Resin 3d Printing, a sophisticated additive manufacturing technique, employs light to transform liquid resin into solid three-dimensional objects. This process, at its core, involves using a light source to selectively cure a vat of liquid resin, solidifying it layer by layer based on a digital design. Initially, traditional Stereolithography (SLA) 3D printers positioned the light source above the resin vat. However, the advent of inverted stereolithography revolutionized the field. Pioneered by Formlabs’ founders in 2011, this inverted approach places the light source beneath the resin vat. Here, each cross-sectional layer is traced onto the bottom of the resin, with the build platform ascending to allow fresh liquid resin to flow beneath the newly formed layer.
The development of inverted stereolithography was significantly propelled by innovations like the transparent and flexible bottomed resin tank. This novel tank design was crucial in enabling the creation of larger inverted SLA 3D printers by effectively minimizing peel forces through the flexible surface.
Resin 3D printers harness the power of light to cure light-sensitive thermoset materials known as “resin.” When these specialized resins are exposed to specific wavelengths of light, a fascinating chemical reaction occurs. Short molecular chains within the resin link together, a process called polymerization. This process converts monomers and oligomers into solid structures, forming rigid or flexible geometries as dictated by the 3D design.
Over the past decade, the landscape of resin 3D printing has expanded considerably. Several distinct resin 3D printing processes have emerged, primarily differentiated by their light sources. These variations include:
- Stereolithography (SLA): Utilizing lasers as the light source for precise curing.
- Digital Light Processing (DLP): Employing projectors to cast images and cure entire layers at once.
- Masked Stereolithography (MSLA) / LCD 3D Printing: Using LCD screens to selectively mask light and cure specific areas, often used interchangeably with LCD 3D printing due to the technology’s reliance on LCD panels.
Regardless of the light source’s orientation or type, the fundamental workflow of resin 3D printing remains consistent. After the printing phase is complete, a crucial washing step using alcohol or ether is necessary. This step removes any uncured liquid resin from the surface of the printed part, ensuring a clean and refined finish. Furthermore, depending on the specific resin material used, a post-curing process might be required. Post-curing fully completes the polymerization of the material, optimizing its mechanical properties and ensuring the part achieves its intended performance characteristics. For specialized applications or aesthetic enhancements, additional post-processing techniques such as coloring, coating, or plating can be applied to resin 3D printed parts.
