Unexpected behavior using Stock Contour in 2d Contour

[Garrett_Wade]

On occasion i'll use 2d contour and add multiple passes then use the Stock Contour check box and select the profile of the part to cut out the excess passes. Today on a fairly simple part I noticed when using this workflow the tool path is seemingly randomly extended and collides into my part.

As a test I tried to project the geometry into a sketch to drive it off that rather than the part itself yet I get the same results.

I'm thinking this is some sorta unintentional bug? I've included photos below

[engineguy]

@Garrett_Wade 

That would most likely be because you didn`t actually select a Stock Contour to limit the toolpath so it just defaults to include the whole part, see image below and attached file.

[Garrett_Wade]

@engineguy 

After a number of tests I replicated the issue for this post, thats not my working file so there is some small differences.

It appears you selected JUST the face to be machined as stock contour in your upload as shown below:


And while this does seem to work, its not the workflow i've used for the last few years and I still think i'm getting new behavior. Please view the images below which show only 1 chain selected and using the entire part as stock contour and then how paths are added that drive the tool through the part.

I've not seen 2d contour generate tool paths in areas not selected.

I am for sure curious if you or anyone else thinks this is normal behavior and i've somehow just not experienced this over the last 4+ years.

[engineguy]

@Garrett_Wade 

The error is because you have selected a 3D contour and tried using a 2D toolpath, Fusion has tried to follow your selection and failed miserably using the 2D Contour, hence the bad toolpath 🙂

If you only select the edges that are on the same plane then it will work correctly, ie don`t select the 3D edge of the Chamfer. See image below and attached file.

A tip, please just use the Medium option for uploading images, the Large takes up a lot of space and download data 🙂 🙂

[Garrett_Wade]

@engineguy 

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@engineguy wrote:

@Garrett_Wade 

The error is because you have selected a 3D contour and tried using a 2D toolpath, Fusion has tried to follow your selection and failed miserably using the 2D Contour, hence the bad toolpath 🙂

If you only select the edges that are on the same plane then it will work correctly, ie don`t select the 3D edge of the Chamfer. See image below and attached file.

A tip, please just use the Medium option for uploading images, the Large takes up a lot of space and download data 🙂 🙂

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Noted and thank you on the image quality.

As far as the explanation on being 3d sketch driving it...i'm still confused or not convinced.

In this example I did select a  3d sketch but on the heights tab i'm telling it to drive at a specific height which in the past as worked without issues for me.

But if what you say IS the cause... it would lead me to believe that I could create a sketch and project the 3d geometry thus effectively flattening it to a single plane -and then drive it off that.... but that still results in the same issues with the generated toolpath. 

[Garrett_Wade]

I've created another example which has all the same type of geometry plus more as the original but this one seems to behave as expected

When I select 3d chain using 2d contour and then multiple passes and limit those to the stock contour it does not give me issues. This is why i'm not quick to accept your explanation.

(PS the areas in green were only added to make it so you could not simply select the chain on the top of the part to drive the tool rather than the 3d geometry)

I look forward to either finding out the true root cause of this issue and why it only seems to happen sometimes for me or highlighting it as a bug so it can be fixed.

[engineguy]

@Garrett_Wade 

I didn`t mention any Sketch, the Contour is selected from the Model.

A 2D Contour is not going to move in 3 Dimensions, it can`t do that and the Model that you uploaded can only be machined on a Multi axis CNC Machine using a Multi axis toolpath, otherwise it is impossible to machine that Chamfer into the corner as on the Model.

If you want a toolpath that will follow a Line/Solid edge in all 3 axis then try using the Trace toolpath, it will follow around in the X/Y Plane and then follow the selected edge down in 3 axis at the same time, it wil however create a radius of the tool cut into the part whic is not desirable IMHO 🙂 🙂

[Garrett_Wade]

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@engineguy wrote:

@Garrett_Wade 

I didn`t mention any Sketch, the Contour is selected from the Model.

A 2D Contour is not going to move in 3 Dimensions, it can`t do that and the Model that you uploaded can only be machined on a Multi axis CNC Machine using a Multi axis toolpath, otherwise it is impossible to machine that Chamfer into the corner as on the Model.

If you want a toolpath that will follow a Line/Solid edge in all 3 axis then try using the Trace toolpath, it will follow around in the X/Y Plane and then follow the selected edge down in 3 axis at the same time, it wil however create a radius of the tool cut into the part whic is not desirable IMHO 🙂 🙂

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I think there might be some miscommunication.

My intention is NOT for the contour to move in 3axis but only to use geometry on the model to drive it in in 2axis (XY), in this case the selection driving it happens to be in 3axis. Which in the 2nd example I've shown works without issues and does not add additional toolpaths.

I'm not concerned with anything related to machining the chamfer. We have a number of ways to handle that. 

If you look at the 2nd model I just uploaded you'll see a model with similar geometry, selecting 3d geometry on the model but driving it with the heights tab at a specific height. The 2nd example model I uploaded also has a chamfer that wraps around a corner and it provides a toolpath that is inline with what i'm used to seeing and what i'm looking for.

