Faceting and gouging in stock simulation and on part

[nicknsprecision]

I am running into this issue using 2D contour and 2D Bore mostly. I thought this was maybe an issue with the imported file at first but it is the same on any test part I make directly in fusion. There is gouging/faceting showing up in the bore faces and outer profiles of these family of parts. I have looked through the Smoothing section in the forums and used a variety of different smoothing options for 2D contour (not really anything for 2D Bore) nothing seems to change my simulations which end up showing up in my part. These seem to only happen on circular moves or anything non linear. Can anyone please help me with this!

Machine: Robodrill T14iA (Fanuc 16iM - HPCC (lookahead))

Regards, 

Nick

[LibertyMachine]

What post processor are you using? When it comes to the Simulation, consider that it's not a very good depiction of what you are actually going to encounter.

From some of your pictures, it looks more like chips are being recut and gouging the faces.

I do very fussy work in my shop, Fusion hasn't given me this issue yet, so lets see if we can nail down the cause..

[nicknsprecision]

@LibertyMachine Thanks for the quick reply mate.

I am in the shop now trying to troubleshoot.

I am using the following: 

FANUC Post 

"Optional Stop" off

"Preload tool" off

"use sequence numbers" off

I dont think it is chip re-cutting as I have pretty good chip management and coolant hitting the tool. Plus I would think I would have lines/gouging in these other areas (X/Y linear move) if it was that. And i am getting those small horizontal lines in my stock sim in my part which is what led me back to fusion just trying to figure out where this is coming from. This only really happens in combines XandY movements.

Regards, 

Nick

[HughesTooling]

Can you share any files, even mock something up with some ops setup how you normally set them. On a bore Fusion should just produce arc moves and if your control supports helical moves then helixes so a bit puzzled with the faceting there. 2d contour does have problems on external profiles if there are any splines. You should get better results with 3d contour or use cutter compensation in control if you want to stick with 2d.

Really need to see a part and your setting to help much more.

Mark

[nicknsprecision]

@HughesTooling I have attached the .f3d file in the initial post. If there is something else you need me to upload let me know. I will give 3D contour a try not and see if it makes any difference. 

Thanks 
Nick

[HughesTooling]

Not sure my eyes are good enough to spot any problems, didn't even see the file attached to the first post. 

How are you generating arcs? Are you using R or IJK, I prefer IJK as R is a bit vague. You can ignore the finish in the sim as speed of simulation will affect how it looks and which mode did you use, for me running a bit slower than default using standard mod seems better than your example.

The bore op is only producing circular moves so really shouldn't be a problem.

When I post this to my prototrak the bore is done with a single helical move.

N9 G00 X0.906 Y0.1787
N10 Z0.6
N11 G00 Z-0.4775
N12 G01 Z-0.5075 F30.
N13 X0.9063 Z-0.5131
N14 X0.9073 Z-0.5186
N15 X0.9088 Z-0.524
N16 X0.911 Z-0.5292
N17 X0.9137 Z-0.5341
N18 X0.9169 Z-0.5387
N19 X0.9207 Z-0.5429
N20 X0.9249 Z-0.5466
N21 X0.9294 Z-0.5498
N22 X0.9343 Z-0.5525
N23 X0.9395 Z-0.5547
N24 X0.9449 Z-0.5562
N25 X0.9504 Z-0.5572
N26 X0.956 Z-0.5575
N27 X0.981
N28 G03 X1.031 Y0.2287 I0. J0.05
N29 G07 X0.5816 Y-0.8467 Z-0.9512 I-1.5116 J0. D7.874 (helical move)
N30 X0.5816 Y-0.8467 I-1.0622 J1.0754 D1.
N31 G03 X0.582 Y-0.7761 I-0.0351 J0.0355
N32 G01 X0.5645 Y-0.7582
N33 X0.5606 Y-0.7543 Z-0.9509
N34 X0.5567 Y-0.7503 Z-0.9499
N35 X0.5529 Y-0.7465 Z-0.9484
N36 X0.5493 Y-0.7428 Z-0.9462
N37 X0.5458 Y-0.7393 Z-0.9435
N38 X0.5426 Y-0.7361 Z-0.9403
N39 X0.5397 Y-0.7331 Z-0.9366
N40 X0.537 Y-0.7304 Z-0.9324
N41 X0.5348 Y-0.7281 Z-0.9278
N42 X0.5329 Y-0.7262 Z-0.9229
N43 X0.5314 Y-0.7247 Z-0.9177
N44 X0.5303 Y-0.7236 Z-0.9123
N45 X0.5296 Y-0.7229 Z-0.9068
N46 X0.5294 Y-0.7227 Z-0.9012
N47 G00 Z0.6
N48 M334

Mark

[Anonymous]

Sorry,  I replied to wrong person by mistake.

