Detection of dents

[[Fi...]]

Dear Community,

I am looking for a way to detect small dents and scratches in slightly curved surfaces. I am not completely satisfied with my approaches and wanted to ask for further tips and ideas.

I did the surface meshes with an ATOS CompactScan with an MV700. I am still using Zeiss Inspect 2023 as software. I only have the actual geometry from the 3D scan and no CAD data with which I could carry out a surface comparison. My aim is to show the deviations on the actual data.

 

I have tried the following approaches:
1. create a "Smoothed surface from mesh..." on the surface mesh and perform a "Deviation to geometry ..." as an inspection. The smoothed surface here looks usable to me, but the deviations are displayed on the smoothed surface, some of which has very large polygons and therefore does not display the distances correctly. The area of the dent is marked in red but not shown in the analysis. Is it possible to display the distance on the actual data?

2) I have created a "Fitting polynomial surface" of the 2nd degree on the surface mesh and again carried out a "Deviation from geometry ...". This is closer to what I am looking for. But here too, I would prefer to display the comparison on the actual data, as this information is forwarded for further processing.  

3. creation of a "fitting cylinder" on the entire curved surface. Here I am not able to create a surface comparison between cylinder and surface.

Do you have any other ideas, tips or approaches that I could pursue?
Best regards
Fiete

[[Na...]]

Hi Fiete,

for this application you can create a surface defect map (comparison):
https://techguide.zeiss.com/en/zeiss-inspect-2023/article/cmd_comparison_create_multiple_surface_defect_map.html

There is a virtual grindstone moved along the surface and dents or bulges can be detected. If you follow the approach on nominal -> referenced construction -> compare actual and nominal, the curvature of the surface will not affect the results. The defects may later be classified by formulas, e.g. deep and long defects will be class 1, round and shallow defects class 2. 

This function is easier to use in Inspect 2025 by the way.

Nanno

[[Fi...]]

Hello Nanno,
Thank you for your reply.

I have found the function, thank you very much for the tip.
I have now also upgraded the software to Inspect 2025.

Is there a way to automatically determine the size (width and length) of the dents? I have played around a bit with the surface defect elements, but I think I need other prerequisites for this. 

Best regards,

Fiete

[[Na...]]

Hi Fiete,

you need to follow up with a defect classification. But I would recommend to contact the support with a concrete data set.
https://techguide.zeiss.com/en/zeiss-inspect-2025/article/cmd_comparison_check_scalar_defect_classification.html

Nanno