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Multus Post help - How to force C axis to index when pocket millings along Z axis

I am currently building a post for a Okuma Multus B300 and I have ran into a roadblock on how to force the C axis to index. 

 

Here is some background info.....

  • The feature that I am trying to mill is 4 similar pockets, 1 in each quadrant of rotation (the picture attached is a front view about Z axis). 
  • Currently the post wants to index and maintain at C0 and mill each pocket using XYZ. So when it comes time to mill the pockets in quadrant 2 and 3, the tool path exceeds the X travel limits.
  • I currently have 3 linked post lathe turning, X and B axis milling, and Z axis milling.

So my question is, how do I force the C axis to index accordingly for each pocket while maintaining the XYZ milling. 

 

Thanks!

17 REPLIES
Solution
Solution
Accepted by topic author jason_vowels
‎08-26-2015 04:32 AM

Re: Multus Post help - How to force C axis to index when pocket millings along Z axis

If they are separate operations (ratherthan transformed ones that are linked together) Try the "Rotate" UDE.  The "sketch for XY axis limits" is another thing I'd suggest (so you can tell at programming time whether you can use G138 mode or if you need to use G137 mode)

See my post in the other thread (just made a couple minutes ago)

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: Multus Post help - How to force C axis to index when pocket millings along Z axis

Ken,

The "Rotate" ude worked great! Thanks a bunch!

Re: Multus Post help - How to force C axis to index when pocket millings along Z axis

Hi Jason,

 

Im currently working on a Okuma Multus u3000, its quite similar to your B300, turn-mill, the only difference is that the seccond chuck is not used for machining, but i hit a roadblock trying to develop a 5axis machine plus a 2 axis lathe. I am finding it too complex programing each of the scenarios and i read that you did it with 3 posts, a lathe, an X/B Mill and a Z Mill, that sounds much easyer.

 

So the question is, how does your post look like or what considerations and scenarios you took into account? How did the NX CAM setup looks like as well? Pictures would be awesome, i just need some sort of guidance on to what actually works for this type of machines and go with that guide.

 

Thanks in advance!

Re: Multus Post help - How to force C axis to index when pocket millings along Z axis

To answer in a general way

To have separate posts work together, you "link" them

Typically a mill post is the "master" post (but it doesn't have to be)

so...

1) Create your 3 posts

2) In the "master" post, go to "Program & Tool Path" -> Linked posts

3) Add each post.  Define the "HEAD" name appropriately (e.g. "TURN", "MILL_XZC", and "MILL")

4) In your part file, add the "Head" UDE appropriately.  This MUST be set/encountered OUTSIDE an operation.  Typically I add to "Machining Method view" methods:

- Add method object (e.g. "MILL_XZC_METHOD")

- Right-click on that method -> Object -> Start events

- Add "Head" UDE, set head name to "MILL_XZC" (or whatever you specified for the HEAD in the "linked posts" dialog)

5) Make sure the operations are inside the appropriate METHOD view object.  You might want to add a check in "start of path" to make sure the method parent (mom_oper_method) is not the top-level "METHOD" object.

 

Ken

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: Multus Post help - How to force C axis to index when pocket millings along Z axis

[ Edited ]

Thank you Ken, I am well aware of that so far, I've already managed to get the setup in NX with the Head function and linked the posts in the builder as well, that is not an issue and the turn post itself works fine so far.

 

What I'm getting stuck is creating the X and B axis milling post + the Z-axis mill, because using a 5-axis general post gives me a 5 axis motion and the machine we have is a 4+1 axis, the B axis is fixed (it positions itself to the tool axis orientation at first and then does the rest of the movements with 4 or 3 axis motions) and when I tried a 4-axis mill with table C on the XY plane to get the cross milling & drilling operations, it gives me an error. I haven't tryed using a 4-axis mill with B head, partly because I've got no idea how i'll add the C axis to be available for swarf operations where C rotates and Y-axis is fixed or to rotate C-axis for operations in a different "side".

C-Axis pocketC-Axis pocket

(C-axis rotates in a cross milling operation using the X or B axis)

Y-Axis pocketY-Axis pocket
(C- axis is fixed and XYZ movements are used in a cross milling operation using the X or B axis)

 

I started analyzing the SIM15 post and that might be the key, but it has way too many conditions that do not apply (no sync, no 2nd turret, no second turn spindle its just a tailstock that engages/disengages, plus a locked B head for most of the time) that setting them apart has been quite upsetting, there are no HEAD UDE used in that example.