Looking at your outside contour rough and finish strategy I notice something that I think may be the cause of your problem or at least contributing factor.

You are leaving .022 radial stock per surface in roughing then finishing in multiple Z levels.

Each time tool bytes into next level, tool gets loaded and causes deflection of part, tool or both, depending on stability, by however small amount, it matters. 

I would never do finish cut on turned surface in multiple Z lengths along shaft because result would be leaving steps at each break due to tool load at start of each cut causing deflection and vibration.

I think chips generated on next level are getting wiped around between flutes in arbitrary fashion and time intervals, gouging previously finished surface in upper level.

Tool may deflect as a result of chips interference then spring back and leave gouges in arbitrary places. 

I am surprised by the fact that there are no distinctive lines showing each level of finish pass. 

I would leave .01 radial stock in roughing, do one pass taking .008 across entire depth and follow with another pass of .002 and slower feed rate.

In this manor you would eliminate any deflection on second pass and establish uniform finish across entire depth of cut, using wear compensation to control size would be good idea too.

I glanced at some other parts and in one case you take 3/8" deep cuts with 1/4" diameter tool, that is a little too aggressive for my taste, if tool leaves inconsistent stock amount, finish pass will be effected by it.

[nicknsprecision]

@HughesTooling Thanks for the comprehensive/thorough reply on the boring operation. These are the settings I am using below. Is not using the the IJK messing this up?

I am using HPCC (high precision contour control) adding it in my code using G05 P10000 and G05 P0 to cancel as FANUC told me to do over the phone. It also looks like the post is outputing individual IJK moves? I dont know, I am very new to all this.

as follows:

Regards, 

Nick

[Anonymous]

Also, in anything I do, I,J,K is mandatory in all arc moves, R splits arcs over 90 degrees into quadrants, leaves tool marks and distorts arcs on lathe due to error margin allowance, I believe same is true on mill.

[nicknsprecision]

@Anonymous Inital boring op is leaving 0.022" specifically so I can run multiple boring opts for a spring pass at lighter load. (0.002" or less finish pass at a slower feed rate) this is not in the programming tree because I post is separately and use cutter comp. There are no tools 1/4" dia. other than the roughing operation going more than 1x diam. if you look at the 1/4" contouring there is 2 passes with a light pass left at ".150" stepdown. which is not 0.375" that your saying. 

For the ourside contour with the relieved 1/2" tool there are gouging in some areas and not if so why would this be?

[Anonymous]

I only took a closer look at rough and finish of outside contour, sorry if I missed something but then, you say you are using relieved end mill to finish outside contour, is that correct?

If so, I can see why you are finishing in levels but answer to that is end mill with flute length to capture entire depth of cut in one pass.

I think you would be much better off with two light finish passes, multiple Z levels finishing just beg for problems.

[Anonymous]

Another thing that comes to mind is tool run out, are you sure tool is not cutting with just one flute?

It would result in huge feed rate ratio per revolution as well as leaving gap between finish surface and working flute where chips can get trapped and cause problem like deflection and bouncing of tool back into the cut.

Also looking at some of the gouges in pictures, they seem to be taller then depth of cut in each level, leading me to believe that machine is having precision issue in executing tool path in same place on two different Z levels.

All this is just wild guess based on presented and partial information on my end, simple stuff tends to be overlooked sometimes.

[HughesTooling]

---

@Anonymous wrote:

Also, in anything I do, I,J,K is mandatory in all arc moves, R splits arcs over 90 degrees into quadrants, leaves tool marks and distorts arcs on lathe due to error margin allowance, I believe same is true on mill.

---

The force IJK is for non modal so you are OK, you're not using R. Looking a the bore code there is no problem there, your post is splitting the arcs into 180° moves and the coordinates are not wandering. You can see I is just swapping positive negative but the same all the way down and every other line matches, J is only output on the first helical move as it doesn't change.

I found a post in another thread where they were using G05 P0 for finishing cuts like 2d contour. Can you try the bore and finish cuts with G05 P0 to see if there's any difference?

Also you might want to download NC Corrector, looking at your finish toolpath from the top shows all levels are identical, You can zoom in real close and there are no signs the toolpath is wandering at all.

Mark

[Anonymous]

In my first few jobs years ago I learned that using R on lathe to cut arc that runs over 90 degree, code has to be broken in two lines at 90 degree mark or it results n ellipse. 

From that day on I always use IJK and use one sweep from start to finish of arc move on all lathe work. I only run mill work on mill-turns, only programmed few jobs for vertical mills here and there but whenever given choice I use IJK in software and post settings.

That does not fully ensure that machine will produce flawless result but its one factor I can control by choice.