Center Additive Manufacturing


The Center for Additive Manufacturing (ZAF) combines various generative manufacturing methods, which are conceivable for rapid prototyping as well as for larger sample numbers. The spectrum of methods ranges from plastic-based processes such as selective laser sintering (SLS) or fused-deposition modelling (FDM) to UV-curing polymers in stereolithography (SLA) and the multijet process to the processing of metallic powder materials using selective laser melting (SLM).
At ZAF, not only individual parts can be produced for test purpose, but feasibility studies on the use of different processes for different materials are also offered, including on-side materials characterization.


Additive Manufacturing of Plastic Parts

Desktop Fused Deposition Modeling


Fused Deposition Modeling (FDM) describes the layer-wise distribution of molten plastic filament through a heated nozzle onto a build surface. Small scale FDM printers offer a wide range of usable materials and are often used for early phase functioning prototypes and design studies.

Use cases and advantages

  • early design phase functioning prototypes
  • small scale and ease of use
  • cost effective
  • huge range of materials and colours

Industrial Fused Deposition Modeling


Industrial FDM while being the same in function as its smaller desktop counterpart enables the use of materials with high-strength properties through a higher process temperature.

Use cases and advantages

  • big built volume
  • fast printing
  • engineering materials
  • solvable supports

Stereolithography


Stereolithography stands for the curing of UV-active resin using a laser beam. The build surface on which the part is being built is lifted layer wise out of a resin bath. Due to the small size of the laser spot and minimal layer thickness SLA offers high precision and high detail finishes.

Use cases and advantages

  • high resolution and detail
  • high surface finish
  • clear printing

Material Jetting


Material Jetting technology distributes resin over the build surface which is immediately cured through an UV-light. Multiple small nozzles offer not only an ultra-high resolution but also the blending of up to three materials. This allows printing in full colour with distinctive borders or gradients as well as a shift between two materials with different properties (e.g. stiff and flexible).

Use cases and advantages

  • high resolution and detail
  • surface finish
  • clear printing
  • full colour (borders and blends)
  • multiple properties (borders and blends)

Selective Laser Sintering


Selective Laser Sintering describes the sintering of plastic powder which is layer wise distributed onto a build surface.

Use cases and advantages

  • no support needed
  • high strength prototyping
  • high detail
  • nearly isotropic characteristics
Additive Manufacturing of Metal Parts

Selective Laser Melting


Selective Laser Melting is characterised by layer wise distribution of metallic powder onto a planar build surface. Usage of high power laser to melt and fuse metallic powders into dense objects.

Use cases and advantages

  • full metal 3D printing
  • high strength
  • high detail
  • high resolution

SLM Hybrid Milling


SLM Hybrid Milling combines the SLM technology with high speed CNC milling. In this way the contour of the part can be overmilled successively to produce high end surfaces.

Use cases and advantages

  • All SLM advantages
  • surface finish
  • exceptional contour and size accuracy
  • only CNC milling process where deep slots and cavities are possible
3D Scanning

Structured Light Scanner


3D Scanning allows for the digitalisation of real world objects. Scanned objects can be altered or used to fit 3D printed applications to. Trough high precision digitalisation 3D scanning can also be used to compare the manufactured part to digital origin to evaluate the process accuracy.

Use cases and advantages

  • digitalisation of real world objects
  • high precision, high detail
  • full colour scanning
  • comparison of produced part to digital origin
Post-Treatment

Hot Isostatic Press


Hot Isostatic Pressing describes a heat and pressure treatment of printed objects to reduce their remaining porosity to a minimum. The process subjects the object to high pressures from all directions and elevated temperatures to eliminate internal voids and microporosities.

Use cases and advantages

  • ~100 % theoretical density for SLM printed parts
  • reduction of thermal stresses
  • increased mechanical properties (e.g. fatigue, wear, lifetime)
  • heat treatment steps (hardening, annealing, softening) can be included in the HIP cycle

Heat Treatment


Heat Treatment is used to eliminate thermal stresses which can occur during the manufacturing process. Further specific mechanical properties by following a temperature profile can be obtained. The furnace can also be used to sinter metallic powders and fire clay and ceramic materials.

Use cases and advantages

  • annealing of metallic and plastics parts
  • tailoring of mechanical properties
  • sintering of metallic goods
  • firing of ceramics

Laser Hardening


Laser Hardening allows for local surface hardening of functional areas of metal parts. The quenching of the material happens trough the remaining not exposed matter.

Use cases and advantages

  • localised surface hardening
  • very thin surface hardening

Laser Engraving


Through Laser Engraving not only inscriptions like labels and symbols are possible but also specific surface finishes and functional interfaces can be achieved.

Use cases and advantages

  • inscriptions, labels, marks
  • different shades through annealing colours can be achieved
  • creation of specific surface finishes and functions

Sandblasting


Conventional Sandblasting is used to achieve desired surface finishes and can be used to clean off possible remains of support structures.

Use cases and advantages

  • removal of support remains
  • even, clean surfaces
Testing

Metallurgy


To analyse new materials and to realise a steady process control objects can be tested under metallurgic aspects.

Possible analyses

  • creation of polished cut images
  • microscopy (optic, REM)
  • dilatometer tests (thermal expansion coefficient, melting point, ...)
  • roughness measurement
  • determination of density
  • (...)

Mechanical Analyses


To determine usability of manufactured parts a variety of mechanical characterisations can be undertaken.

Possible analyses

  • tensile testing
  • hardness testing
  • (...)

Powder Analyses


The quality of SLM and SLS printed goods greatly depends on the quality of the used source powders.

Possivle analyses

  • powder size and distribution analysis
  • powder sphericity determination
  • powder flow rate testing
  • moisture analysis
  • (...)

Chemical Treatments


Plastic and metal additive manufacturing can be quality controlled using various chemical analysis. Especially for plastic 3D printing specific surface properties can be achieved as a post-processing step.