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2 Cylinder Steam Powered Compressor

posted Mar 27, 2013, 7:11 PM by Jay Gross   [ updated Sep 30, 2013, 4:25 AM ]
This is a complex project. Scanning was a challenge because of the cooling fins, recessed areas, black color and the area behind the two shafts with oil seals. Around 120 individual scans were pieced together. We were able to get a water-tight mesh as needed for rapid prototype production from an almost complete 3-D scan data mesh. This was offered as a lower cost solution. The level of detail and corner sharpness was not good enough and the part was then fully modeled using 2 different CAD packages. (This part was too complex to model directly from the scan data, so an intermediate CAD program was used.) A very precise and clean water-tight mesh was obtained from the final CAD model. You can read more about this part in Interesting Projects.This part appears with permission from Wayne Godshall of Godshall's Custom Machining.
Here is the original part.  The right side picture shows the light blue 3-D scan data over the grey solid model.

The first picture shows the scan data of the middle after cleanup. The second picture shows the detail of the solid CAD model just before getting the final touches. The seals around the shafts were redone by hand since the backside of the shafts cannot be seen by the scanner.  Scale modelers will use polished steel shafts and real rubber seals here to be more realistic. Bolt heads can be added to the CAD model and cleaned up after fabrication with a file.  As an alternative, the CAD model can be split along the original casting seams to get drill bit clearance and then can be drilled out after fabrication for real bolts.