Reverse Engineering with SP25 probe

[CNC MILL]

I am reverse Engineering my companies thermoform molds that do not have any documentation of what they are. I am scanning with a SP25 probe. When it scans parallel with a cavity wall it starts to search for the edge which is ok but it takes odd points during this time. Any sugestions on how to keep it from taking points while it is searching? Or any other help on reverse engineering? Brown and Sharpe suggested slowing the scan speed down but that didn't seem to help.

[Matthew D. Hoedeman]

If it is going over a sharp corner, the only way I have found to eliminate the searching is to break the scan up so that each side of the corner is a different scan (using a TTP).

Is the SP25 a scanning probe or are you going to have issues with the probe comp being a little off since Pcdmis will only comp in a 2-D plane for each scan line? If it is a probe made for scanning (ie reads the DEFLECTION and deflection DIRECTION of the probe as well as the contact) than you should be alright. If it is NOT, then you may have slightly bad data due to the fact that Pcdmis will ONLY comp for the probe in 2-D, the cut plane of the scan line, when using vector points. This is where surface points with sample hits come into play. Of course, if it IS a scanning probe, then you can just ignore this information (but the REST of you, pay attention !).

[CNC MILL]

It is a scanning probe and should be comping in 3-D. All the edges, inside and outside, have radii and all the wall have a 3 deg. draft angle.

[CNC MILL]

To anyone that ever has the same problem reverse engineering I finally got an answer. Using the SP25 scanning probe I had to use a linear scan and pattern it instead of using a patch scan. The two are similar but comp the probe differently. The probe comp in the patch scan could not handle the complex shapes of our thermoform molds.

[JamesMannes]

If you are using 3.7 mr3 there is a check box for "CAD COMP". If you check that box, it uses a different algorithm than normal. I will probably screw up the definition of so be patient. What CAD COMP does is utilize the algorithm from QUINDOS as it has a better method for defining 3D topograghy. I know it doesn't really apply for this situation, but I thought I 'd share.