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2D Chamfer and cutter comp

DarthBane55
Advisor

2D Chamfer and cutter comp

DarthBane55
Advisor
Advisor

Hi, it looks like cutter compensation (G41/G42) is not enabled for 2D Chamfer operation.  Even when using "wear compensation", it does not output cutter comp.

Is there a way I can enable this in the post?

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Accepted solutions (1)
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DarthBane55
Advisor
Advisor

Let's try this again! (bump)

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DarthBane55
Advisor
Advisor

@serge.quiblier 

What do you think, possible to enable cutter comp on 2d chamfer?

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DarthBane55
Advisor
Advisor

Hi, I originally posted this question Dec.19 2022.  Could someone from Autodesk at least say "it is not possible to do this", or that yes it's possible, at least so I know if I should forget about it or not, please?

 

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seth.madore
Community Manager
Community Manager

@DarthBane55  Sorry for missing this post, I don't frequent this forum too often.

Unfortunately, the cutter comp option in 2D Chamfer is completely unhooked from anything that actually passes the needed info to the post processor. There are some existing tickets that are opened, but it never seems to rise to a high enough priority to address. :disappointed_face:

(btw; I think the tickets are simply to remove the "option" of comp)


Seth Madore
Customer Advocacy Manager - Manufacturing
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DarthBane55
Advisor
Advisor

Hi @seth.madore 

Thanks for the answer.  I just noticed that the "compensation type" settings are in fact different than the rest of 2d operations, so ok, I accept your answer.  So basically, you are saying that it is not passing the "compensation type" information to the post at all right?

I have done some "cheating" in the past, by enabling some funky stuff from the post by using a setting in an operation for a completely different purpose, to make the post do things it shouldn't.  In this case, because it is 2d, I don't use "smoothing".  So I'm thinking that for 2d chamfering, if "smoothing" is checked, it could provoke G41/G42 (I would take it upon myself to ensure the lead-in/out is correct for this).

I think I can make that work, now that I know the "compensation type" is not being passed to the post.  But can you just confirm that this is the case please?

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seth.madore
Community Manager
Community Manager
Accepted solution

There are numerous tickets on this issue (2D Chamfer and "compensation" of any type) and they all refer back to the same underlying issue; the hsm-kernel is hardcoded for one comp type; computer compensation


Seth Madore
Customer Advocacy Manager - Manufacturing
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DarthBane55
Advisor
Advisor

Thanks a lot!

I will cheat it by disabling smoothing for 2d chamfer operation and forcing cutter comp when smoothing check box is checked!

Thanks for confirming the behavior of 2d chamfer!

seth.madore
Community Manager
Community Manager

@DarthBane55 wrote:

I will cheat it by disabling smoothing for 2d chamfer operation and forcing cutter comp when smoothing check box is checked!

 


Very clever...


Seth Madore
Customer Advocacy Manager - Manufacturing
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serge.quiblier
Autodesk
Autodesk

Hello @DarthBane55 , @seth.madore 

 

I was busy training people the previous week.

Hence my silence.

As you have figured, Fusion does not output the onCompensation event into the ncStream.

So, the post can't react.

I think it was a quick way to avoid the usual issue with 2d comp for chamfer.

Which diameter should we consider for driving the toolpath?

 

sergequiblier_0-1675183833041.png

 

Anybody will have a different opinion.

 

One and two make sense as they are tool related.

And can be determined without incertainty.

 

(And I have not added the middle of the chamfer, or the intermediate diameter on the tool, between top and bottom)



Serge.Q
Technical Consultant
cam.autodesk.com
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seth.madore
Community Manager
Community Manager

@serge.quiblier in my opinion, if one were to use cutter compensation with chamfer tools, I would want to see it driven off of #1, as it's the most easily measured diameter


Seth Madore
Customer Advocacy Manager - Manufacturing
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serge.quiblier
Autodesk
Autodesk

It's in fact the one that will always exists, as we can chamfer using a drill or a tool without the bottom flat.



Serge.Q
Technical Consultant
cam.autodesk.com
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DarthBane55
Advisor
Advisor

I would leave it at the tip of the tool, just like when doing 2d chamfer with 2d contour toolpath, why would it have to be any different?  2d chamfer in 2d contour does output G41 correctly.  I see this as exactly the same thing, am I missing something?

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DarthBane55
Advisor
Advisor

@serge.quiblier 

I think I know why cutter comp is disabled. 

Well 1st off, I am giving up on cheating this, it will not work.  I cheated it to output G41, but then, it switches G41-G40-G41-G40 one after the other, because there is no state of cutter comp passed, and understanding the section where this is handled in the post, I can see that this value being not there, it will not be possible to make it work correctly.

pendingRadiusCompensation is a critical variable that tells the post if the cutter comp state has changed or not, and it does this on each X-Y-Z move, so it knows when to G41 and when to do G40.  At least, that's how I read the code in the post.

 

So, why is cutter comp not enabled?  I believe, it is for safety reason.  Autodesk covering themselves for scrapped parts here, for beginners.  Because this operation can avoid walls with a given amount, if you gave us cutter comp, and we made the chamfer bigger on the machine by adjusting the diameter offset, there is the potential that the tool would hit that wall that it shows as being avoided within Fusion.  The tool getting closer to the part, the outer edge of the tool would at one point start digging "sideways" into the wall to avoid.

 

I think this is why you didn't enable this, and I understand it now.  It is kind of the same situation as when you do multiple contours in an operation that are not on the same plane, Fusion sends the tool to the clearance plane between profiles, to cover itself for beginners.  Something I asked before, if we could have a "power user" check box and unlock all these restrictions which we are used to deal with, as you get experience and know what to look for, it would be great.  But I understand that this would complicate things a lot on your end.  I accept the limitations.

 

I think this explains it, I am writing it for my own future reference if I forget the reason and start trying to provoke the cutter comp on 2d chamfer again lol, but it might benefit someone else trying to do the same.  I think I got it right, if not, please correct me!