4.9 Motor Car Door Mirror Rubber Seal - Industrial

4.9.1 Background

Once again the geometry was required that was used to produce injection mould tooling. The rubber seal was taken to Krugersdorp Hospital to capture the geometry. One millimeter thick slices were required to obtain sufficient detail of the sealís geometry. Three data sets of sixty slices each were made due to the maximum amount of slices that can be scanned at one time. The limitations are related to the computer processing capabilities, hard drive space and X-ray tube cools down periods. The seal was aligned in two axis with the visual aids available on the CAT scanner. A flat section of foam was used to suspend and separate the seal from the scannerís table. This would help in later during the data conversion and processing stages. CAT scanning took place at 130kV.

4.9.2 Conclusion

The threshold, type of material and material cross sectional wall thickness here plays a cardinal role. One can easily adjust the threshold to vary the wall or cross section. Any imperfection will also be captured with this method. A fair amount of editing can be applied to solve this problem. If the material cross section is to thin or if the material density is too low, a poor CAT image will be generated. To improve the poor data that was captured, the threshold can be increased. The threshold can be increased to such an extent that the 2mm-wall thickness can be thickened to 3.5mm. It is therefor important that some form of reference or verification is implemented every time. It is also required by the ISO 9000/1 standards, that results and processes can by traced and verified. It was again clear that the correct tools are still not in place at the TCT, CSIR, to perform the tasks. STL data manipulation tools are requited that can perform boolean operations, section 3D STL geometry, fix and verify STL data, tools that can generate machine tool paths from STL data. STL format is one of the easiest data format obtainable from RE, and it is therefore important to have the correct software programs that can manipulate STL format files. Images



Figure 4.9.2 .1

3D reconstructed image of the motorcar door window rubber.


Figure 4.9.2 .2

3D reconstructed motorcar door window rubber.



Figure 4.9.2 .3

3D reconstructed motorcar door window rubber.

Figure 4.9.2 .4

3D reconstructed motorcar door window rubber.


4.9.3 Rubber Seal Data Sheet:
  Description Options (Default) Data


1 CT Image Names   mirror.00
2 Patient/Project Name   spiel.pat
3 Number of First Input Image   mirror1.000 @ 34.5
4 Number of Last Input Image   mirror1.147 @ 179.8
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 CCELSC
11 Pixel Type B,UB,S,US,L,UL,F -
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) 34.5
17 Distance Between Slices (mm) 1
18 Slice thickness (mm) 1.2
19 Pixel Size SQ. F.O.R./Nr. Hor. Pixels (mm) 0.684
20 Gantry Tilt Angle Degrees 0
21 Field of Reconstruction/View (mm) 350
22 Number of Images   147
23 File Size of CAT Image kb 27
24 File Size of Converted Image kb 19-22
25 .3dd file size Mb 0.234
26 .STL file size Mb 8.9
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 1
36 Data Retrieval Time Hour 3
37 Total Cost Rand 600+800=1200


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