Professional metal 3D printers - Frequently asked questions - SISMA S.p.A.


During the printing process, is the material completely melted? Is any porosity present inside or on the surface?

The metal components printed with LMF (Laser Metal Fusion) technology generally have a rough surface but very high (close to 100%) densities, as the material is completely melted, not sintered.

What comes after the printing process?

The products manufactured with metal LMF technologies may be subjected to thermal treatment to relax any residual tension resulting from the process itself and to increase the mechanical properties (according to the material, various types of curing are possible, which may affect hardness, traction resistance and ductility).

The need to reduce surface roughness or satisfy very tight dimensional tolerance requires the use of different finishing technologies and surface re-finishing on the manufactured products. According to the material used, various kinds of machining technology (turning, milling), electrical discharge machining, polishing or electropolishing and surface coatings (PVD) may be used.

Can highly air-reactive materials be printed? What are the possible risks?

All materials are reactive to specific reagents, in various ways. That’s why the process inside the work chamber occurs always in the presence of an inert gas and the oxygen concentration is very low (under .3%).

In the event of highly reactive materials like aluminum and titanium alloys, the machines are fitted with oxygen level sensors that enable it to be reduced to under 100 parts per million (100ppm).

The risks related to the management of reactive materials are eliminated during the work process. To eliminate all hazards during equipment setups, the machines identified with the RM (reactive materials) mark have an opening with gloves that allow powder handling always in inert atmosphere, avoiding all contact between materials and the external environment.

Can precious and/or reflecting metals be printed? How can I minimize the use of these materials?

Precious metals are particularly reflective at typical infrared laser wavelengths of 1047 nm. Some MYSYNT100 machine setups, identified with the PM (precious metal) marking, use a laser spot with a reduced 30 µm diameter to increase the energy density at the same laser power.

These machines are also distinguished by a kit of interchangeable cylinders to change the work field from Ø100 mm to 63.5 mm and 34 mm