SLA parts are generally not suitable for the manufacture of functional parts subjected to loads (see rapid prototyping). The nature of stereolithography resins means that parts are brittle, less stable than other materials printed in 3D over long periods of time and undergo some creep. Most resin 3d printer parts require curing in a UV chamber after printing. Post-processing allows parts to reach the greatest possible resistance and become more stable.
Design for SLA printing
The level of detail that an SLA printer can produce depends on the size of the laser spot and the properties of the resin.
Stereolithography process resolution
SLA additive manufacturing can achieve much higher resolutions than FDM because it uses a laser to solidify the material. The high resolution of SLA printing in the XY direction (or horizontal resolution) depends on the size of the laser spot and can vary from 30 to 140 microns. This is not an adjustable print setting. The minimum size of the element cannot be less than the size of the laser dot.
The resolution in the Z direction (or vertical resolution) varies from 25 to 200 microns. The choice of vertical resolution is a compromise between speed and quality. For a part that has few curves or fine details, there will be little visual difference between printing at 25 microns and printing at 100 microns. By comparison, a desktop FDM 3D printer typically prints 150 to 400-micron layers on the Z axis.
Postprocessing in resin 3D printing via stereolithography
There is a whole range of surface finishes that can be achieved on parts printed with SLA technology. The desired surface condition often depends on the cost and the application.
Cost compared to the FDM process of additive manufacturing
The volume cost of the SLA resin compared to the filament used for the FDM printing is higher. As a result, SLA printing is generally more expensive, but SLA's ability to print complex details means it's a competitive option over many more industrial 3D printing technologies. A liter of standard SLA resin typically costs around $ 150 USD, while a 1 kg roll of ABS filament for FDM costs around US $ 25.
Each resin 3D printer is based on different types of materials: the deposition of molten material uses on the use of filaments, the stereolithography uses liquid resins (photopolymers). Finally, laser sintering requires thermoplastic powders, a material for additive manufacturing.