Detect Undercut Stock

[JB7280]

Can anyone tell me what I'm missing here?  When I choose "detect undercut stock" the whole thing goes haywire.

 

I know the holder, and speeds and feeds aren't right.  Ignore that.  

 

 Operation 20 is the toolpath in question.  

 

https://drive.google.com/file/d/1HGUEcak81AX10rDAywKfnzjKNCpoDuKg/view?usp=drive_link

 

[JParis]

That's just letting you know that somewhere on the geometry there is a negative drafted face.....opti-rough can't undercut so it's just an alert

[JB7280]

3 hours ago, JParis said:

That's just letting you know that somewhere on the geometry there is a negative drafted face.....opti-rough can't undercut so it's just an alert

I'm not sure I follow.  It alerts you by slamming the tool through the part?  Or are you getting different results when you run it?

[JParis]

3 minutes ago, JB7280 said:

I'm not sure I follow.  It alerts you by slamming the tool through the part?  Or are you getting different results when you run it?

I have not run it...my comment was more in general of the tool behavior...if it's going through something, it's most likely missing drive information

[JB7280]

Just now, JParis said:

I have not run it...my comment was more in general of the tool behavior...if it's going through something, it's most likely missing drive information

Ah, ok.   Sorry for the misunderstanding.    Everything looks good (aside from wasted air cuts) with detect undercut stock turned off.  Then when I turn it on, it's like it has no idea where the stock is. 

[JB7280]

6 minutes ago, JParis said:

I have not run it...my comment was more in general of the tool behavior...if it's going through something, it's most likely missing drive information

Looks like something was wrong with the stock model.  Maybe it was somehow hollow, or not water tight.  I recreated the stock model based on a solid, rather than the previously created mesh, and everything looks good.  

[Aaron Eberhard]

My guess is because your stock is hollow, so after the first pass it's free to move through it:

 

If you go back to OP18 and right click > Mill Toolpaths > Convert Stock to Mesh, then, edit Op #19 and choose that mesh instead of the one you have chosen, you'll get this result:

 

Edit  > Looks like you figured it out by the time I got 2023 fired up

[JB7280]

7 minutes ago, Aaron Eberhard said:

My guess is because your stock is hollow, so after the first pass it's free to move through it:

 

If you go back to OP18 and right click > Mill Toolpaths > Convert Stock to Mesh, then, edit Op #19 and choose that mesh instead of the one you have chosen, you'll get this result:

 

Edit  > Looks like you figured it out by the time I got 2023 fired up

What could have caused that?  Convert stock to mesh is what I originally did to create it in the first place.  

[Aaron Eberhard]

4 minutes ago, JB7280 said:

What could have caused that?  Convert stock to mesh is what I originally did to create it in the first place.  

The only time I ever run across that is when using Verify > Save STL with too low of a tolerance, but I haven't done that in many, many moons.

[JB7280]

31 minutes ago, Aaron Eberhard said:

The only time I ever run across that is when using Verify > Save STL with too low of a tolerance, but I haven't done that in many, many moons.

I don't think I've ever created an STL/Mesh through verify.  I always convert from a stock model.  But that brings up a question I've wondered. 

 

What do you generally set the initial stock shape, and toolpath tolerance at?  I usually put it at .001.  No idea if that's too high or too low.  

[Aaron Eberhard]

Generally I go for 25% of whatever stock I'm leaving, unless I have a specific reason not to.  For example, if I'm leaving .020", I'll set the initial shape and path tolerance .005ish.   The tool shape will affect the size & processing time the most, but I generally don't go too course with that, especially if you're using ball or bull nose tools, as you can get a lot of cusps and things hanging out that won't really be there.  Again, initial roughing paths, probably .003ish?  

 

Then I tighten up as I get closer to finish paths.

[jpatry]

18 hours ago, JParis said:

opti-rough can't undercut

Man, I wish it could, though.

It would allow me to do some truly heretical things with slot saws.

[JParis]

1 hour ago, jpatry said:

It would allow me to do some truly heretical things with slot saws.

Flowline, Surface Finish contour and a couple of old school tricks and you can do some truly crazy stuff 

[jpatry]

1 minute ago, JParis said:

Flowline, Surface Finish contour and a couple of old school tricks and you can do some truly crazy stuff 

Right, but those are neither stock aware, nor dynamic motion.

[crazy^millman]

5 minutes ago, jpatry said:

Right, but those are neither stock aware, nor dynamic motion.

But you can use them to create the entities needed to do 2D Dynamic as each depth you are using the tool. I have done it this way for years using Dynamic contour.

[Jake L]

Crazy idea... could you program the part with optirough from the Z minus direction instead of from the Z plus direction. Then convert the Z minus toolpath to wire. Then run a 2D contour with no cutter comp from the Z plus direction by chaining the wire?

Sounds kind of bonkers and like a bit of extra work but I think it has the potential to work?

You would have to manually draw the initial entry and exit motions.

[crazy^millman]

4 minutes ago, Jake L said:

Crazy idea... could you program the part with optirough from the Z minus direction instead of from the Z plus direction. Then convert the Z minus toolpath to wire. Then run a 2D contour with no cutter comp from the Z plus direction by chaining the wire?

Sounds kind of bonkers and like a bit of extra work but I think it has the potential to work?

You would have to manually draw the initial entry and exit motions.

How do you think I was dong 5 Axis dynamic toolpaths back in V9 20+ years ago? I would use Pocket and then project to 5 axis surfaces. I would then drive the toolpath using Curve 5 Axis. I could spend days creating geometry, but that is how i could run molds upwards of 170 hours unattended on a 5 axis router without any verification software.

[jpatry]

4 minutes ago, Jake L said:

Crazy idea... could you program the part with optirough from the Z minus direction instead of from the Z plus direction. Then convert the Z minus toolpath to wire. Then run a 2D contour with no cutter comp from the Z plus direction by chaining the wire?

Sounds kind of bonkers and like a bit of extra work but I think it has the potential to work?

You would have to manually draw the initial entry and exit motions.

We've done some things like that

[Aaron Eberhard]

1 hour ago, Jake L said:

Crazy idea... could you program the part with optirough from the Z minus direction instead of from the Z plus direction. Then convert the Z minus toolpath to wire. Then run a 2D contour with no cutter comp from the Z plus direction by chaining the wire?

Sounds kind of bonkers and like a bit of extra work but I think it has the potential to work?

You would have to manually draw the initial entry and exit motions.

It's even easier if you have the multiaxis package.  You can do a lot with Convert to 5 Axis, even if you leave it locked to 3 axis!.   Set up your dynamic/opti toolpath(s) on the bottom plane, then, on the top plane, create a Convert to 5 Axis.  That'll take care of all of your linking and everything as well.

[Jake L]

1 hour ago, crazy^millman said:

I would use Pocket and then project to 5 axis surfaces. I would then drive the toolpath using Curve 5 Axis

 

11 minutes ago, Aaron Eberhard said:

You can do a lot with Convert to 5 Axis, even if you leave it locked to 3 axis!

I'm gonna have to look into convert to 5 axis. I've never played with it but it seems like a really useful tool to have in my tool belt. 

[Aaron Eberhard]

3 minutes ago, Jake L said:

 

I'm gonna have to look into convert to 5 axis. I've never played with it but it seems like a really useful tool to have in my tool belt. 

You're gonna like it. I've done all sorts of crazy things with it.

That and using Unfied > Wireframe > Project (used to be Project Curves in pre-2020).