Programming a chamfer on a chamfered model...

[antennasys]

If my modelled solid is already chamfered, how do I use 2D Chamfer to cut it??

I tried using 2D chamfer on a square corner, and it works fine.  But for reasons that are not evident, I CANNOT figure out how to use it to cut a chamfer that is in the model. 

Can anyone give me a quick how-to on doing this?

Thanks!

-Spencer

[Steinwerks]

Well normally you can just select the top of the curve, set your Chamfer Width to 0, and set your tip offset to .075 or so (like I have in the screenshot) but since there is no arc, the 2D Contour toolpath specifically avoids the bottom of the edge when using the contour around the square. Seems like a bug to me. What say you @jeff.walters @dave.anderson ? Turning on Pass Extension does not fix this.

Now if you use 2D Contour (Chamfer box checked on the Passes tab) it will round the corners off unless you turn Outer Corner Mode to Keep Sharp Corners or Keep Sharp Corners with Loop:

With Roll Around Corner:

To get the hole to chamfer you will have to play with the Lead settings otherwise it won't clear the opposite side and it'll tell you it cut passes because they would cause a collision.

[antennasys]

Thank you for pointing me in the right direction.

I found the "chamfer" check box in the Countour tool dialog.  If I choose the BOTTOM edge of the chamfer, and check the box, it comes out perfect.  I found reference to the bottom edge in the chamfer checkbox pop-up help.

So, why is there a "2D chamfer" if a contour with "chamfer" checked does the job?  Is it specifically for the case where there is no chamfer in the model??

Slightly confused, but happy for finding the answer....

-Spencer

[Steinwerks]

The 2D Chamfer toolpath is only half-2D. It is model-aware and will avoid collisions with other areas of your model, making deburring much more painless and quick.

Also if I answered your question, please select that as a solution so if others search for this issue they can find it more easily.

[antennasys · Accepted solution]

OK.... my take-away is:

1) Use "2D Chamfer" for sharp corners in the model,

2) Use "2D Contour" with "chamfer" check-box for in-model chamfers.

Would you concur?

[Steinwerks]

It's going to be situation-dependent. If you have modeled chamfers up to a hard edge, then I would use 2D Chamfer. If you have hard corners (and I think this is a bug, or at least not how it's necessarily intended) then 2D Contour will work. If you have a combination, it's going to be a PITA to make 2D Contour avoid part walls, and you might be best served by making separate toolpaths.

There's no silver bullet, basically.

[antennasys]

If that is the case, then I still have no idea how to use 2D Chamfers on in-model chamfers.

Further, in the example you generously gave above, you chose the UPPER edge of the chamfer for 2D contour, and the help specifically calls for the BOTTOM edge to be selected.  As I said, it worked flawlessly when I did that.  And I would never have found it without your pointer.

So, my problem is solved, for now.

Thank You!

[Steinwerks]

The only selection that matters is the one that gets it done correctly, and you'll find that in any CAM software, there's almost always more than one way to do it.

The help files will help, but they certainly aren't the end-all be-all of the software.

[erikj7]

This really helped me, thanks!

[crullier]

Hi folks, so from what I am understanding from the video above is that chamfers are not modeled ?

- In such case, the question I originally came to ask: "how do I model a 45d eg chamfer cut with a 1/8" mill" is no longer valid, is that so?

PS: In current versions, I can't find the chamfer option in the 2d cont. Is it gone for good now?

Thanks

[LibertyMachine]

Yes, you can certainly model the chamfers on. If using an actual chamfer tool, you would select the bottom edge of the chamfer, set the chamfer value to zero, and whatever small value you want for the point to go past the bottom.

If using a non chamfer tool, such as an endmill, you would likely want to use 3D Contour or Parallel

And yes, 2D chamfer is in the 2D toolpaths

[Steinwerks]

---

@LibertyMachine wrote:

And yes, 2D chamfer is in the 2D toolpaths

---

It should be noted that this option only shows in the toolpath with an allowed tool selected such as a chamfer mill, so maybe that's when OP is missing the option.

[crullier]

It is possible that is why I don't see it.

In have question. So let's say I have a 1/4" 120deg mill.

That means that my charger should be modeled as a 1/8" 60deg. How is that
done in fusion. Apparently there is only a distance option?

[crullier]

would someone please care to look at what this is not working?

I modeled the chamfer. I am having two problems. 

#1 I wont find a valid tool path

#2 the one time it did, the tool was cutting into the model

[Steinwerks]

Since you have the top of the chamfer selected as your geometry, you'll want to set your Chamfer Width to zero, and set the tip offset to at least the vertical depth of the chamfer. The handier selection is to use the bottom and set a marginal tip offset so you aren't cutting with the very end of the tool.

Edit: also set your Bottom Height to zero and let the Tip Offset take care of that.

Edit 2 (last one I swear): Definitely use the bottom chain, otherwise the toolpath attempts to avoid the corner material (because it is model-aware, unlike every other 2D toolpath):

Top chain:

Bottom chain:

[crullier]

 The handier selection is to use the bottom and set a marginal tip offset so you aren't cutting with the very end of the tool.

Does not work. 

It also does not work if I only have a chamfer on two sides (not on all 4)

[crullier]

The handier selection is to use the bottom and set a marginal tip offset
so you aren't cutting with the very end of the tool.



Does not work.

It also does not work if I only have a chamfer on two sides (not on all 4)

[Steinwerks]

Set you Chamfer Clearance to zero.

[crullier]

Why does having a chamfer clearance break the solution of the path?

Also, it appears that the operation looks for a closed loop. What if I only want to chamfer one side of a square. It that possible?

[Steinwerks]

Chamfer Clearance is how much you want the tool to avoid collisions with the model, which is why it's usually easier to use 2D Contour with a modeled chamfer instead of 2D Chamfer.

Use an open chain to mill one segment of a contour, here's a screencast showing how to alter your chain (not your part, but this should apply to any model):