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FBM for a simple Hole feature


I am new to FBM, Would like to understand the following 


I have a unparamatric solid body with simple hole fetaure with out a chamfer on the Top. When i used feature based it has recognised feature with Spot_Drill and Drill_in_Center my question is how to add the chamfer as a predefine operation for all hole in MKE.





Re: FBM for a simple Hole feature


Hi Ram, 


For instance, FBM recognizes what you have in your model. So if in the model there is no chamfer, you will not be able to create a chamfer operation with FBM. 


Probably you can trick FBM to do it, but so far I have never done something similar. 

Take a look at Chapter 2 of the MKE Training document to understand it better. 


Hope this helps you!


Salvador Peregrina
Manufacturing Team Leader| NX 12.0.2

Re: FBM for a simple Hole feature

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

To trick the system I would create a mapping rule in the machining knowledge tab with a very high priority of 9999 or similar.

The mapping would add the needed attributes for doing the chamfer, so you cheat and the remaining rules that apply for chamfers are just added to the machining process.

Stefan Pendl, Systemmanager CAx, HAIDLMAIR GmbH
Production: NX10.0.3, VERICUT 8.2, FBM, MRL 3.1.7 | TcUA 10.1 MP7 Patch 0 ( | TcVis 11.4
Development: C (ITK), .NET, Tcl/Tk Testing: NX12.0 | AWC 3.4 Preparing: NX12.0

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Re: FBM for a simple Hole feature

Siemens Phenom Siemens Phenom
Siemens Phenom

Hello Ram,


the ootb machining_knowledge.xml has a setting for this situation.

It is a constant named bool_Always_Chamfer_Features_Yes1_No0.

If you switch this from the default value = 0 to 1, then you should get a spot drilling operation that goes deeper and creates a chamfer before drilling.




However, when testing this, the spot drill depth is not adjusted.

You must again use MKE and edit the rule named Spot_or_Chamfer (find it under MillDrill->Drilling->SpotDrill.

The conditions needs an extra expression to define the Depth properly:


IF mwf.DIAMETER_2 <= constant.Small_Value AND constant.bool_Always_Chamfer_Features_Yes1_No0 = 1 THEN = "Spot_and_Chamfer_Always" AND
oper.Predefined_Depth_Status ="true" AND
oper.Predefined_Depth_Type ="PartUnits" AND
oper.Predefined_Depth_Value = mwf.DIAMETER_1 + constant.geo_Depth_Top_Chamfer


It should look like this in the MKE:




For smaller holes ( Diameter <= 12 mm) the selected operations with and without modeled chamfer are then identical:



Thank you !


Reinier Capelle
NX CAM Development - Customer Success

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