Turning - Lead In and Lead Out Problems

[Anonymous]

Hi.  I need help with Lead In and Lead Out.  Please see the attached files.  There are two operations: Face and Profile.  The Facing operation faces the part and that is OK.  Then, the Profile operations comes in and wants to face the part AGAIN.  What I really want to do on the entry of the Profile is to just extend the chamfer but I can't seem to find anyway to get Fusion360 to do that.  I've tried drawing a 2D profile - no good.  I've also tried creating a second body to "extend" the chamfer and selecting it for confinement - still no good.  Hopefully, I'm just being stupid and somebody can help me out with this.  Thanks!

[ivan.stanojevic]

Hi,

You might want to try with changing the inner radius.

Hope this will help.

[Anonymous]

Hello Ivan - what I'd really like to have is more control over the lead-in and lead-out.  This is very much the standard in turning CAM packages.  I'm going to attach some screen shots from a different CAM package.  I appreciate how Fusion360 is trying to automate the process, but in turning it is often necessary to just draw geometry and have the tool follow it (rather than base everything on the model).  For instance, in many cases, you have to turn past the part to prepare the component for the parting tool. You also want to make sure the tool path doesn't start on the part - in this case I extended the chamfer to make sure the tool is away from the part when it begins the cut.  In Fusion360, I just can't find a way to do something like that.  

[ivan.stanojevic]

If you want to turn past the part you can use backside stock offset in confinement settings.

As for the lead in/out, you can try with the lead in/out extensions in order to get tool-path away from the part geometry.
However, I do agree that there is a room for improvements in turning and the development team is working on it.

[Anonymous]

Hello Ivan - thank you for your suggestions.  Increasing Back Side Stock Offset does let me drive the tool past the part.  Interestingly, I've discovered that Fusion360 reacts in an odd way if I use 90° as the lead out angle - I have to use 89.99° to get an exit move that is perpendicular to the OD of the part.  Unfortunately, nothing I do seems to work for the front of the part.  Rather than extend the move during the chamfer, Fusion360 is trying to perform a small facing move.  I've tried to use the lead in extension value, but it doesn't work.  I've even tried to create a second body and use it as a confinement surface, but that doesn't work either.  I wish I could just draw a line and have the tool follow it.

I really like Fusion360.  I've found the 3-axis milling  to be great and I believe it works really well.  However, in my opinion, the turning module needs some work.

Thanks,

-Franco

[Laurens-3DTechDraw]

Turning needs some love but this request I'm not sure what the gains are.

Are you compensating for other variables not being correct? Like tool offsets in the machine for example?

Pretty sure you can drive the turning paths now with a sketch right?

I think a tangential extension value could work but not sure what the development guys think of that.

[Lonnie.Cady]

@Anonymous that is because "extensions" are not what they sound like.  I originally thought they worked as you are wanting but they don't .  I have asked for years to have some tangential extensions for exactly what you are trying to accomplish.  They also work well for leading off on to grind stock.

Also I think you may be using the confinement incorrectly.  That is not this issue in this case but there is not need to select all the faces you want to machine.  Just the face/edge of the +Z end and the -Z end.  So only 2 selections are needed.

[Anonymous]

Hi - thanks for replying.  Hopefully, the Autodesk people will be watching this and it will get their attention.  Every other CAM system I've ever used allows you to tangentially extend  the lead in/out geometry.  Without that feature, the turning portion of Fusion360 is very weak (IMO) and it's usefulness is greatly diminished.  I was getting crazy with the confinement surfaces because I was trying to force the software to do what I wanted it to do.

Thanks,

-Franco

[Anonymous]

Hi.  I tried creating a sketch, but I have the same problem - there just doesn't seem to be any way to tangentially extend the move into the chamfer.  

Machine offsets are manipulated differently on a lathe as compared to a milling machine.  Operators are constantly moving the X or Z position to control dimensions on a tool by tool basis.  You must provide them with tool paths that will accommodate these adjustments.

Having the ability to control the lead in and lead out is 100% essential, especially when programming a lathe.  In this example, you would never want to touch the face (after it has already been faced in the previous operation) and then roll around to the chamfer - that would leave a strange witness mark on the part.   In situations where you must "blend" one tool path into another on the same surface, (like a re chuck move on a twin spindle or a Swiss) on you need the ability to program a nice big radius that allows you to "sweep" into the surface and minimize the transition.  

Thanks,

-Franco

[Lonnie.Cady]

@Anonymous you wont get any arguments from me.  Pretty much my sentiments exactly.  But I would point out that it has been like this for probably over 4years.  I have asked numerous times along with others and put it in the idea station.  I am not sure the development team or ADSK seems to see as much value in it.  They have implemented things that seem more complex like no drag turning and sub spindle hand off. So it is not something I see happening soon.

The latest release of leadin seems slightly worse and I think there are new issues introduced in this release.

IMO lead and tangential extensions should be a bullet proof part of the tool paths.  Why keep adding more when the basic control is not there yet.

[Anonymous]

It seems as though they are trying to automate too much of the process.  Sometimes, you just need to draw geometry and have the tool follow it - end of story.  If the developers could facilitate that as well as proper control of the lead-in and lead-out move, then Fusion360 Turning would be much more useful.  

If they could just make a few improvements to Turning, I think they'd be surprised at how many new users they gain.  Many CNC programmers who work with Lathes don't need anything more than the basics - but it has to work well and be easy to use.  

I'm going to end this on a positive note.  I really like Fusion360.  It has been a total game changer and I really appreciate what Autodesk is doing with the product.  Milling works great and I love it.  I'll keep my hopes up that the developers will someday make changes to turning.

Thanks,

-Franco