Additive technology is the manufacturing process of components and prototypes from a CAD model to its realization in 3D by adding layer upon layer of the desired material through a complex welding process. It can be understood as an opposite process to subtractive methodologies such as milling and turning, where you start from a metal block where material is removed mechanically, obtaining chips. This additive technology can be applied to both plastic and metallic materials. 3D printing is the effective operation, but Additive Manufacturing includes the entire production process. Additive manufacturing is associated to industrial applications such as production of functional prototypes or in specific cases series productions.
Additive manufacturing is used to produce both plastic and metal components. To realize these components there are various manufacturing technologies with different production techniques.
With regard to the fabrication of components in metal alloy, it is possible to identify the following technologies:
DMLS (direct metal laser sintering), SLM (selective laser melting) and EBM (electron beam melting).
- DMLS: a laser focused through special lenses melts a metal powder which then solidifies to form a layer of a few microns. The machine’s recoater then adds a new layer of atomized powder, repeating the process until the final component is made.
- SLM: This technology melts metal powders into a homogeneous mass rather than sintering them. The parts produced have the same characteristics and quality as other metal laser technologies.
- EBM: It allows to obtain metal parts by the generation of an electron beam instead of a laser. This technology allows to reach the same standards of the previous laser sintering technologies while maintaining the same excellent mechanical properties.
Technologies for plastic material
The fabrication of plastic parts in Additive Manufacturing is obtained by these main technologies:
Stereolithography (SLA), Fused Material Deposition Modeling (FDM), Selective Laser Sintering (SLS).
- SLA: it was the first additive technology to be introduced on the market. It is based on the polymerization of an epoxy resin that, due to the effect of a laser beam focused on the printing area through special optical systems, builds prototypes layer by layer.
- FDM: is a technology that uses a wire of polymeric material marketed in the form of a spool for the creation of components layer on layer. This technology requires the realization of the desired component through the use of two materials. One for the realization of the solid model, the other for the generation of support structures. The machines for this technology are equipped with two different heated extruders.
- SLS: This technology uses a laser to sinter and melt different powders of plastic materials such as polyamide (Nylon), thermoplastics and elastomers layer upon layer.
The advantages of additive manufacturing.
– Advantages of DMLS/SLM: the parts made with this technology have the same mechanical properties if not better than those made with traditional methods. High degrees of precision and detail are achieved. Prototypes and small series can be manufactured. Variety of materials can be used.
– Advantages of EBM: allows a slightly larger production compared to DMLS/SLM processes, but there are less defined details as regards the precision of surface finishes.
– Advantages of SLA: allows the production of pieces with complex geometries and with better surface finishes than the other additive processes; the objects produced are characterized by a high level of finish and an accurate definition of details, the result is optimal for verification tests.
– Advantages of FDM: reduction of lead time and costs, complex geometries can be realized, seamless components can be produced, variety of materials available.
– Advantages of SLS: plastic materials with superior characteristics can be used, resisting high mechanical stresses and high temperatures, compared to SLA technology. It is a precise technology for the realization of functional prototypes.
Most used materials in additive technology
With DMLS/SLM metal laser sintering technology, a wide variety of materials such as aluminum alloys, titanium, cobalt chrome, steel and nickel can be printed.
3D Metal specialized in making components from AISI 316L, a highly corrosion resistant austenitic alloy, Alsi10Mg, an aluminum based alloy with great machinability and fusibility.
Also used are special steels such as Maraging and Corrax with great characteristics. They are distinguished by their mechanical properties, high machinability, resistance to high temperatures, high hardness and low wear. In particular, Corrax has excellent stainless properties.
Fabrication of metal components in other material alloys are considered i.a.w. with the customer requirements, after the characterization of the material and testing of prototypes have been made.
3D Printing and Additive Technology
Conventional manufacturing technologies such as CNC machining are normally subtractive processes, which means they remove material to shape a product while metal 3D printing technology is an additive processes. One of the most common and popular metal 3D printing technologies is direct metal laser sintering (DMLS).
The typical DMLS process begins by splitting 3D design CAD file into extremely thin layers, effectively generating a 2D model for each layer.
The machine uses a high-power optical laser. Within the production chamber area, there is a material distribution platform and a production platform along with a roller used to distribute new powder onto the build platform. The technology dissolves the metal powder into a solid part by melting it locally through the laser beam equipped with focus. The parts are built additively layer by layer.
Why Choose 3D Metal?
It is possible to supply the finished component on a turn-key basis, following mechanical machining and appropriate dimensional testing.
During the design phase it is possible to optimize the component design by lightening it and proposing to the customer a newl solution for a number of mechanical assemblies.
The arrival of the supply can be guaranteed within 5 days from the confirmation of the order; in fact the production process is organized 24 hours a day increasing customer satisfaction.
The Company Additive technology is a completely green process: no material is wasted and no lubricants are used. Moreover, energy consumption is particularly low.
The gas used for the laser sintering process is nitrogen and makes up 70% of the air we breathe.