Step 242 files 1

[Troy442]

I hope I am in the correct area. I did a few stp242 searches and found no results.

For generic 3D CAD file outputs, step 203 and 214 are now part of step 242. Does anyone know what advantages were made (if any) on the CNC machining side?

As a simple example say a 3D CAD feature is 40mm +3/-0. This tolerance is annotated in 3D or created with SolidWorks MBD (model based definition)package. Will the CNC machine aim for the nominal 40mm from CAD? Meaning a failed part if just undersized. A human machinist might not go for the "perfect" 40mm.

Does step242 slow the tool path based on tight tolerances in 3D? Any machine change for surface finish? With GD&T does it know anything about tolerance, MMC, MMB etc. If the designer drives a tolerance to zero and uses only "bonus tolerance" (I know some hate that term, so shift)does the CNC follow those criteria?

***BASICLY, is there any smart intelligence between the CAD output STP242 and a CNC machine?***

Thanks for your time, Troy

 

[JNieman]

Are you possibly confusing STP242 with STEP-NC?


STP242 is more of a combination of 203/214 with the ability to universally transfer PMI information regarding the geometric properties, tolerances, finishes, and other requirements within the model itself.

You still have to program your machines based upon the model information. Additionally, post processors are very machine-specific as you get to more advanced features, and varying controller manufacturers. It would be very difficult to create a universal machine language model.

There's also no 'right answer' for how your cutting strategy goes. It's based upon the machine, the cutting tool, the material, and many other variables. There is no "below a tolerance of +/- .xxx feed 20% slower" to just make an 'easy button' for making parts.

 

[drawoh]

Troy442,

When sending out computerized information, always select the lowest common denominator. You do not know what the other guy can read. I am actually not all that familiar with the STEP standard. I assume that STEP 203 is the format most likely to work at the other end, and that is what I send.

For communication purposes, bleeding edge technology usually does not work.

--
JHG