Turning back to front - bug??

[rob.blanch]

Just figuring out turning in manufacturing, playing with changing direction to back to front, and pretty sure I've found a bug.

So, very simple shape. I've got a custom cutting tool, which is angled with a flat face on one side, R1mm at the end, so that I can cut profiles and face off the part being cut. Because this is woodwork, I want to cut with the grain or downhill. If I create a finishing toolpath front to back, so cutting towards the chuck and going uphill - toolpath generates fine. If I try to do the other way, back to front, it doesnt generate a proper path.

However! If give it a turret angle of + or - 0.1 deg, it works fine. I wondered if fusion didnt like the flat end radius for some reason, so I tried a slight point on the end, rather than being fully rounded, but got the same result (not shown). It seems to be just very specifically a flat face, moving back to front, that it doesnt like. So, pretty sure this is a bug?!

[HughesTooling · Accepted solution]

The problem is you have no clearance behind the tip.

You need to set up something like this with custom setting. Note when you edit the holder it unhelpfully edits the tip. When you set the lead angel to zero it changes the tip to zero included angle for some reason. See attached file.

[rob.blanch]

Thank you!! I can work with that. Still a bit buggy of course, if anyone at Autodesk feels like fixing, but I can get on with it now. Much appreciated!

[HughesTooling]

@seth.madore  Looks like a couple of bugs?

First is if the lead angle on the tip is zero you get zero relief behind the tip.

If you use one of the built in option like -5° side or even a custom angle you get the trailing relief.

And then there's a bug where the tip is changed to zero included angle every time you edit the holder lead angle.

[seth.madore]

It does indeed look like something's going on. I'll try to look at this either this evening or tomorrow morning. Poke me again if I don't respond back in a reasonable timeframe 🙂

[rob.blanch]

Thanks guys! I noticed myself that roughing operations without leaving any stock showed the tool going inside the workpiece, but wasnt sure if I'd screwed something up... simulation works fine however, so I think it's just displaying badly, assuming I'm not missing something, so mentioning anyway.

[HughesTooling]

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@rob.blanch wrote:

assuming I'm not missing something, so mentioning anyway.

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What you're seeing is compensation for the tip radius. The toolpath is at the tangent point point.

[rob.blanch]

Ahh right, that makes sense, thanks!

[seth.madore]

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@HughesTooling wrote:

@seth.madore  Looks like a couple of bugs?

First is if the lead angle on the tip is zero you get zero relief behind the tip.

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Isn't this "working as intended" though? Zero relief from a zero tip-angle?

[HughesTooling]

The holders I've got similar to that have relief angles matching the tip. So 

Zero lead but relief behind the tip matches the tip.

And another example

Mark