4th axis zero at program start / post issue ?

[Chris Rizzo]

4th axis rookie here...

 

How do I force my forth axis to present the proper plane at the program beginning?

[gcode]

I usually make the center of the rotary axis program zero. I'm assuming your rotary table is

rotating about the X axis.

Top plane will be A0

If you need a different angle, rotate TOP about the X axis, save it and use the new work plane

as a Tool and Constuction plane.

A180 is not BOTTOM, you need to rotate TOP 180 about X for that.

All the 5 axis toolpaths work very well for rotary work if yu change them to 4 axis on the geometry page

[Chris Rizzo]

Thx gcode,

 

I've got my center at z0, and I've got basically a two sided part. A0. and A180. Using 4th as an indexer.

 

First operation I'm running in t-plane 1, and then tranforming / rotating by tool plane 180 degrees. Works fine if my machine is already in A0.

 

Basically, I'm not getting an A0. at the beginning of my program.

[gcode]

Make sure you have the T/C Plane checked and set to TOP plane for the first toolpath. If that doesn't give you an A0, you may have a post issue.

Check you email, I sent you a sample file.

 

edit.. I played with this a little. If your first toolpath is on TOP plane, the post doesn't know its a rotary move.

Make sure Tool plane and CPlane are set to TOP

Open Rotary Axis and set Rotation Type to

Rotary Axis positioning and Rotate about X.

This will force the A0 output

 

[ 05-06-2005, 12:50 AM: Message edited by: gcode ]

[mcpgmr]

Not sure if anyone else is doing this but it works good for me. Toolpaths/next menu/point goto xyz, pick a predetermined point in space at a safe clear plane for you rotary setup. Set the T/C plane to (1 Top) (A0.0) if that's the desired position you want to end up at. Pick the last tool used just for the sake of needing a tool in the operation. HTH !

[cblythe3d]

Read the writing on the wall. Create drafting note is my secret for perfect positioning every time providing your post is setup correctly.

.

If you rotate your part or g-view to each position you want to cut the text of a note on that plane better be right side up and not backwards.

Cplane/Tplane = entity (the note)

 

Works on 4 and 5 axis positioning without fail

 

Charle

--------------------------------

Remember if you mirror both X and Y axis it is the same as a 180 deg rotation.

[Chris Rizzo]

Thx Gcode,

 

Ck your mail, too.

 

quote:

---

If your first toolpath is on TOP plane, the post doesn't know its a rotary move.

---

Makes total sense, however when I run MPfan or your post I WILL get an A0. call at the beginning. I will not get that when I run my post.

 

What I'm doing is running a transformed toolpath (rotate by view) with the source my defined WCS top plane, and the resultants rotated by t plane. So the source will not think it needs an A move, but the transformed ops will. However I am indeed getting an inital A move (contrary to what makes sense), with any post BUT mine.

 

Question 2-

 

I use WCS without a flaw for all my regular 3 axis multi-sideded parts, now getting into 4-axis I've got all sorts of new self-inflicted issues. Seems I'm having A axis orientations determined by system view 1, where as I prefered to use a defined WCS for part orientations calling all machined faces (c/t/g views) top top top.

 

I'm basically transfering parts that were once multi flips in vices, with each side defined as a top, now to a 4th axis. Do I have to go back and strip the WCS top/top/top/ info and transfer everything to C/T plane call-outs based on system view 1?

 

hope you can follow all that

[John Summers]

All variables (including A) are initialized at zero. If the first A move is zero, it will not output if A is modal. Try setting prv_a=999 in PSOF, or make A non-modal (add 'n' to A's FS).

[crazy^millman]

Yeah I find WCS problematic at time for 4th axis and 5th axis work. I stay with the 1 and use my c-planes from there. If you had WCS I would delelte them all out and then move it to where you need and be done with it from there. If you have the WCS out the Toolpaths will most times need to be picked re check and doulbe checked to make sure you are getting what you are really after.

 

HTH

[Chris Rizzo]

Just like to give a big thanks to Gcode for helping me through my rotary woes. My older post needed a little help, and I needed a little tutorial.

 

[gcode]

[TheePres]

Yes,

GCode is the Man for 4th axis help....

Thanks for helping me also Gcode.

[Leon-ZA]

I have exactly the same problem, but i have no idea what all you guys just said here. I always keep my CP and TP the same.

 

And well... I added a A0. in my initialization move of my code ;P

 

But the fact that my POST did not add a A0. in my first move bothered me. Then I had a look further down and I saw that every time I indexed it used the next datum point. Like instead of just G54, it went on to use G55 G56 and G57 aswell. I was doing a 4 sided milling operation. These I also edited manually.

 

When I have a bit more experience with mAstercam I'll get into all this other funny stuff.

[Rob B]

cmr,

 

I will look into this. I had the same problem. If i'm not mistaken the advice given below was given to me by James in one of my previous post. My post will out put "A0" at the beginning of the operation. Let me know if this helps. What type of machine are you running.

 

Quote from James M.:

To force an axis to "show" itself. pfxout (X), pfyout(Y), pfzout(Z), and pfcout(Rotary Motion).

 

Change pcout to pfcout in the psof0, ptlchg, ptlchg0, and peof postblocks. (This goes for the posts on the Mastercam CD)