Stereolithography often uses a resin bath. A laser is used to selectively harden the layers to create the finished product. In most situations, a build plate is used in this process. Compared to FDM, it is inverted. The build plate is immersed in a resin bath from above, and the product is printed in an upside-down position.
The main advantage of SLA is the significantly higher resolution and quality of part processing. This is ensured by high durability and strength. Along with other important factors, this affects the development of models for SLA 3D printing.
Drainage
In the FDM process, the material is selectively extruded, while the SLA process selectively cures the photopolymer resin. This allows you to print parts that are hollow or partially hollow. This process must be performed correctly, otherwise the model will be filled with resin.
The method of creating a hollow model using drainage holes has gained wide popularity. Here you need to make enough holes to allow the resin to drain. This will not spoil the final appearance of the model.
Surface area and supports
During SLA printing, freshly cured layers are continuously separated from the film at the base of the resin bath. This can put significant pressure on the print. As a result, the product can be destroyed due to delamination, which is associated with the print coming off the build plate.
If you want to avoid this problem, you should make sure that the impression is characterized by its wide base. This approach will increase the surface area that rests on the build plate. This additional grip will provide protection against delamination.
If this is not possible, you can use supports. They also help with overhanging parts. In this situation, design will be important because you need to make sure that the support will work.
Detailing and deformation
If you compare SLA and FDM, you can get detailed models. They will be more fragile, and printing will take longer, but the result is increased accuracy and resolution. Therefore, designers can use options that are not available when working with FDM. These include interlocking parts, carvings, small holes, fine details, and complex textures.
Trapped and residual resin
Resin can become trapped in crevices and small corners of the product. If you don’t clean out the locking joints and small crevices before the curing process, the resin hardens. This leads to various problems, such as freezing of the joint in place.
To solve this problem, you need to avoid interlacing parts completely. Some components should be printed separately and then assembled. If this is undesirable or impossible, an alternative solution is to provide access for resin to drain from these areas. It is also possible to make a gap for drying and cleaning the affected parts before curing.
Material
In contrast to FDM, there is less choice of resin in SLA printing. Despite this, you can find materials that have improved parameters, such as cast or strong resin. If you are going to use this material, you should consider what characteristics it can provide.