4.16 Oxygen Face Mask - Industrial

4.16.1 Background

An industrial designer needed to design a new facemask with some features of an existing facemask. The aim of this study was to capture the geometry of an existing facemask and apply it in the design of a brand new oxygen facemask.

Krugersdorp Private Hospital was again approached to perform the CAT scanning. A series of coronal sections were produced. The data was retrieved and converted according to the data conversion procedure. The next step was to supply the data to the designer so that it can be used in a meaningful method.

4.16.2 Conclusion

This reverse engineering method was successfully applied to supply the industrial designer with unique results. Again, this method proved to be the only non-destructive method to perform this reverse engineering method. The mask was made of Silicon elastomer. No contact type reverse engineering method could be used to capture the masks geometry. The mask would deform as the touch probe anticipated to sample 3D coordinate points. 3- and 4-axis laser scanning devices could also not be used due the facemask’s geometry. The face mask geometry featured a deep undercut where the laser would not be able to enter. Accuracy again did not prove to play a critical role in the project that made the CAT scanning method the ideal method for reverse engineering. Images

Isometric view of the cross sections used in the CAD file to design the new mask.



Isometric view of the CAT scanned 3D reconstruction.


2D CAT scanned Slice 119 of the face mask(yellow section)



2D CAT scanned Slice 89 of the face mask(yellow section)


3D CAT scanned reconstruction of the facemask. Undercut section.



4.16.3 Oxygen Face Mask Data Sheet:
  Description Options (Default) Data


1 CT Image Names   CT1-60
2 Patient/Project Name   mask.pat
3 Number of First Input Image   1
4 Number of Last Input Image   60
5 Number of First Output Image   000
7 Horisontal Nr. Of Image Pixels 0 to 65535 (265,512,1024) 512
8 Vertical Nr. Of Image Pixels 0 to 65535 (265,512,1024) 512
9 Number of Images per File (1) 1
10 File Swap Format (0,3) 0,3 0
11 Pixel Type B,UB,S,US,L,UL,F Ccelcint
12 Header Size *see formula below -
13 Inter Image Header Size 0 -
14 Add Value 0 to 4095 -
15 Scale Value 0 to 4095 -
16 Table Position (mm) 0
17 Distance Between Slices (mm) 3
18 Slice thickness (mm) 3
19 Pixel Size SQ. F.O.R./Nr. Hor. Pixels (mm) 0.3
20 Gantry Tilt Angle Degrees 0
21 Field of Reconstruction/View (mm) 150
22 Number of Images   60
23 File Size of CAT Image kb 55-60
24 File Size of Converted Image kb 16
25 .3dd file size Mb 0.645
26 .STL file size Mb 4.6
27 RP Method (SLA,FDM,OTHER) -
28 .IGS file size Mb -
29 RP Slice file size Mb -
30 RP Download File size Mb -
31 Grow Time Hour -
32 Tip size (T12, T25) -
33 Slice Thickness (0.01", 0.014") -
34 Finishing Time Hour -
35 Processing Time Hour 5
36 Data Retrieval Time Hour 2
37 Total Cost Rand =7*100+2500=3200


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