Non-Destructive Inspection of AM parts by CT

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Thomas Kleinteich.

Here you can participate in a manufacturing quiz, with which you can check your knowledge about this event item. We will announce the winner of this quiz after fourteen days by email to all event participants. The best entry wins a visit to TPW and a free scan of something the winner proposes (may be something private of course), dimensions will have to be coordinated with TPW.

Below are the names of the entries:
1) Bart de Vries (ASML) WINNER
2) Jiri Rados (Frenckengroup)
3) Dylan Sikkelbein (HitTech)
4) Tom Raasveld (ASML)
5) Wouter Bunthof (Frenckengroup)
6) Giorgos Zografos(Frenckengroup)
7) Sander Broers(ASML)
8) Karthik Panineni(Frenckengroup)
9) Anne Berkvens(ASML)

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Non-Destructive Inspection of AM parts by CT

(1) Which parameter, according to Lambert-Beers-Law, has the strongest impact on the captured intensity of x-rays on the detector after they passed through a part?(Vereist)

Density of the material

Wall-Thickness of the part

Atomic number of the material’s elements

2) What can a 2D-x-ray image of an AM-part be used for?(Vereist)

Measure the material volume

Visualization of large “geometrical” deviations such as remains of supportive structures or accumulations of entrapped powder

Determine the precise position of gas pores in the part material

(3) What kind of information does the CT-scanner hardware capture?(Vereist)

2D x-ray projection images of the sample while it rotates

Slice images of the sample

The 3D part geometry

(4) How shall the part be placed in the CT-scanner?(Vereist)

It doesn’t matter because the full volume of the part is captured anyways

In an orientation that minimizes the summed wall-thicknesses, which must be penetrated during the x-ray imaging process, but also at a slight angle.

Aligned to the main axes (length, width, height) of the actual part

(5) What is a voxel?(Vereist)

Synonym to pixel

A description of the systematic measurement error when performing metrology on a CT-dataset

A volumetric pixel = the smallest sub-unit of a CT dataset

(6) A foreign particle, that has higher x-ray attenuation as the base material of the inspected part appears in a CT dataset as:(Vereist)

Dark structure

Light structure

It is not visible at all because material differences cannot be captured by CT

(7) The detector of a CT scanner has 2.000 x 2.000 pixels. In which range will the resulting voxel size of the reconstructed CT dataset be for a part that has the dimensions: 250 mm x 130 mm x 70 mm?(Vereist)

App. 40 µm

App. 70 µm

App. 130 µm

(8) Can a gas pore with a diameter of app. Ø 5 µm be detected in a CT scan with a voxel size of 50 µm?(Vereist)

Yes

No

It depends on the location of the pore

(9) To safe inspection costs, two samples are placed in one CT scan. The resulting voxel size of the scan is 60 µm and the dataset for each part is 1,2 GB large. How large would be the resulting dataset for one part, if the parts are scanned separately at a voxel size of 30 µm?(Vereist)

2,4 GB

4,8 GB

9,6 GB

10) What could be the advantage of using CT when inspecting metal 3D printed density cubes as compared to classic metallographic inspections?(Vereist)

CT has the better spatial resolution

CT allows to visualize the microstructure of the material

CT captures the full 3D geometry of the cube and hence allows to find voids independent of their position in the sample

Versturen

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