Why are these leads so expansive?

[JetForMe]

This is a 3D adaptive toolpath. The block is my stock and the cylinder is part of the model protruding past it. I set some entry points on other sides of the stock, but notice how far it generates some of these leads. The danger is that it'll collide with the tailstock that's right there.

I extended the cylinder well past the stock because the previous design was that way and it seemed to do better. But now I've got these massive leads and I can't keep it from hitting the fixture. I've broken my only two endmills tonight doing this. There's enough room around the stock for the tool to stay close-in to it, with maybe 2 mm of clearance. How can I keep the tool closer to the stock? 

[johnswetz1982]

Use a sketch to constraint the operation to just the block portion. Though if you use no offset then the mill willwant to helix in for an entry.

[engineguy]

@JetForMe 

As the Leadin/out does not actually leadin to the Stock at any Leadin feedrate they are IMHO pretty much useless, changing the distance doesn`t seem to do anything, BROKEN ??, they only take the cutter close to the Stock but the cutter entry is at Cutting feedrate, if you try setting the Leadin/out to "0" then the distance you will get will be a fraction more that the cutter diameter, maybe that will work for you, it is the only way that I know of to start cutting outside the stock, otherwise as John @johnswetz1982 rightly points out you will get a Helix entry, that may be the best option for what you are doing anyway 🙂

Rough example file attached, for illustration only !!

Stay Safe

Regards

Rob

[Anonymous]

Hi @JetForMe , see attached file. If you add a solid body to represent your fixtue but in the job set up select it as a model body the tool will not go through it. I would recomend making the fixture model extra big to keep more clearance.

Jason

[SendItCNC]

^^^^ This.

Model the fixture, then select it as Fixture in setup -- that will give you collision detection in CAM simulation. Then you can also add it to the Model in setup, so the tool path navigates around it. OR you add it just to the Model option in the Geometry tab of the 3-d Adaptive operation. That way it won't be part of the setup model for other operations. In any case, once you add the fixture to the model, you may need to adjust the Heights tab since the values for Model Top and Model Bottom may be affected since they will include the fixture.

[JetForMe]

Yeah, I finally took the time to model the fixture, and also along the way figured out that I can model geometry to keep the tool out of the fixture. Adding it to the model might be the best way to go. Would be nice if you could just tell a toolpath to "avoid fixture" or something like that.

I also wish it had a way of letting you specify an arbitrary margin on the fixture geometry, since I modeled it as precisely as I could, and the toolpath still gets closer than I'd like.

[SendItCNC]

If you add the fixture to the Model option in the tool path (not necessarily in the Setup) that effectively tells that tool path to avoid the fixture.

If you use "Shaft & Holder" you can specify the clearance relative to geometry to be avoided.

Enjoy.