Hello everyone, I am running into a few problems. I have encountered them before and never really got it all figured out. I will be able to post some code tomorrow West-Coast morning but being at home I am just going to explain the situation. I believe this is an issue of alignment (isn't it always!) but it has multiple factors.
I have a tricky part. It has with irregular geometry, curves, a hyphenated ( A-B primary Datum made from two separate planes at different locations in Y as I have the part on the fixture), features at angles not square to the machine or the datums, tight tolerances, a Datum Structure that aligns the part at a angle not 90 degree to other features or the machine, a small surface to locate the part on the table and square it up before probing. On top of this I don't have a lot of time!!! Here are some issues I run into.
I import the CAD model and use transform to place the tri-hedron in the center of a cylinder that is the 2nd Datum (It will eventually datum's X and Z origin) and I continue using the transform command to get the tri-hedron not only centered and aligned to that 2nd Datum cylinder but also flush with one of the previously mentioned hyphenated A-B planes. I use a read point to align the X-Y-Z translation before I do any probing. Within the alignment command I translate X-Y-Z to the read point and I also offset the Y origin by half of the probes ball diameter. I do this so if you drive the probe's ruby tip centered as best as possible with the 2nd Datum cylinder and also the surface of the ruby tip as close as possible to touch where primary datum plane would be if the cylinder wasn't there.
I probe the cylinder and use it to take away as many degrees of freedom the cylinder can. I then probe the hyphenated A-B planes and a bit later I use Constructions to create a mid-plane from them that I eventually define as the primary Datum. I probe the 3rd Datum (it is a slot that works with the 2nd datum to take away rotation about y).
Hopefully you follow- as I said earlier I will provide code tomorrow.
I define my datums and then I align to the datum structure. Here is where I run into one of the issues I hope to clarify. The CAD model and the outlines of features I probed are visibly not aligned. I am not sure if this is indicative of a real problem but it sure seems like and it bothers me....
Now when I go to probe some diameters that have true position to the datum structure it shows the diameters as impossibly out of position. The diameters are in a surface that is 69 degrees away from the primary A-B plane and I use a probe head B rotation that is 67.5... If i use an auto-feature the diameters are very far out. If I use individual points and construct a circle I get much better results.
Around the diameters are some widths that are true positioned. I try to probe them with lines and use Constructions to make widths and again the results are impossibly bad.... Last thing I want to mention is there are also some profile tolerances applied to some surfaces and again they are wildly out.
Manual checks disprove the machines results of extreme out of tolerance features....
I am not sure how to get this mess of a situation resolved. I can help clarify anything about this and post code tomorrow.
Thanks!