 

The machine looks something like this:BC 4+1 AXIS MILL-TURN  + tailstockBC 4+1 AXIS MILL-TURN + tailstock

 

Re: Multus Post help - How to force C axis to index when pocket millings along Z axis

I am not familiar with this Okuma - but you will have to know exactly what is required in G code for the modes of postprocessor output you want. Does Okuma provide a G68.xx kind of rotation (my guess is yes - but by some macro call.) My first thought would be that you would want a head table 5 axis post for the most part - with a G69 rotate into frame ability. This is demonstrated in the SIM15 (how to do it.) It may be desirable to have some rules and preposition C (look at ROTATE ude code.) You will also need a XZC mode (from the sounds of it.) Does the Okuma support a G12.1 (or siemens TRANSMIT) style of at machine transformation? If so - that is just a 3 axis post mode then. Otherwise it is XZC style (post) which there is a template to create. The SIM15 example demonstrates my preferred style of post mode switching (on the fly with no head ude.) Keeping the posts separate (linked) is convenient in a lot of ways too - but I don't prefer it because each post has new formatting to keep up to date.

So - I guess my opinion on what "modes" the post needs is a 5 axis HT post with G68 style transformation (particularly if cycles or circles encountered) and an XZC or polar mode. I would provide a ude to switch between 5 axis HT - one selection with G68 and another without and an XZC mode.

NX10.03
Windows 7 Pro

Re: Multus Post help - How to force C axis to index when pocket millings along Z axis

On our Multus, the only place you can rotate the B axis is when it is at home - is that your issue?

 

I added procs to my "5 axis" (not XZC) mill post to check if the tool axis changes.

1) Make sure the B axis is rotated appropriately in initial / first move (make sure you are at home, then output the B rotation as needed)

2) Anywhere else, output a warning/error (or abort the post) if the B axis changes.

 

I did add some code that during a drill cycle, if the B rotates during a rapid move (NOT directly between cycles - it has to be a "legacy" PTP "Avoid" motion with G0 output) I go home, rotate the B, then re-approach (and output a warning to the NC programmer that they are responsible to avoid any crashes).

 

As needed, note they have G127 & G174 that can be used to rotate the CSYS (Like Fanuc G68)  (G126 / G175 to cancel)

 

Ken

 

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: Multus Post help - How to force C axis to index when pocket millings along Z axis

Hi Ken, that is exactly the case!!! 

 

Do you have a configuration of a 5 axis mill + lathe then? (thats what I´ve been trying so far)

What kind of procs did you add?

What criteria did you use to enable and disable the Y-axis? If its only a 5-axis machine im guessing that some operations need to use Polar motion (maybe), im thinking when the C axis is used for slots, Y-axis has to be locked as well here, did you set scenarios? like mom_coordinate_output_mode (I saw it on a SIM i cant recall, but it had a Cartesian XYZ , XZC Output, Axial Z PTP Cycles Polar XC and C-axis Mill Rotary Interpolate [for the last 2 im not sure in what operations can be used]) and used UDE to select one or the other.

 

If the reorientation of B-axis, which is actually the tool axis (I think), is done only and before the rest of the motion, the calculation of movements for the the rest of the axis does not include that of the B axis? or is there something else that needs to be done?

 

Does this type of machines need to unclamp/clamp the C-axis when it rotates to put the milling face normal to the tool-axis? The code thats been used- unclamps, rotates C and clamps-, but I'm thinking it doesnt have to because it doesnt do that when its using C as part of the movement. (Asking because i havent figured out when to call the clamp/unclamp when "needed")

 

What should I consider??? I know ive asked too many questions in one go... I'm sorry, I got excited and I'm just really stuck and lost with all the things to consider for this type of machine, I am still new to the post-builder and I still lack fundamental knowledge it seems, and probably CAM and machining theory as well.

 

Thanks for all the hints and help Ken!!! 

Re: Multus Post help - How to force C axis to index when pocket millings along Z axis

I have 3 posts -

1) General milling (5 axis)

2) XZC only mill

3) Lathe
I use HEAD UDE on Method view objects to select.

 

That way the post configuration does a lot of the work for me.

 

As far as procs I added - quite a lot.  I tend to use a "source"d in tcl file for all the tcl code I add (the PB_CMD_* routine just calls an external tcl proc in the sourced in files)

 

Ken

 

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


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