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Need a better understanding of FBM and FBM author

Phenom
Phenom

Short background: we do a lot of one-off parts, including complex parts with high tolerance 3D surfaces. On the other hand, there's also a lot of fairly simple prismatic machining. Machines are currently 3-ax only.

 

We do everything manually, because we haven't got FBM to work properly. Ok, we do use a master file, from which we copy/paste operations for added speed, but I still feel we're wasting a lot of time doing repetitive programming.

 

Am I correct in assuming the basic CAM Express license doesn't really work for FBM? The created operations (when they happen to work) are pretty crude and only pick imaginary tools from the NX built-in sample library. Would I need the FBM author license to make any real use of this functionality? 

 

One specific need would be to efficiently create toolpaths for threaded holes. This is still my most dreaded task; every part has umpteen holes of various size and nature and NX has the tendency to randomly assume I want to machine from the underside. In addition, our models  rarely have modeled threads or chamfers, but some do. For the life of me, I can't create toolpaths for these without pulling some of my already receding hair out.

 

The other problem is using form taps. The drill is oversized (compared to the one on the model) and NX gives us uphill all the way.

 

For the threaded holes I'd be happy with a crappy old-school approach: a set of three operations with pre-defined depths (say 12mm deep 3.7mm drilled hole, countersink 2.2mm deep and tap to 10mm depth) Then just point and shoot. Unless, of course, I could get the automation to work Smiley Wink

 

Any pointers would be greatly appreciated and I'll be more than happy to give more info if someone cares to help. If this is just an "idiot user" case, we'll be happy to pay our VAR to get ourselves re-programmed. If it means getting FBM author, we'll have to give it some thought.

 

Thanks for surviving the long rant!

 

Harri

5 REPLIES 5

Re: Need a better understanding of FBM and FBM author

Solution Partner Genius Solution Partner Genius
Solution Partner Genius

Harri:

 

It's not so much that the CAM Express license doesn't work with FBM, but that the OOTB FBM rules are not specific to your manufacturing needs.   I consider the OOTB FBM to be useful for demonstrating the capabilities of NX FBM, but not actually suitable for production purposes.  I've implemented FBM at numerous clients here in Canada, and in all cases, the FBM rules had to be customized for each site.

 

Once you have FBM running the way you need, the pay-back wrt to increased productivity is phenominal.  If a company is serious about implementing FBM, I strongly recommend that someone from that company learn how to customize and maintain FBM - especially if using an outside service to help them develop and implement FBM - that way the company (i.e., you) can maintain and continue to develop/enhance their implementation as required.

 

One thing to bear in mind, is that FBM requires a tooling library, so if you do not currently use/have a customized tool library, that will be one of the things you will have to develop as part of your FBM implementation.

 

There is a PDF document that gets loaded with FBM (not sure if this gets installed with CAM Express) but check in your NX install   ...\MACH\machining_knowledge_editor\bin\English\Help folder - in there is a file called MachiningKnowledgeEditor.pdf which is a user training manual.

 

So definitely use your VAR to help you get things going, but also get training on FBM so that you can take over the project in the long run.

 

Regards,

~Ulas

 

Re: Need a better understanding of FBM and FBM author

Phenom
Phenom

Thank you @Ulas for taking the time to reply in such detail. Exactly what I was hoping to hear. I'll read the documentation and have already scheduled a meeting with our VAR. 

 

If I can pick your brain a little more, what (if any) are the limitations and downsides for practical work?

 

/Harri

 

Re: Need a better understanding of FBM and FBM author

Solution Partner Genius Solution Partner Genius
Solution Partner Genius

Harri:

 

Personnally, I don't believe there to be any down-sides to NX FBM - more like caveats or things to be aware of - as I don't know your VAR's experience with FBM, here are some general things to consider:

 

