Hello, have been reading this forum for a while now, great source of information. Recently question came up about measuring method so I would like to get advise from the experts. Based on the drawing datum A is the surface of the the stamped part, datum B is is a hole without any positional tolerance and than there is a round slot. Length and width of the slot are dimensioned separately. Length of the slot is marked as datum C and has non diametrical TP 0.25 MMC, A, B MMC with the associated basic dimension of let say 4.5 mm in X direction (looking at the drawing length is in X and width is in Y). Width of the slot has also non diametrical TP 0.25 MMC, A, B MMC, C MMC with the associated basic dimension of let say 17 mm in Y direction. Both hole and the slot are on the same plane A . At some point insert stopped fitting so measurements started at both ends (our company and supplier). My results were showing TP out with center of the slot being only 3.7 mm in X and 17.15 in Y. Company which makes inserts admitted their punch was loose but said position is still in spec. I was setting alignment by measuring 2 radiuses of the slot, creating line between their centers and rotating alignment to it, they simply used 4.5 mm basic to create offset alignment which also automatically made 17.15 in Y shorter and almost perfect. They are also reporting TP of the slot's center in only one direction since in the other direction would be perfect based on the offset. I presented position in 2 directions (thanks to all the posts regarding generic features and variables), also tried explaining that TP callout is not only for the center but any point along slot's axis. I need some confirmation or correction to my method.
Base on CAD none of the slot axis are squared with the CS, based on the drawing axis along the length is in X, hole is above and to the right of the center of the slot
If the length is parallel to X, then the slot is an offset as Matt wrote.
So, you need to find the center of the slot length (I would measure as a square slot also). Then create an offset line from B and C, with C offset by the basic. Use that for rotation.
Or, as Matt wrote, use iterative. But then you will have to measure the slot and construct a cast point on the slot, as PC-DMIS will not allow you to use the slot length to rotate to directly.
Base on CAD none of the slot axis are squared with the CS, based on the drawing axis along the length is in X, hole is above and to the right of the center of the slot
If the length is parallel to X, then the slot is an offset as Matt wrote.
So, you need to find the center of the slot length (I would measure as a square slot also). Then create an offset line from B and C, with C offset by the basic. Use that for rotation.
Or, as Matt wrote, use iterative. But then you will have to measure the slot and construct a cast point on the slot, as PC-DMIS will not allow you to use the slot length to rotate to directly.
