I'm running a part on Sunday, main datum is a half external sphere. It measures 5.5mm diam using least squares BF, in tolerance, all is good. All vector pts, lots of them prob 40-50, constructed sphere. I mic it for fun in varying angles and get 5.51mm. Totally acceptable diff being lst sq vs Mic and all the other errors floating around.
So I decide to run it at minimum circumscribed....should be larger than lst sq, no? Welp....i get 5.48mm. How could min cir be less than a lst sq? I'm baffled.
I fixed all those grammer errors...im aware of what all the fits are...ran 5 separate runs both with lst sq and min circ, all slightly twisting the part 1 deg for variance. i know they arent stable but its hard to believe the results were all near identical and there are plenty of pts to use...and its a full 180 deg...at the boarderline of too little but i figured enough.
Were you using BF or BFRE to construct the various fits?
Did you include any outlier filtering?
How much of the sphere were you measuring - how many degrees of arc?
What was the total form error?
Do you still have the data and if so, can you share it?
Were you using BF or BFRE to construct the various fits?
Did you include any outlier filtering?
How much of the sphere were you measuring - how many degrees of arc?
What was the total form error?
Do you still have the data and if so, can you share it?