Today, 3D printing and additive manufacturing (AM) describe numerous individual processes, which vary in their method of layer manufacturing, material, and machine technology used.
SLA belongs to a family of additive manufacturing technologies known as vat photopolymerization. These machines are all built around the same principle, using a light source—UV laser or projector—to cure liquid resin into hardened plastic. The main physical differentiation lies in the arrangement of the core components, such as the light source, the build platform, and the resin tank.
SLA 3D printers provide the tool, but it’s the materials that empower stereolithography to create a wide range of functional parts for different industries. In this chapter, we’ll look into the photopolymerization process and its raw material, the resin, from its unique characteristics to the various compositions for specific applications.
the variety of resins come from Clear, Tough, Flexible and Castable resins.
HD Mechanical - spot S-Pro- SLA resin
investment castable resin(IC) - 3D Printing Materials for Jewelry
flexible sla resin - HD Elastic
Snow White Resin - HD white
durable tough resin - HD strong
The Polymerization Process
Plastics are made out of long carbon chains. The shorter the chain, the less solid or viscous the plastic. Resin is a plastic composed of short(er) carbon chains—from 1 carbon to a few thousand carbons. It has all of the components of the final plastic, but hasn’t been fully polymerized yet. When the resin is exposed to UV light, the chains join together to create much longer and therefore stiffer chains. When enough chains have reacted, the result is a solid part.
Once printing is completed, the parts remain on the build platform in the aforementioned green state. While they’ve reached their final shape and form, the polymerization reaction is not yet driven to completion, so mechanical and thermal properties are not fully set.
Stereolithography (SLA) applications
Stereolithography materials are generally formulated for specific applications or industries. Due to machine and process characteristics, proprietary materials tend to be limited to use in specific SLA systems.
customize 3d print object
3d printing engineering projects
Engineering resins simulate a range of injection-molded plastics, helping engineers and product designers conceptualize, prototype, test, and manufacture final products. With material characteristics like tough, durable, flexible, or temperature resistant these resins are used to create functional parts from assemblies to injection molds, soft-touch surfaces and consumer products.
3d printing dental
Dental materials allow dental labs and practices to create a range of personalised dental products in house. These parts are based on the patient’s scan intraoral, or CBCT scan, and designed for the treatment. Specific applications include orthodontic, diagnostic, and educational models as well as biocompatible parts like surgical and pilot drill guides.
3d printed Jewelry
SLA is ideal for prototyping and casting jewelry with intricate details. Standard modeling resins are recommended for prototyping to create an inexpensive “fitting ring” or “try on” piece to create excitement and deliver peace of mind to clients before casting. Castable resin is designed for direct investment casting, allowing jewelers and casting houses to go straight from digital design to a 3D print.
Costs and Value
Accurate prototypes, rapid iterations, and earlier discovery of errors all lead to better final results and less risk when moving from prototyping to production. In manufacturing, SLA reduces the need for expensive tooling, making small run or custom production—such as bridge manufacturing, custom jewelry, or personalised dental products—accessible.
Three common technologies for 3D printing plastics exist today. Fused deposition modeling (FDM) melts a string of thermoplastic filament and lays it down on a printbed, stereolithography (SLA) solidifies liquid photopolymer resin with a light source, and selective laser sintering (SLS) uses a laser to sinter powdered raw material.
Now that we understand the theory behind stereolithography, let’s explore what the printing process looks like on a desktop SLA printer.
This can be created using computer-aided design (CAD) software or developed from 3D scan data. The design is then exported as an .STL or .OBJ file that’s readable by the software that prepares the file for the 3D printer.
Each SLA printer includes software to specify printing settings and slice the digital model into layers for printing. Adjustable printing settings include orientation, support structures, layer height, and material. Once setup is complete, the software sends the instructions to the printer via a wireless or cable connection.
After a quick confirmation of the correct setup, the printing process begins and the machine can run unattended until the print is complete.
Once the print process is completed, the build platform can be removed from the printer. The printed parts then require rinsing in isopropyl alcohol (IPA) to remove any uncured resin from their surface.
Parts printed using functional resins require post-curing to finalize the polymerization process and stabilize mechanical properties.
After drying and curing, supports can be easily removed from the parts with flush cutters, and the remaining support marks sanded away for a clean finish.
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