One definition (my own understanding):
Product Manufacturing Information (PMI) is a set of tools that allows you to attach non-geometric information to a CAD item in pursuit of higher-level workflows like MBD (Model Based Design) or MBE (Model Based Enterprise) . The eventual idea is that your model will contain all the info it needs to be designed and manufactured.
The most common workflows are info like Surface Finish, Dimenion Tolerances, etc... Things that were traditionally put in 2D drawings as text, notes, "funny graphics" and often had to be interperted by the Manufacturing Engineer (or worrse, perhaps, they were not put anywhere and the Manufacturing Engineer had to figure it out themselves, and may not have documented those decisions anywhere, or if they did it was in a seperate document that might not be tracked).
I'm sure there are folks here with much more Manufacturing experience than I that can expand on this.
I believe the goal is that CAM should be able to recognize the PMI and decide on the proper manufacturing strategy "automatically"
For instance, a nominal "half-inch" hole could be:
- just drilled (large tolerance, and short L/D so spot drill not required)
- spot drill & drill (perhaps due to longer L / D)
- spot drill, drill and ream (diameter tolerance and/or surface finish require ream)
- spot drill, drill and bore (position tolerance is tight)
- spot drill, drill and bore and ream
- spot drill, drill and ... and jig-grind
- wire EDMed
If the PMI data is on the model, then it can be used to select the proper manufacturing process for the hole (automatically, with possible assistance from a human).
If that data is not on the model (e.g. on a drawing or not specified anywhere) it REQUIRES human input to define the process.
Production: NX10.0.3.5 MP16/TC11.2
I'd rather be e-steamed than e-diseaseled
CAM and CAD/PMI are already connected in NX CAM with Feature Based Machining (FBM) application. If for example, one hole has H7 tolerance, it will be machined differfently with FBM than the hole with no tolerance. The same would be with surface texture symbols. If you place such a symbol on a surface, it will be machined differently (according to the symbol and FBM rules).
An example of this can be seen in the following movie:
At approx. time of 6:50, you can see, that the pocket has already Ra defined.
Hope that this movie helps in understanding of the connection between PMI and CAM in NX.