Stereolithography is one of the most accurate among 3D printing processes, produces fine detail and smote surface often needing no further finishing. SLA is perfect for really small parts where FDM cannot produce a great details, but there are no technical limitations and machines capable of producing huge SLA parts also exist.
Like the other 3D printing techniques, the process begins with slicing the CAD model into thin layers, ready to be sent to the machine. SLA machines usually work with a vat full of liquid resin and a building platform moving in vertical direction. The machine starts building the model one layer at a time by curing the liquid resin with highly accurate UV light or laser. Once the layer is done, the build platform is lowered (or raised depending on the design of the machine) and a thin coat of fresh resin is spread on the object, allowing new layer to be accurately built on top. The laser continually traces and forms each layer until the part is ready – then it is carefully removed from the build platform. Depending on the machine and the type of resin a chemical or water bath is used to remove the excess resin and if needed the part is cured in UV oven, but it may also be ready to used. Support structures are used where needed to support overhangs, which won’t be possible to be printed otherwise. Here is the usual surface finish you can expect from this technology:
Different variations of the SLA process exist like patented PolyJet and ProJet, which are similar, but various may be used. Some of these machines can also print combination of different different materials in one part – rubber-like, transparent, multi-color, etc. Layer thickness is extremely low – from 0.02mm giving perfect surface quality and razor sharp precision. Build size varies depending on the machine and can be very low (jewlery machines for ex.), but may also be extremely large.
SLA parts are with very high resolution and quality and therefore need very little or no finishing at all afterwards. They can be sanded or painted if required. Please see our Finishing section for more information of the process and the service we provide.
SLA is suitable for the following applications:
- Concept modeling – very fine detail, accuracy and surface finish great proof of concept and design
- Functional prototypes – plastic models are tough enough for functional tests and variety of materials are available
- Marketing – perfect for design verification and great for marketing materials
- End-user parts – fast low volume production of customized parts, without tooling expense and lead time
- Manufacturing tools – quickly get hands on tooling masters, low volume tools
SLA is used in the following industries:
- Architecture modeling
SLA parts are good for the following post processing:
- Vacuum metalization