3D--I think?--CAM toolpath issues that are beyond me...

[johnhska8]

Hi all,

I've been to this forum before (and was helped enormously) but it's been a while and I'm afraid I'm back with some issues on how to generate sensible toolpaths for a new part.  I've provided a link to the file (I think correctly!) that I've started for this crazy thing.  This part requires the use of a 1/32"-dia ball ended end mill, which, please correct me if I'm wrong, but I believe it requires the use of 3D, not 2D, approaches, yes?  I've never yet done any 3D toolpaths, so I'm kind of lost I'm afraid.  I want to define the machining to just do the full depth of the cylindrical grooves 'in one pass', as they're not very deep and I believe the end mill can handle it (this is 6061 aluminum, by the way--).  I'm just not figuring out how to do that, and I'm also having a lousy time of simply defining workable tool paths, at all, for these three 'pieces' of the necessary milling process (that is, the big spiral; the 'entrance' grooves that intersect the spiral, and the 'exit' grooves that intersect the spiral--that's all there is...).  Any and all help here would be greatly appreciated, and I'll learn something valuable in the process, I am sure of that.  Thanks in advance--C. Hale, Lafayette CO 

https://a360.co/3wvETfo

[seth.madore]

How about a Spiral toolpath and a couple of 2D Contour toolpaths (with Patterns)?

 

File attached for your review 🙂

[johnhska8]

Hello Seth, and thanks!!  I poked around a bit further after sending my sad query, and did at least some of what you've done here; https://a360.co/3wvETfo updated some.  I do believe with your help above, I'll be able to get this whole toolpath.  In this updated version I just linked, I'm still having trouble with the 'intersections' that occur.  But surely your path you just provided will reveal the correct way to go here.  I've been thinking I ought to break the SW .prt file into like three separate files, which would probably 'solve' it (in a rather unsatisfying way), but no doubt what you show above will be truly the way to do it.  Thanks--this is truly an amazing forum, I got to say.  --Charley

[johnhska8]

Seth, wow, for such a seemingly dirt-simple program, there is a WEALTH of stuff there that you did that I'll be studying; "Pattern" is completely new to me; and a few other things you did.  Thanks, again, and I'll be looking at this hard over this weekend (and ideally actually make the crazy part, too!)  --Charley

[johnhska8]

Made the part!  I used Seth’s ops with one change, to do multiple depths of 0.01”, to try to lower the load a little on this quite tiny end mill; the mill was still there when it finished : )  the spiral had a considerable “scalloped” character to it, that would be nice to improve if I could.  The spiral op had the tolerance set to 0.0004”, and “Smoothing” wasn’t selected.  Would I benefit from selecting “Smoothing”?  Also set to 0.0004”?  Or…?  Thanks—

[johnhska8]

Hi all,

today I tried an experiment with smoothing selected in F360 for the spiral op on this part.  I just used the original part from yesterday, with the pretty irritating “scalloped” character in the spiral walls, and ran it again, this time full depth on all grooves (since nearly all the material is machined away at this point), spiral tolerance set at 0.0002”, and Smoothing set to the same, 0.0002” (default after changing tolerance to 0.0002”).  Took the feed rate up to 6 ipm, too.  It sounded like it was cutting, but, I see little difference in the “scalloping”.  Heck!

I should note this is a Tormach 770M, by the way.  I gather on the web that smoothing techniques vary a lot from machine to machine, machine software (PathPilot, here), etc.  Any thoughts on what I ought to do to get this spiral to be, well, smoother?  Thanks—

[johnhska8]

Here's a photo of what I got as described above (F360 CAM, spiral op, 0.0002" tolerance and 0.0002" smoothing, 10k RPM, 6 ipm feedrate, flood coolant; Tormach 770M, carbide 1/32" ball end mill, nearly zero (way sub-thou) TIR using brand new ER-32 collet).  I think there is basically no contribution of the 'scalloping' due to chatter or other machine/tool S&F issues; rather, I'm almost sure it's got to do with F360 CAM settings and/or Tormach770M/PathPilot limitations?  Anyone have any thoughts on how I'd get rid of this 'scalloped' character in the spiral groove?  Thanks--

[a.laasW8M6T]

Hey I had a look at the file and the spiral toolpath was generating pretty rough looking toolpath, smoothing wasn't helping but changing the Surface triangulation tolerance in the compare and edit menu tidied it up pretty good.

Compare and edit is found by right clicking on the toolpath.

Before

After

[johnhska8]

Oh wow, ok, so is that ever something I've never heard of, much less knew it existed!  "Compare and edit"--I'll sure have to read up on that.  Thanks much, it sure does appear to clean that behavior up big-time, as you describe.  I noted that the default appeared to be "Surface triangulation tolerance:  tolerance *0.5", as opposed to your change to "*0.02", got it.  Very interesting, to say the least.  I'll definitely try the part again with this setting.  Thanks!!

[HughesTooling]

Here's a way to make sure the spiral is dead flat. Create another body without the spiral, top of this part is a the depth of the spiral. See attached file.

I've selected the new body under Model and unselected the stock model. Like this you don't get all the interference meshing the spiral in the original body.

Mark

[johnhska8]

Wow, Mark, thanks for this addition. More F360 CAM stuff I do NOT know!  But this is a stellar way to learn more, and I appreciate it.  So are you saying that if I ran the part as it was previously (with the improved Surface Triangulation Tolerance value our other contributor suggested), it would still be a bit 'rough', due to some bobbling around in the z axis as it generates the spiral?  And your technique here prohibits the machine from doing that?  I'll have to really study this out fully and see if I can form any other worthwhile questions.  Thanks again, at any rate--I sure may try to go in the shop later today and actually run this and see what it looks like.  --Charley

[johnhska8]

OK actually, another quick question; did you have to go into "Design" versus "Manufacture" in F360, to add this Body aspect to the thing?  I've never yet done anything in "Design" to date, as I've got SolidWorks and some reasonable proficiency with it (and upload .prt files into F360 to do the CAM, etc.) and so haven't fiddled with F360 Design so far.  Anyhow, wondering about that.  thx--Charley

[johnhska8 · Accepted solution]

Well, you guys are da-bomb, that is for sure.  The combination of the Surface Triangulation Tolerance tweek, and the addition of a 2nd (yes?) Body that forces the toolpath to stay 'dead flat' in the spiral, resulted in this (see photo attached).  From my perspective it is now 'perfect'.  Thanks you guys--Charley 

[johnhska8]

Mark, is there any chance you might be able to spend a few minutes (I hope not more than that--) and sort of explain out your process above where you added the Body in Design mode to force the 'dead flat' tool path?  I think I could hopefully follow it by 'dissecting' your spiral op and I'm definitely planning to try to do that, but, I thought I'd ask if you could elaborate on it a bit in some 'how to' words/bullets?...thanks--Charley