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VTT Pipe case study



A mock-up SLM test component was designed at VTT for assessment of printability and geometric accuracy both before and after machining. Design principles and objectives included:

  • Features suitable for SLM, e.g. self-supporting elliptic cross-section for horizontal pipe, ribs and local details to modify overhanging members to be self-supporting
  • Inclusion of features challenging to manufacture by SLM that are common in industrial components, e.g. thick sections and overhangs
  • Smooth transitions used at corners for good fatigue strength
  • Only functional surfaces are designed to be machined
  • Bolt holes are reamed using pre-fabricated holes
  • Dimensions limited so component can be produced in SLM125HL chamber


For more information on design guidelines for additive manufacturing, take a look at our report:

Design guide for additive manufacturing of metal components by SLM process 


Click images to enlarge.


Experimental Approach

At VTT we have printed this part several times with variations in material, process parameters, and the upper collar support design. Experimental data was collected during and after printing for use in:

  • Improving the design approach
  • Optimizing print process parameters and heat-input
  • Testing the ability of AM process simulation software to predict thermal build-up and distortions during and after the build, as well as component stress state of the component as-built and after post-treatments.






Click images to enlarge. 

Knowledge Sharing

In order to encourage knowledge sharing and an open approach to research in this field, VTT would like to offer this case to others who would like to use it for experimental work or AM process simulation validation. The relatively small differences in the upper collar support design have a significant effect on the heat conduction from the top-flange, requiring a more controlled heat input for successful printing. Please find below a link to download the VTTPipe geometry (.stp file format) with three different design variations of the upper collar support design:

  • VTTPipe_ID171 - should print fine with known imperfections and slight distortions
  • VTTPipe_ID172 - more challenging upper collar support design, but should be printable with controlled heat input and cooling
  • VTTPipe_38degCollar - very challenging upper collar support design to print, requires controlled heat input during build to avoid failure
  • Video summary - video summarizing the creation, evaluation and ongoing work with this the mock-up test component


DOWNLOAD VTTPipe design files

The CAD-files are free to download but when used VTT must always be credited as the source.

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