Metal laser melting
Advantages of metal laser melting
- Capable of making components that until now have been technically non-manufacturable (e.g. components with internal cooling ducts, cavities, lattice structures etc.)
- A finished component can be made from a 3D model
- Quick component production
- Capable of significant weight savings and high rigidity (skeletal design)
- No rig and tool costs involved for prototypes
- High-quality products, low warping due to uniform component cooling
One or more 3D models (STL format) are placed in the installation space on a base plate and provided with support.This is used for:
- Heat dissipation
- Support of critical contours
- Orientation of the components:
The component should be aligned on the base plate so that the support structure is as small as possible.
- Attach the support structure:
The support structure must be placed at points where the contour cannot be melted onto an existing contour or where the contour deviates greatly from the previous layer (< 45°; radius > 3 mm).
- Remove powder:
The base plate with the parts on it is removed from the loose powder.
- Thermal treatment:
fter production, the parts can be thermally treated to reduce residual stresses and improve properties and metallurgical structure.
- Removal of the supporting structure and mechanical finishing:
The parts are detached from the base plate. Other support structures are removed mechanically. Parts can be mechanically reworked to meet critical tolerances.
- Surface treatment:
Parts are further processed, for example, by blasting, polishing or vibratory grinding.
- Direct production from CAD data
- Layered construction of the components
- Homogeneous microstructure, density > 99.6 %
- Full mechanical properties
Fields of application
- Prototypes for functional tests
- Single parts and small series
- Moulds for injection moulding -> contain near-contour cooling channels
- Spare part replica for decommissioned series
- Conventionally unworkable parts
Characteristics / Restrictions
- Smallest possible structure size: 0.04-0.2 mm
- Accuracy: +/- 0.05-0.2 mm (+/- 0.1-0.2%)
- Smallest layer thickness: 0.025 mm
- Typical surface finish: 4 - 10 microns RA
- Density: Up to 99.9%.
- Minimum wall thickness: 0.25 - 0.5 mm
Metal laser melting
Selective laser melting (SLS) is a generative production process in which the desired component is produced directly from 3D data. Based on the available data (standard format STL), highly complex parts can be produced from different metallic materials.
Due to the lack of a uniform naming convention for the process, it is also known as laser melting, additive manufacturing, selective manufacturing, SLS 3D printing, generative manufacturing, laser melting, laser cusing, laser sintering, 3D printing metal, 3D laser sintering, etc.
Selective laser melting in detail
With the SLM process, the workpiece is built up three-dimensionally in layers. The metal is applied in very fine powder form in layers and melted by the laser beam where the workpiece is to be produced. Depending on the surface quality and production speed required, the powder is applied in layers between 20 and 80 μm thick. A powerful fiber laser then melts the intended areas selectively. The strong focusing gives the laser beam a very high power density, with which the material is melted with absolute precision. This makes it possible to produce 100% dense workpieces with low wall thicknesses.
Once the melting process for the layer has been completed, the platform is lowered by the respective layer thickness so that a further powder layer can be applied. In this way, the workpiece is produced layer by layer.
The duration of the process, which takes place in a closed inert gas atmosphere (argon), depends on the amount of material used and the number of layers - not on the complexity of the component.
The layered structure makes it possible to create filigree grid, mesh or net structures, porous structures or irregular channels in the workpiece that cannot be produced with other processes. The material is only constructed where it is required for the intended application and future stress. For example, the weight can be minimized by optimizing the use of materials.
SLM is used to produce 100% dense parts that can withstand high mechanical loads and whose material properties are almost identical to those of conventionally produced parts. This means that they can be reworked as required using any other process, depending on the intended use.
The use of the SLM process is generally more economical than conventional processes when the production of single pieces, individualized parts or series with small quantities is required. The cost advantage is usually greater the smaller the number of pieces, the more complex the individual piece and the lower the material input.
Directly from the design data of the CAD program, functional metal parts are created in a very short time in the Concept-Laser system, whose mechanical load capacity corresponds to that of conventionally manufactured workpieces.