced within a day - Printing time depends on complexity and size of design, ranging from hours to more than a day - SLA printed parts have superior surface quality and no visible layering pattern - Prototypes and designs made with stereolithography are strong enough to be machined - Can be used to create master patterns for injection molding and metal casting processes

Disadvantages: - Often costly, although prices have been decreasing since 2012 - Introduction of consumer SLA machines has made it more affordable - Photopolymers used in SLA are sticky, messy, and require careful handling - Newly made parts need to be washed, further cured, and dried - Limited choice of materials compared to FFF/FDM

Other 3D Printing Methods - Fused filament fabrication (FFF or FDM) - Selective laser sintering (SLS) - Thermoforming - Laminated object manufacturing (LOM)