topic Re: Turning - Independent Plunge and Turn Feedrate in Fusion Manufacture Forum

Turning - Independent Plunge and Turn Feedrate

timdrink01 — Tue, 13 Dec 2016 16:45:59 GMT

I'm working on a part with a 1.918" wide full radius groove. Using a 1/4" Manchester/Widia full radius grooving tool. Stock is 12" OD.

Using "sideways with partial stepdown" grooving pattern. I did a smaller grooved part and it works great. However I'm being feed limited by the plunge. By the Manchester book they want the plunge at .003-.005 IPR and the feed at .007-.020 IPR". I'm currently running both at .010 IPR, the plunge doesn't like it but has held up so far.

I thought that the "Use reduced feedrate" would be the ticket but it doesn't seem to use that value with the "sideways with partial stepdown" grooving pattern. Maybe that's a post issue? When I switched grooving pattern to "Partial Stepdown" it did use the "Use reduced feedrate" value.

Is it a post issue? A bug? Or possible just not the intended usage?

Re: Turning - Independent Plunge and Turn Feedrate

timdrink01 — Tue, 13 Dec 2016 18:34:03 GMT

Well after looking at it a bit closer, due to the radius bottom, the tool is never taking a true plunge. It's an arcing plunge so to speak.

G0 Z-0.6433
G1 X11.68 F0.01
X11.62
X11.6 Z-0.6438
G2 X11.4 Z-0.6594 R0.797 -- start reduced feedrate here
G1 Z-2.2156  -- return to normal feedrate here
G2 X11.6 Z-2.2312 R0.797
G1 X11.6141 Z-2.2241
X11.68
G0 Z-0.6574

In reality I'd be happy if I could just get the linear Z feed at the normal feedrate and all the rest could be at the reduced feedrate. It seems like that way be an easier mod.

I've found in the post where it references reducedFeedrate but can't seem to decipher where when/how it uses it.

Re: Turning - Independent Plunge and Turn Feedrate

Steinwerks — Tue, 13 Dec 2016 19:26:01 GMT

reducedFeedrate is only output in the Part-off toolpath. AFAIK you would need to perform some logic post gymnastics to get differing feedrates in a single toolpath like this, but you can also head over here and start an Idea and see how much support there is for that functionality: http://forums.autodesk.com/t5/hsm-ideas/idb-p/231/tab/most-recent

Re: Turning - Independent Plunge and Turn Feedrate

timdrink01 — Tue, 13 Dec 2016 19:36:25 GMT

If I duplicate grooving operation and change the grooving pattern from "sideways with partial stepdown" to "full stepdown" I get the code below. Cutting feed per rev is set to .010" and reduced feed is set to .008".

G0 Z-0.5701
X12.16
G1 X12. F0.01
X11.9887 F0.008
X12. F0.01
X12.16
G0 Z-0.6818
G1 X12. F0.01
X11.2386 F0.008
X11.9911 F0.01
X12.
X12.1487
G0 X12.16
Z-0.7934

So it certainly seems to be using the value in the groove dialog box, maybe it has a different variable name?

Re: Turning - Independent Plunge and Turn Feedrate

timdrink01 — Tue, 13 Dec 2016 21:05:06 GMT

I've done a bit more trial and error. If I change the groove to have straight walls, the reduced feed shows up. I also set the lead in feed to .005 and lead out to .006 to see if those would help but no luck.

G0 Z-0.6322 (the first two roughing passes roll around the outside corner and have a plunging arc)
X12.092
G1 X11.88 F0.01
X11.8194 F0.005 (lead in feedrate)
X11.8 Z-0.6346
G3 X11.7126 Z-0.6405 R0.165 F0.01 (plunging arc, due to cutter comp?)
G1 X11.6 (straight plunge cut)
Z-2.2345
X11.7126
G3 X11.8 Z-2.2404 R0.165
G1 X11.8141 Z-2.2333 F0.006 (lead out feedrate)
X11.88

G0 Z-0.6405 (first roughing pass that doesn't roll into the cut)
G1 X11.68 F0.01 
X11.6 F0.005 (lead in)
X11.4 F0.008 (straight plunge)
Z-2.2345 F0.01
X11.6
X11.6141 Z-2.2274 F0.006
X11.68
G0 Z-0.6405

Watching the videos on post editing, hoping it helps me to better wrap my head around it.

Re: Turning - Independent Plunge and Turn Feedrate

Steinwerks — Tue, 13 Dec 2016 21:56:56 GMT

Interesting. I presume that's because the groove toolpath can be used as a parting toolpath also, and you are correct the box is in the Passes tab.

The tooltip does say that it is in the X direction.

I will see what I can find out about how it is applied, although it doesn't seem to affect a grooving operation. The Parting operation has a specific radius to which it is applied.

Edit: okay I can see it now, I believe it must use multiple passes, and the walls need not be straight:

Re: Turning - Independent Plunge and Turn Feedrate

timdrink01 — Tue, 13 Dec 2016 22:23:04 GMT

Excellent, that looks promising. Where do you find that handy looking toolpath - moves screen?

Re: Turning - Independent Plunge and Turn Feedrate

Steinwerks — Tue, 13 Dec 2016 22:41:46 GMT

If you click the little expansion arrow next to the toolpath, right-click on the toolpath size (it'll be in Kb) and select View Toolpath. You can't rotate the view at all while this is up but it will do sort of a live backplot as you select points on the list and it can be very handy for obvious reasons.

