In this paper, the leading professional photopolymerization system manufacturer explains the the differences between SLA, DLP and 3SP for additive manufacturing in a large build envelope when high accuracy, repeatability, reliability and throughput are required.
Vat photopolymerization, in which a light source is used to selectively cure or harden photopolymer resins inside a vat or tray, has become a popular method of 3D printing among manufacturers for a variety of reasons. For example, the photopolymer resins used during this process are also known as thermosetting plastics or thermosets, which strengthen during post-curing and hold their shape, even after reheating. This is in contrast to thermoplastics, which can be re-melted after being formed into a part.
A wide range of thermoset materials are also available today with a variety of desirable properties, such as epoxies, which offer elasticity and exceptional chemical resistance, as well as biocompatible materials. The vat photopolymerization category includes stereolithography (SLA), digital light processing (DLP) and a new method launched in 2013 called 3SP for scan, spin and selectively photocure.
3SP specializes in affordably building accurate parts with a smooth surface finish across a relatively large build envelope, where traditional SLA and DLP have challenges scaling up in size affordably. This allows for 3D printing of a single large part or a tray of smaller parts. To understand why 3SP is so unique in its benefits, it’s critical to understand the limits of SLA and DLP.
Understanding the limits of projectors, the engineering team at EnvisionTEC started with the idea of a laser beam that, instead of being fixed as in most SLA systems, actually travels over the resin tray to reduce the need for a variety of expensive lasers, galvo mirrors and optics. The R&D team also wanted to draw out images in a more efficient manner. The patented 3SP machine design is unlike anything on the market, offering a simple and affordable solution for 3D printing quality parts on a large build tray.
You can download the full paper here.