  • Don't try to implement every possible feature you need to machine in one shot - start with simple cases and work your way up through the different features you want to machine.
  • Don't work in an actual part file/job while developing your rules - there's too much other "stuff" going on in an actual part file that will make it difficult to develop/test/debug a machining rule - always create a simple block with either a single feature or a range of sizes of the same feature.
  • If you haven't already done so, you may also want to consider implementing the feeds/speeds library for use with your FBM rules (this is not absolutely necessary, but it means that you don't have to worry about feeds/speeds when creating your machining rules).
  • Manage expectations, both of the users and management - this will not be a 1-day or 1-week undertaking - it requires planning and work - but the benefits (I believe) will be enormous.
  • Don't get hung up on how to machine features from two sides.  Instead, set up a process for the users where it's understood that one set of rules (e.g. Backside) must always be run first  (on the back-side of a part) - and your rules for this case will machine all holes/features that can be machined from this side.  Then have a second set of rules for machining the opposite side (e.g. Frontside etc.,) which assume that the back has already been machined and therefore only need to machine what's accessible from the front (or opposite side).
  • Learn how to develop/write rules using the MKE (Machining Knowledge Editor), but use Teach Operation Sets to actually create your initial rules which you can then edit/tweak/enhance the resulting rules with the MKE.  This can save you a lot of time developing rules for your features.
  • Create your own custom machining knowledge file from scratch - do not add your rules to the OOTB rules, or for that matter, don't try to adapt the OOTB machining knowledge to your needs.  The MK file that comes with NX has 100s of rules, many of which do not apply to your needs and working in this file will only become cumbersome over time.  Creating your own custom knowledge file not only makes it easier to maintain the file, but also simpler for your programmers to use.  Some of my clients have dozens of custom rule libraries - designed for specific types of work/jobs.
  • Also (based on the previous point), don't try to develop a single rule library to handle every possible feature and machining case - if its easier to create a another library to handle something - do that.
  • FBM uses a template part with different machining operations in it - take advantage of this and consider creating you own customized template(s) based on the OOTB template part that have been configured specifically to your machining setups/requirements.
  • You can include non-FBM operations (i.e., interactive milling ops) as part of your FBM template part/setup - you're not just limited to using "FBM" operations in a setup.
  • One of the challenges to a successful implementation is in determining what rules should be applied to a feature - in other words, how do you tell if a simple through-hole (STEP1HOLE) is a clearance hole, or a dowel hole, or a tapped hole (assuming that it doesn't have a symbolic thread attached to it), or some other special function hole?  This is what you need to figure out before hand - are you going to use attributes, hole type and hole size, color, or a combination of all of these.
  • I also recommend mapping the OOTB features (e.g. STEP1HOLE, STEP2POCKET, etc.) to your own feature names (e.g. ClearanceHole, TopDowelHole, FCS_Register, etc.) - this makes it easier when defining rules for a particular feature as well as making the resulting feature names more user-friendly.
  • Finally, this will be a learning process for you, so expect to make mistakes and trip-up every now and then - but trust me, in the end, the effort will be well worth it!

 

Now, when it comes to limitations, not to sound trite, but it's really up to your imagination.  I mean, yes, there are actual limitations, but with some creativity, it is quite amazing as to what can be done.

 

 

Regards,

~Ulas

 

Re: Need a better understanding of FBM and FBM author

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

Related to the licenses, CAM Express is not the problem, since it is a regular NX installation.

What licenses do you need:

  • to use/execute FBM
    • ug_holemaking
      • contained in all recent NX CAM bundles
      • for NX11430 you need NX30432, the 2.5D add-on
  • to change the manufacturing rules inside of MKE
    • fbm_author ... NX30435

In general it is best to start from scratch, since the machining rules shipping with NX are demonstrating all possibilities.

A simple set of rules build by your own is much easier to understand and maintain.

Stefan Pendl, Systemmanager CAx, HAIDLMAIR GmbH
Production: NX10.0.3, VERICUT 8.2, FBM, MRL 3.1.7 | TcUA 10.1 MP7 Patch 0 (10.1.7.0) | TcVis 11.4
Development: C (ITK), .NET, Tcl/Tk Testing: NX12.0 | AWC 3.4 Preparing: NX12.0

Employees of the customers, together we are strong Smiley Wink
How to Get the Most from Your Signature in the Community
NX Customization - Best Practice Guide

Re: Need a better understanding of FBM and FBM author

Phenom
Phenom

Thanks @Stefan_Pendl , we currently have NX31433 CAM Express 3 Axis Milling Add-on licenses, but might be going to 5-ax or even total machining, which includes FBM MKE. I'll start with the simple rules as you suggetsed and build up from there.

 

/Harri

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