Re: Turning - Independent Plunge and Turn Feedrate

timdrink01 — Wed, 14 Dec 2016 13:10:42 GMT

I think my issue is still with the radius moves. The reduced feed only applies to linear x axis moves. Need to get the machine up and running this morning so I'll modify the code by hand but I have about a dozen variants of this part so I'll keep digging into the post and see if I can wrap my head around it. This is the version of the part that I modified to have a section of straight walls. The real part is a full radius and as such there's never a straight x axis cutting move.

Re: Turning - Independent Plunge and Turn Feedrate

Steinwerks — Wed, 14 Dec 2016 14:15:49 GMT

I think your only workaround for now may be to limit the roughing feed. You could modify the post to output something based on the direction of travel but that would introduce a whole new section with logic built in to recognize it.

If you use the dump.cps post you will see where the CAM is outputting the reduced feedrate, but it is passed through the CAM at the travel locations:

368: onMovement(MOVEMENT_LEAD_IN /*lead in*/)
368: onLinear(0.47501533988892564, 0, -1.0230283662090152, 0.01000000031914298)
369: onMovement(MOVEMENT_REDUCED /*reduced*/)
369: onLinear(0.4740073361734706, 0, -1.0230283662090152, 0.002500000079785745)
370: onMovement(MOVEMENT_LINK_DIRECT /*direct*/)
370: onLinear(0.47499172330841305, 0, -1.0230283662090152, 0.01000000031914298)
371: onMovement(MOVEMENT_LEAD_OUT /*lead out*/)
371: onLinear(0.47501533988892564, 0, -1.0230283662090152, 0.01000000031914298)
372: onMovement(MOVEMENT_LINK_DIRECT /*direct*/)
372: onLinear(0.5550157366775152, 0, -1.0230283662090152, 0.01000000031914298)
373: onMovement(MOVEMENT_RAPID /*rapid*/)
373: onRapid(0.5550157366775152, 0, -1.0620267372431718)
374: onMovement(MOVEMENT_LEAD_IN /*lead in*/)
374: onLinear(0.47501533988892564, 0, -1.0620267372431718, 0.01000000031914298)
375: onMovement(MOVEMENT_REDUCED /*reduced*/)
375: onLinear(0.45274253905288814, 0, -1.0620267372431718, 0.002500000079785745)
376: onMovement(MOVEMENT_LINK_DIRECT /*direct*/)

Re: Turning - Independent Plunge and Turn Feedrate

Anonymous — Thu, 15 Dec 2016 06:17:02 GMT

Ok, I played around with the reduced feedrate to implement a work around probably last year sometime (before it worked at all). I think some of my changes should apply here. I just did a minor change and quick test and it appears to work.

Assumptions made here: (1) You want the reduced feed rate on cutting (roughing) but not finishing passes. (2) My understanding is the main issue is reducing the feed rate for circular cuts.

First you need to created a variable to act as a flag for when to do the alternate feed processing. There should be a list of variables towards the top (line 94 on the post I'm looking at) starts with the comment // fixed settings. We need to add the reducedGrooveFeed line.

// fixed settings
var firstFeedParameter = 500;
var gotSecondarySpindle = true;
var gotPartCatcher = false;

// Add this one:
var reduceGrooveFeed = false;

Make sure you don't already have an onMovement function. If you do we'll have to look at modifying it. If not, just add this:

function onMovement(type) {

  if (type == MOVEMENT_CUTTING) {   // don't reduce feed rate for finish passes || type == 14 /*finishing?*/ ) {            
    reduceGrooveFeed = true;    
  }
  else {
    reduceGrooveFeed = false;
  }
}

So that sets the flag we created earlier to true if the movement is Cutting or Finishing. We don't care about Reduced because those On_Linear calls should already be passed the correct feedrate.

OnLinear and OnCircular are passed a feed rate parameter. However, each of those functions calls getFeed to format that number into an "Fxxx.xx" string. ~~So we can modify GetFeed to take care of the various places the feedrate is used instead of changing all of those places individually.~~

The code we need to add is this:

  // Work around for grooving w/reduced circular feed rates
  if (hasParameter("operation:useReducedFeed") && reduceGrooveFeed) {
    return feedOutput.format(getParameter("operation:reducedFeedrateValue"));
  }

So if reducedGrooveFeed has been set true by OnMovement because its Cutting or Finishing this code will cause it to use the reducedFeedrateValue instead of the original.

Ok... I tested that and changed my mind. Like I said, GetFeed is called for all moves. If we only want to affect roughing circular moves, better to put code in the OnCircular function only. Otherwise you could affect Z axis moves unless you test for what axis changed...

So add the following to onCircular:

  // Work around for grooving w/reduced circular feed rates
  if (hasParameter("operation:useReducedFeed") && reduceGrooveFeed) {
    feed = getParameter("operation:reducedFeedrateValue");
  }

I just put it toward the top before the line that says "var start = getCurrentPosition();"

So this code will just throw out whatever feed was passed into onCircular and replace it with the reduced feedrate. Seems to work correctly in my (very limited) testing.

Make sure you check the code well before you try and run it. It should only make changes to circular non-roughing passes when the useReduced checkbox is selected.

Let me know if this works... doesn't work... or at least get's you part of the way there.

Dave