Showing results for 
Search instead for 
Do you mean 

Expressions in CAM

Way back when, at the last PLMworld (May 2015) we had a CAM open Forum session.

One of the issues raised was allowing expressions in CAM (*I THINK* some dialogs allow them to be used for input, but the value of the expression is saved, rather than a link to the expression itself).


As there are tens (if not hundreds) of thousands of parameters in CAM dialogs, Siemens indicated this is a HUGE task, and wanted some feedback from users as to which specific dialogs/parameters users are interested in having the capablity of using expressions.


So, here we are 5 months later, I'm finally getting around to asking YOU (users)...


Where (specifically) would you want to use expressions in CAM dialogs, and maintain the link to the expression (so if the expression changes, the CAM stuff updates)?


Some thought on my part:

- The ability to specify stock values

--- turning rough stock in turning methods or operations

--- blank stock derived from offsetting part or using bounding box / cylinder/sphere

- linking cutoff tool width to expression / sketch values



Your (beyond "fashionably late") ex-CAM SIG chair.


Ken Akerboom Sr CAx Systems Engr, Moog, Inc.
Production: NX10.0.3.5 MP5 + patch/TC11.2
I'd rather be e-steemed than e-diseaseled


Re: Expressions in CAM

Great they are finally getting around to this. I already put in a few ERs on some parameters. Ones I can think of off the top of my head is linking pitch or threads per inch to threading operation, position for the "from workspace" IPW and drilling depths.

Using NX

Re: Expressions in CAM

Another area you need to think about is what happens when an operation is copied to another part, by creation from a template or copy/paste.

Should the operation simply reference the expression with the same name in the current part?

And of course, what should the system do if that isn't valid for any number of reasons?


As Ken eluded to, changing all CAM parameters to expressions is not realistic, so we need to look at the most common needs. This might lead us to more specific, but realistic solutions. This is how we ended up with the %Tool intent - when we asked users what they wanted to use expressions for, the #1 answer was to reference the tool diameter.  


Mark Rief
Retired Siemens

Re: Expressions in CAM

"aluminum2" -

Note I am NOT a Siemens employee.

This does NOT mean they're getting around to this.

Just that (in May) they asked for feedback from users, so (as ex-CAM SIG chair) I'm helping them out by asking you (users) where you're looking to do this.



Ken Akerboom Sr CAx Systems Engr, Moog, Inc.
Production: NX10.0.3.5 MP5 + patch/TC11.2
I'd rather be e-steemed than e-diseaseled

Re: Expressions in CAM

[ Edited ]

Not sure if I'd want any expressions created by cam.


Having the ability to link a value to an expression like with attributes would be great. 


We have a ugopen program that looks for attributes on a cam object and updates values.

The program parses the uf_param_indicies.h file and matches attribute names to #defines.

ie, if an attribute is named starting with "UF_PARAM_name" it updates the param with the attribute value. (uses UF_PARAM_name[idx] for Params that are arrays)

Attribute values can link to expressions.

This works with varying success.

I was trying to extend this to link all values between operations so i could have left and right handed programs update using an attribute named "UF_LINK_operation_name", this had less success unless I limited it to non tag values. As you say there are many indicies.


To answer the original question. We mostly use this for linking:


  1. Surface drive Tool axis relative to drive/part angle
  2. Surface drive step values
  3. floor stock
  4. check stock
  5. any stock that's not in a method or geometry object
  6. depth of cut
  7. drill peck values
  8. min clearance values

I'm sure there are many more that would help with relability and productivity.


Having more values linked to Geometry/Tool/Method objects would reduce the need for expression links (eg stock and clearance)


Off topic.


While we're at it having a bulk update of linked dependencies would be great, clicking all those ticks can get frustrating.



Re: Expressions in CAM

Many stocks can be specified in methods to inherit them from one source.

Changing one method should be easy enough for mass editing stocks.


May be extend the amount of stocks to be inherited from geometry and method groups, which uses existing functionality and is therefore easier to implement.

Stefan Pendl, Systemmanager CAx, HAIDLMAIR GmbH
Production: NX10.0.3, VERICUT 8.0, FBM, MRL 3.1.4 | TcUA 10.1 MP7 Patch 0 ( | TcVis 10.1
Development: VB.NET, Tcl/Tk    Testing: NX11.0 EAP, NX12.0 EAP

How to Get the Most from Your Signature in the Community

Re: Expressions in CAM

Ken, I understood you were not a Siemens employee. I've heard of Moog. I was hoping that if Siemens was thinking about it then hopefully they would commit to it sometime in the feature. Maybe I got too excited. I have yet to see one of my ER's become a reality.

Using NX

Re: Expressions in CAM



In my opinion, it would be time to get the in the machine registered holding system as global variable. The user must specify the same selection criteria for each tool request. The method to solve this exclusively via the DEF file is long out of date.


Example for holding system:



With every tool-request the user has to select the holding system. We are working every time with a machine-setup. There the holding-system is known. This holding-system should be the default for the selection. By working with the DEF-File and without an expression or an environment-variable this is not possible.


The same topic is for the used material, that we also use for selection of the tools. In every tool-request the user has to select the material, which actually is known in part-material:



In the moment it looks like this (sorry, it's in German):



Best Regards




Learn online

Solution Information