Highly complex components which cannot be made by conventional methods can be produced tool-less by additive manufacturing, e.g. undercuttings and grid structures. The characteristic feature of these processes is the elemental or layered structure of the component.
Selective Laser Sintering (SLS) uses a laser which melts the polymer powder point to point. The device is built up by a layer by layer coating of thin powder layers on a powder platform following a laser induced fusing process. This procedure is repeated until a 3D device is produced. The unfused powder of each layer is used as support material and can be removed easily.
Selective Laser Sintering is a useful method for producing devices with a high mechanical load capacity and complex structures without using supports.
The HP Multi Jet Fusion (MJF) process uses infrared radiation for fusing the polymer powder layer by layer. The whole layer is irradiated by a planar infrared heater and not local with a laser point by point. For this reason, it is necessary to add infrared absorbing ink on the parts of the layer which shall be fused. An important advantage is that the building time doesn’t depends on the number of devices and the two-dimensional size (x,y). Only the height of the object (z) is important for the building time.
A “Processing Station”, which relates to the printing system, is used for the whole powder management, which includes removing the unfused powder and refilling the printing unit. The maximal amount on recycled powder (powder, which was used in the printing unit) can reach 85%. The conditioning of the powder works automatically with integrated filter systems. This ensures a nearly complete conversion of powder in devices.
The HP Multi Jet Fusion technology leads to lower costs and shorter building times compared to other powder-based applications. The devices have a high mechanical load capacity.
The ARBURG Plastics Freeforming (APF) is based on the extrusion of chains of polymer droplets. Characteristic for this application is the printing with standard granules, which are normally used in injection molding or extrusion processes. The granulate is plastified with an extrusion unit and the droplets are produced by using a piezo-electric nozzle-pin combination. The freeformer has a very high resolution by extruding a well-defined dose of droplets.
The usage of standard granules leads to a high variety of materials. The freeformer has two extrusion units which enables the producing of support structures or two component devices.
The Fused-Filament-Fabrication (FFF) uses polymer filaments as raw material. The filament is melted with an extrusion unit and each layer of the device is placed on the building platform by moving the extrusion unit. After placing a whole layer, the distance between the extrusion unit and the printing bed is increased about the layer thickness. This is repeated until the whole device is built up. With a dual extruder system (2 extrusion units) it is possible to produce devices consisting of different materials or built complex structures with a water soluble support structure.
Fused Deposition Modeling (FDM) uses metal filaments as the starting materials. So far, only weldable alloys can be additively manufactured with this process.
The filament is drawn into a heated extruder nozzle and melted. By moving the nozzle in Z- and X-directions, a three dimensional component is built up from the molten material layer by layer. A subsequent debinding process removes the organic material from the printed component. Finally, the sintering process is carried out to ensure low porosity. This process is suitable to produce medium-sized and complex metallic components. Especially, non-weldable alloys could be manufactured with this process.
NMB is currently researching the printability of non-weldable high temperature alloys such as nickel alloys, which are used in engine and turbine construction. Highly filled filaments with a metal weight percentage of at least 90 % can be used for this purpose.
Wire-based laser deposition welding offers an economical process alternative to powder-additive production, since cheaper metal wires are used for layer build-up. NMB has a laser deposition welding system that enables significant process improvements. For this purpose, the prototype system was equipped with two additional components. A device for preheating the wire means that less laser power is required during the subsequent melting process. Another advantage of this preheating is that thicker wires are melted at lower laser power, which creates the conditions for higher build-up rates. Hybrid components manufactured by additive and subtractive manufacturing can be assembled on the system. A combination of different additive processes is also possible.
This process enables the production of large and complex lightweight structures from high-strength alloys using high vacuum ≤ 5 x 10-5 mbar.
The machine was developed within the cooperation project "Process and plant prototype for additive series production of large and complex lightweight structures from high-strength alloys (AdLes)" together with the project partners Evobeam GmbH (evobeam) IRCAM GmbH (IRCAM), Universität Bremen, Airbus Stiftungsprofessur für Integrative Simulation und Engineering von Materialien und Prozessen.
The ZIM-Koop project ZF 4176702LP6 was funded by AiF Projekt GmbH within the Central Innovation Program for Small and Medium-Sized Enterprises (ZIM) of the Federal Ministry of Economics and Technology on the basis of a resolution of the German Bundestag.
We work with selective laser melting on a Mlab-system from the manufacturer CONCEPT Laser. Here, components can be manufactured from a wide range of metal alloys as part of a contract manufacturing process. Fine metal powder is locally melted by a high-energy fiber laser. After cooling, the material solidifies. The component is built up layer by layer by lowering the floor of the installation space, applying new powder and melting again.
This process is used for development work and for the contract manufacture of prototypes, pilot series and small series.
Tools with a close-contour temperature control system are often additive manufactured - but with conventional processes this is a lengthy and expensive process. We offer the possibility to develop and produce 3D tools with contoured temperature control channels by means of diffusion bonding. This process enables the production of complex and large tools at high speed compared to conventional machining and additive manufacturing methods.
Diffusion bonding is based on the use of commercially available cut sheet metal. These sheets are joined either with a brazing alloy (diffusion brazing) or only with press force (diffusion welding).
Selective Laser Melting (SLM) is a process for the layer-by-layer construction of complex structures and is currently one of the most innovative processes on the market. In this process, a powdered raw material is applied to a carrier plate and, depending on the desired geometry of the workpiece to be produced, is selectively welded to the previous layers using a laser beam. This procedure is repeated layer by layer until the finished component is available at the end. The achievable component properties and component quality are primarily dependent on the stability of the melting process. When processing reactive materials this machine enables a process carried out under to protect molten metal from oxidation by atmospheric oxygen.
This process enables us to obtain low-stress and low-warpage elements from complex components of various alloys with a very low proportion of microdefects.
The machine was developed within the cooperation project "New process for generative layer production by selective laser melting under vacuum (SLaVa)" together with the project partners evobeam GmbH, Bach Resistor Ceramics GmbH and Airbus Endowed Chair for Integrative Simulation and Engineering of Materials and Processes.
The ZIM-Koop project KF2481016CK4 was funded by AiF Projekt GmbH within the Central Innovation Program for Small and Medium-Sized Enterprises (ZIM) of the Federal Ministry of Economics and Technology on the basis of a resolution of the German Bundestag.
- Development of high-performance processes
- Materials development for powder, extrusion, wire and flat steel based techniques
- Functionalization of injection molding and composite components
- Contract manufacturing of functionalized prototypes
- Microstructural and mechanical characterization of additive manufactured components