1. Raw materials used and their characteristics
SLS prototype can use nylon powder, polycarbonate powder, acrylic polymer powder, polyethylene powder, nylon powder mixed with 50% glass beads, elastomer polymer powder, as well as ceramic or metal and binder powder and other materials, the performance is better; SLA prototype can only use liquid photosensitive polymer, and its performance is not as good as thermoplastic or thermosetting plastic.
2. Precision of prototype parts
The material shrinkage of SLA prototype is less than 0.4%, while that of SLS prototype is as high as 2% to 14%. Therefore, SLA can produce more elaborate workpieces.
3. Surface quality of prototype parts
During the sintering process of SLS, the temperature of powder material (or its binder) has just reached the melting point, so it can not flow well and fill the gap between powder particles. Therefore, the surface of the formed part is loose and rough, while that of SLA part is smooth.
4. Clarity of prototype feature structure
SLA is better than SLS in terms of the sharpness of the feature structure of the part. However, because of the need to make support structure in SLA forming, these support must be removed after forming, which will affect the sharpness of the contour edge.
5. Machinability of moulded parts
SLS and SLA prototype parts can be machined. However, most technicians believe that the thermoplastic materials used in SLS are better processed and can be easily milling, drilling and tapping. However, SLA parts should be processed carefully to prevent workpiece fragmentation.
6.Resistance of prototype to environment
The resistance of SLS prototype to environment (temperature, humidity and chemical corrosion) is similar to that of thermoplastic materials, while the resistance of SLA prototype is relatively poor. For example, SLA workpieces formed with epoxy resin are easily eroded by moisture and chemicals, and will soften and warp in the environment above 38 degrees.
7. Dimensional plasticity
When the required size of the prototype is too large, the three-dimensional model can be divided into several blocks, respectively, to be shaped, and then they are bonded into a whole. However, the bonding strength of SLS parts is better than that of SLA parts, because there are many holes on the surface of SLS parts, which is conducive to the penetration of viscose.
Generally speaking, SLA prototype has a fairly smooth surface and high dimensional accuracy, so it has a good observability. However, the SLS prototype has good strength and is not easily damaged when it is presented to users.
9. Supporting structure for prototype fabrication
As mentioned above, special support structures must be designed and manufactured in SLA moulding, while powder around the parts constitutes support during SLS moulding, so no special support structure is needed, which not only simplifies the design and manufacturing process, but also does not affect the surface quality of the parts due to the need to remove the support structure.
10. Performance for Detection
For shape, size and assembly testing, SLA parts have better performance; however, for function testing, SLS parts have better performance because the workpiece must bear a certain mechanical or thermal load, or must be placed in a humid, chemical corrosion environment.
11. Used as a replication prototype matrix
Rapid prototyping parts can usually be used as matrix to copy silicone rubber mold, epoxy resin mold or gypsum mold. SLA moulding parts are suitable for replicating prototype matrix because of their smooth surface, better dimensional accuracy and fine characteristics.
12. The Performance of Dies Made DirectlySLS can sinter ceramics or mixed powder of metal and binder, and then obtain ceramic or metal mould by subsequent treatment; SLA can be used to form die for wax loss casting, but it is difficult to directly make other die with higher requirements.