Types of resins - Microsoft Teams Tutorial

- [Instructor 1] Stereolithography or SLA 3D printers have fallen in price in the last several years. These machines use a UV light source to selectively solidify liquid photopolymer resins. A photopolymer turns from a liquid to a solid when it's exposed to the correct wavelength of light. Most modern resin printers print upside down, with a shallow resin vat that's illuminated from below. Resin printers can produce prints with incredibly fine detail, but require far more challenging materials management than do filament printers. Most SLA printers have small build areas compared to filament printers. There're even resin printers designed for nano-scale printing, using a process called 2-Photon Polymerization. These examples were created by UpNano, which you can read more about at upnano.at. In many ways, the applications now are driven by what types of resins are available. This movie will review some of the types of resin printers and printable resins. Many new resins are being developed all the time. Some resins are designed for particular 3D printers and some 3D printers will only use resins designed for them. Specifically, the type and concentration of photo initiator, which affects how UV light hardens the resin, will vary with different printing technologies. Most generic resins are formulated for the cheaper mSLA technique, which uses an LCD screen placed against the bottom of the vat. Higher-end printers that use DLP projection, or a laser galvanometer for illumination might work better with different amounts of photo initiator. Check that your printer can use the resin in question before you purchase it. Resin costs can vary as well as mechanical properties and the time needed to cure a part. - [Instructor 2] The first area the SLA prints stand out from other technologies is transparency. This has more to do with the smoother surfaces and non-porous nature of the print, rather than the availability of transparent materials. Still, after cleaning prints the surface will usually have a frosted appearance unless a clear coat or some other surface-smoothing procedure is used. There're also castable resins, which are formulated with wax like properties for use in investment casting. This allows them to be used as direct replacement in the lost-wax casting process that's been used by jewelry makers for thousands of years. Using resin prints instead of hand carved wax makes the process more repeatable and less labor intensive. As with the traditional process, the design is first created from a meltable material, and screws are added. They're then encased in a ceramic material and burned out to create a mold. Molten metal is poured in and the mold is destroyed to free the metal copy. Dental resins are another hot area for resin printing right now. Dentists are able to print a variety of molds and forms for things like implants, aligners, and surgical guides. Resins for prints that can actually be used inside the mouth are beginning to come out of the approval process. Resin printing is a chemical process rather than a thermal one, like most other printing techniques. This makes it possible to formulate resins that can withstand much higher temperatures. One exciting application is to significantly reduce the time and cost of producing tooling for short-run injection molding. Most standard resins produce brittle prints. High-impact resins are more able to withstand forces. There are now resins with various desirable properties, like durable and flexible resins. Some resins consist of a carrier and a filler, which we discuss in detail in another movie in this course. For example, ceramic resins are fired after printing and glass-filled resins offer increased rigidity. SLA is a single material, single color process. However, there are also printers that use inkjet print heads to deposit resin in tiny droplets. These resin jetting machines print with a second material for supports that can be dissolved or melted away. Some can even mix color resins for full color printing, or mix hard and flexible materials to produce a gradient of material properties. - [Instructor 1] Resin printing is advancing rapidly because of advances in the technologies of the printers, but also because the expanding range of materials that are available. Resin printers are likely to have proprietary hardware, software, and resins, all meant to work together. If you're buying a resin specifically to work in a particular material, be sure the combination works for your printer.