SLS to MJF comparison
The tenth chapter of the 3D printing guide is intended for those who want to produce a product from a thermoplastic polymer and want to decide between MJF and SLS technology.
Preface
MJF and SLS are technologies based on the melting of a powder substrate. In both processes 3D models are built layer by layer of polymer powder that undergoes sintering or melting.
The materials used in these prints are thermoplastic polymers (usually nylon) that come in powder form.
There are many similarities between the two printers and the quality of their products is similar. Nevertheless there are differences that need to be noticed and addressed according to the needs of the product.
The main difference between the two technologies is the melting or sintering factor.
SLS printers use a laser that sinks the powder in designated areas.
MJF printers use infra-red energy that melts the powder in designated areas.
An ink liquid called a fusing agent is applied to the powder in hardened areas. This liquid helps the powder absorb the infrared energy.
The differences are not limited to printing technology, there are other differences between the different types of printers that operate on the same technologies. Therefore the information given in this article mostly refers to the printing technology but there are exceptions depending on the specific printer.
Visibility differences
Because the MJF technology of HP 4200 machines uses fusing agent ink that is black during the printing process, the color of the products is gray. The parts can be painted by cooking them in color. The colored product is not glossy and the previous gray color can be seen through it. It is not possible to produce bright colors with cooking, but only with the help of exterior painting with the help of sample spraying.
Cooking in a different color from external spraying because it gives color to the whole part and not just to its outer shell. So even if the part is scratched, the interior of the product that will be exposed will be in the shade of the entire product.
In addition, the new HP printers allow you to print directly in color.
Conversely, since SLS technology does not use ink, the printed parts are white and can be cooked in bright and intense colors.
Mechanical differences
The mechanical aspects of the products vary according to the material from which the model is made. Usually the products of MJF technologies are more powerful than the products of SLS technology. In contrast, SLS products are somewhat more flexible than MJF products.
In addition, the minimum wall thickness that can be created in MJF technology is slightly lower than the thickness that can be produced in SLS technology. (MJF about 0.5mm and SLS about 0.7mm.)
