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Vertical arc output.

Pioneer
Pioneer

I have a post related question but I thought it might be better asked here why you're doing it one way or the other.  Does everyone have their posts setup to output linear moves on vertical arcs and if not, why?  I've attached a pic of a particular Floor Wall toolpath as an example. The question I have about this one is with the options you have for the Engage Type (Helical, Ramp On Shape, Plunge) how would Cutter Comp be turned on using the Minimum Move if you were outputting vertical arcs since there's no horizontal arc option for the Engage Type which the Minimum Move option would add a linear move to so that comp would be turned on?  Would it throw in a linear move to turn on comp before or after the vertical arc?  With Helical and Ramp On Shape the comp is turned on during any linear move that's either 2D or even 3D evidentally if you're setup to output linear moves only.  I obviously have the Smoothing Radius turned on for the Transfer/Rapid moves too.  Would those stay linear moves with vertical arcs enabled in your post or would they be turned in to vertical arcs too?

 

I learned years ago with other software that if you're not running a dinosaur of a CNC machine that has the throughput to run whatever linear code you throw at it you're best to avoid vertical arcs altogether and that they’ll do more harm than good. I’ve never really dealt with vertical arcs (XZ or YZ axis) and turning cutter comp on for your XY axis at the same time before though.

 

TIA!!!

 

Capture.JPG

 

 

6 REPLIES 6

Re: Vertical arc output.

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

hi,

 

maybe not a answer but:

 

1.In your picture I think the arc is not generated in any of planes XY,XZ, YZ = no circular output.

2. Also these rapid smooth path is not created as arc at all, but lines. It is designed like that = no circular output.

 

Even if you created rapid smooth "arc" in correct plane, there will be no output because of 2.

 

To understand it better on example:

I prepared tool path in plane XZ, smooth radius on rapids turned on, turn on arc per/par to tool axis in the operation

here is the result:

engage - created as a circle Smiley Happy

 rapid arc - linear gotos Smiley Sad

aa.JPG

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#♫ PB, 5ax, itnc, nx, vericut ♫ #

Re: Vertical arc output.

A long time ago, when raster cutting in the principle planes was common, I experimented with XZ and YZ arcs but did not spend much time on it.  Software was becoming better at 3D cutting and machines were handling small G1 moves better too.  Typically I use smooth NCM's for all my 3D cutting so then I use high feed G1 positioning on those paths but I still use some simple arc engages for some other operations.  For me my objective is for a balance of the type the parts, operations, machines used and  standardizing/automating as much as my work flow as reasonbly possible.  Thankfully NX is very flexible and extensible. 

 

The image is showing a flow cutting reference tool operation and in this case the positioning is fairly decent but I would like to see it enhanced to use shortest possible positioning over peaks. For example, using more straight moves than large arc moves to get over peaks.  I have suggested this in EAP feedback for Flow Milling but have not submitted a formal ER.

  Image 1.png

NX 12.0.2

Re: Vertical arc output.

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

While I enable them in my posts, the place I think vertical are most useful is machining with a ball mill, perpendicular to the axis of revolution of a revolved surface (cylinder/cone/torus/etc.)

- much smoother face results 

- much smaller toolpath.

The only issue is that Siemens seems to periodically "break" this output (sigh...)

 

If you are doing a free-form surface, I don't think arcs buy you much (if anything)...

Ken Akerboom Sr CAx Systems Engr, Moog, Inc.
Production: NX10.0.3.5 MP16/TC11.2
I'd rather be e-steamed than e-diseaseled


Re: Vertical arc output.

Pioneer
Pioneer

"Typically I use smooth NCM's for all my 3D cutting so then I use high feed G1 positioning on those paths"

 

As opposed to G0 moves?  What does high feed G1 positioning give you with smooth NCM's over regular G0?

Re: Vertical arc output.

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

*from what I've been told* (I don't have any direct experience with this)

Using the smooth motions (G1 moves without sharp angles between them, at a high feed rate) allows the machine axes to stay moving fast.

If you use G0, or right-angle changes in direction, the machine has to decel / accel (which slows things down).

 

Note if you actually output G2/G3 (arc) (again, from what I've inferred) the machine has to transition out of the high-speed machining mode for the arc, then start it up again.  

 

Note this may apply more to newer machines where the G1 max feedrate (more or less) the same as the G0 "feedrate"

Ken Akerboom Sr CAx Systems Engr, Moog, Inc.
Production: NX10.0.3.5 MP16/TC11.2
I'd rather be e-steamed than e-diseaseled


Re: Vertical arc output.

High feed G01 positioning will make for smooth machine positioning when using  Smoothing for Transfer/Rapid movements.  If your machine does not have a high max feed rate then you might want to stay clear of G01 positioning and Smooth Tranfers.  You can also use G01 positioning if your machine is not capable of linear positioning.  I noticied from your image you had smooth tranfers enabled and the dashed transfers identifies them as G00 movements whereas a solid move is controlled by a feed rate.  You can perform a quick A-B comparison; run programs with G00 smooth tranfers and another program with G01 transfers.  Your machine might dance across the floor from pounding when it tries to run all those tiny G00 moves.  Machines will handle it differently; some will pound into oblivion others may not at all. 

 

Ken A. explains it better as to what causes the behavior. 

NX 12.0.2

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