Dynamic Boundary Violation

[Frank Caudillo]

Came across this little surprise in 2020 just now. Dynamic path is violating the boundary when it leads off the material. The outer most path is a finish contour at 0 stock (Verify green) and the dynamic path violating it is leaving .01" stock on the wall (Verify purple). I can easily fix this by adding more stock to leave, but I feel like dynamic shouldn't do this regardless. Has this been a thing for awhile that I'm just now encountering?

[Chally72]

What is your toolpath tolerance set to? Can you post the file?

[Frank Caudillo]

1 hour ago, Chally72 said:

What is your toolpath tolerance set to? Can you post the file?

Total tolerance is .001". See the file for what's going on. When I created this example using the exact same geometry and toolpath settings I noticed that the problem goes away when only one "area" to rough/finish is chained. With all three sections chained you'll see the boundary violation behavior happen.

DYNAMIC_BOUNDARY_VIOLATION.mcam

[Chally72]

What is happening here is that there's a sliver of air region from the extension off of the middle jaw island that exists beyond the lefthand machining region:

 

Air region extents are automatically sized based on the diameter of the tool selected, and that sliver is being created as part of the air region extents of this chain, perpendicular to the chain edges:

 

 

Since the toolpath has no knowledge of any geometry except what we're feeding it for chains, it sees that sliver as a valid air region. A solution is to simply add the top left jaw face as an avoidance region to eliminate the air sliver, which gives you this:

 

The ability to add multiple air regions also adds quite a bit of complexity in how overlapping regions are dealt with, so avoidance regions start to become more necessary to control motion around and between the desired areas. Hope this helps!

[David Colin]

As air region extention value is arbitrary, software couldn't be smartier to stop any air region extention if it encounters another machining region?

[Chally72]

Some reference info- Air region extent is 4x tool diameter. I imagine overlapping region trimming is tough because we have knowledge of only the input chains, and then each region would have to be cross checked against every other region and some intelligence applied to the result. I'm sure this will see many improvements in the future- the ability to add multiple air regions was just introduced, and the functionality will continue to evolve release to release. For now, giving the path a little more knowledge of surrounding geometry is enough to get a good path.

[Frank Caudillo]

Thanks Chally. That makes a lot more sense now. I had never seen this behavior before now so I was pretty puzzled. I'll keep in mind for the future that dynamic might just need more info if I have any issues.