SLA(Stereo Lithography Apparatus

Technical principle:

The liquid tank is filled with liquid photosensitive resin, which will be quickly cured under the ultraviolet laser beam emitted by the laser (the laser used in SLA is different from the laser used in SLS, SLA uses ultraviolet laser, and SLS uses infrared laser). At the beginning of forming, the liftable worktable is below the liquid level, exactly one section thick. The laser beam focused by the lens scans the cross-sectional profile along the liquid surface in accordance with the machine instructions. The resin in the scanning area quickly solidifies, thereby completing the processing of a layer of cross section, and obtaining a layer of plastic sheet. Then, the workbench is lowered by the height of the layer thickness of one layer, and then the other layer is cured. Such layers are superimposed to construct a three-dimensional entity.

Advantages of SLA technology:

1) The development time is the longest, the technology is the most mature, and the application is the most extensive. Among the rapid prototyping machines installed around the world, light curing molding systems account for about 60%.

2) The forming speed is faster and the system works stably.

3) It is highly flexible.

4) The accuracy is very high, and it can reach the micron level, such as 0.025mm.

5) The surface quality is good and relatively smooth: suitable for fine parts.

Disadvantages of SLA technology:

1) Need to design support structure. The support structure needs to be removed when it is not fully cured, which is easy to damage the molded part.

2) The cost of equipment is high, and the cost of use and maintenance is not low. The SLA system requires precision equipment to operate liquids and has harsh requirements for the working environment.

3) The photosensitive resin is slightly toxic, pollutes the environment, and has allergic reactions to some human skins.

4) Resin materials are expensive, but the strength, stiffness, and heat resistance after molding are limited, which is not conducive to long-term storage.

5) Since the material is resin, it will melt if the temperature is too high, so the working temperature should not exceed 100℃. And after curing, it is brittle, easy to break, and the workability is not good. The molded parts are easy to absorb moisture and expand, and the corrosion resistance is not strong.