Review of photopolymer materials in masked stereolithographic additive manufacturing

Abstract

Among the many types of additive manufacturing, stereolithography (SLA) stands out as one of the most versatile technologies, especially in the production of large prototypes of extremely high surface quality. The basic working principle of this technology has not changed for almost thirty years, but the recent rapid development of the mask-based variant of stereolithographic 3D printing technology (MSLA) has significantly increased its popularity and made it available to a wider range of users. This is especially true for MSLA 3D printers that use liquid crystal displays (LCD) for mask forming. These 3D printers are characterized by large build volume, high resolution and speed of model production, and low price. These factors make them extremely attractive for rapid prototyping or small-scale serial production. However, although they are superior to classical laser-based stereolithography in many technical aspects, their current main drawback is the smaller range of available materials. The development of modern stereolithographic technology has clearly shown that the capabilities of 3D printers themselves are just as important as the materials from which the models are made, the diversity of their mechanical characteristics, available colours, and optical properties. The materials used in all variants of SLA technology are liquid thermoset polymers that are sensitive to UV light (photopolymers). A wide range of areas of application requires a wide range of materials that meet the specific needs of each application. MSLA, as a newer technology, still does not have the same range of materials as 3D printers based on the laser variant of stereolithography. The situation is significantly improving with the increase in the number of available MSLA 3D printers, their popularity, and improved technical characteristics, and it can be said that this is the last step in legitimizing MSLA technology as a competitor to laser stereolithography. The aim of this paper is to analyse the material market for MSLA technology, categorize the supply of materials and objectively compare the available materials with those offered by reputable manufacturers of materials for classic SLA 3D laser printers. Special emphasis is placed on the quality and scope of technical specifications of MSLA materials, which is crucial for their professional use. In addition, the impact of thermoset polymers on user health and the environment is an especially important topic, so an overview of plant-based materials was also made.