On the original model EXTRA paths are added with this same workflow. Those extra paths are not even tangental to the final section of the the toollpath so i'm not sure how fusion is generating those or why they are showing up.

[Garrett_Wade]

In this example i'm selecting the 3d path you mentioned to drive the tool path from the original post around the part and clean up this vertical section of stock highlighted below.



I have no issues with this, this works great.


My issue is when using stock contours on the entire part as shown above its driving the tool through the part into areas not selected:

[engineguy]

@Garrett_Wade 

Looked at your example file but as you have chosen to Protect/Hide stuff then I am not able to check anything but it appears that the shape was selected from a sketch so that the selection is in the X/Y plane then if that is the case it will work as expected because all sections are in effect 2D.

I think that you will need an Autodesk support person for this, if you go to the bottom right corner of your screen you can contact support via that route.

[Garrett_Wade]

@engineguy 

I'm not aware of any protection or hiding that you speak of. 

I've included photos below that hopefully help illustrate the issue better on this part. 

Selection made to drive 2D contour and stock contour selection shown, notice the small area in blue selected:


Resulting tool path, please notice how the tool path added many new sections that wrap around and run into the part. These "extra" paths only exist when using "Stock Contours" and selecting the bottom of the part as the coutour.


If I remove stock contours entirely I get a good and usable tool path but its a bit longer than needed:


So what I am attempting to do is select "stock contours" and use the outline of the part to trim the parts of the tool path that are just air cutting to give me a tool path like this:



Notice out especially the outer most pass is heavily trimmed in the areas where it would NOT be over the part and just air cutting.

The root of my issue is that for some reason on THIS part unlike any part where i've used this technique in the past it seems that trying to use "stock contour" and selecting the outline of the part to trim the 2d tool path is not only trimming the toolpath but also ADDING a number of lines of code and cutting into areas of the model that were not selected.

[engineguy]

@Garrett_Wade 

Ah, OK, so this is not locked off and hidden ??

As previously posted, I have no idea what you are trying to achieve and it may well be a "bug" but I am not an Autodesk employee so do not have access to the "stuff" behind the scenes that the Developers work with which is why I suggested that you contact Support via the little Autodesk icon in the lower right corner of your screen.

Apologies but that is all I have on this for now 🙂

[seth.madore]

I understand what @Garrett_Wade is trying to achieve and what's going wrong. 2D Contour with Stock Contours turned on should not be going through the side of the part like that.

This is being cause by this fillet:

 If we shorten up our selection just a tad:

 

Results are:

 

Forgive me if I've repeated something already stated, I did not read each post 100%, only enough to get the gist of what's going on

[engineguy]

@seth.madore 

Hi Seth, yes, that is exactly what I did to make it work, I think this is possibly related to the old "fillet at the edges of open pocket" but the last section is a 3D line so it is a problem, and yes, I also agree that using the "Stock Contour" shouldn`t be affecting the toolpath but that is only something that the Developers can answer 🙂 🙂

In the Posters second model it does appear to be selected from a sketch (X/Y Plane) so the 3D Chamfer line is flattened out, maybe ???? 🙂 🙂

[Garrett_Wade]

@seth.madore 100% agree its that last small bit of the chain in combo with stock contour that is causing the issues.

I've tried to recreate this "issue" in another part with nearly identical features (uploaded above in this thread) and it does not exhibit the same weird behavior.

I mentioned above the reason I was selecting that last chain (the section on the camfer) is because I believe it is necessary to not leave stock on that wall as shown below if I remove that chain:


My current issue is not how do I finish this part as there is many work arounds I can do like using different selections for stock contours, using a different body or manufacture model with no chamfer...etc.

But I wanted to make sure i'm not crazy here, and that is an acceptable way to use "stock contours" (to effectively trim a path)....and if this was an issue/bug that it was documented ASAP so it can be looked into.

[DarthBane55]

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@engineguy wrote:

@Garrett_Wade 

A tip, please just use the Medium option for uploading images, the Large takes up a lot of space and download data 🙂 🙂

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Are you sure that large pictures take up more space and data than bold characters?  🤣

As a side comment, we always are able to pick 3d geometry for 2d contour, Fusion flattens it out.  The inconvenient is that it will break those 3d sections in small line moves.  To avoid, use the slice tool in a sketch.  But still, 3d geometry in 2d contour were never a problem.

[seth.madore]

I've opened up CAM-35904 to investigate this.

[Garrett_Wade]

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@engineguy wrote:

Ah, OK, so this is not locked off and hidden ??

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I actually did not draw this model but I believe the lock you are seeing is just the indicator that Sketch1 is "fully defined"

[Garrett_Wade]

@seth.madore 

Thank you!

[engineguy]

@DarthBane55 

Might be fine for you but I don`t have a super fast connection so I have to sit and wait for Large images to load 🙂

Are you sure that large pictures take up more space and data than bold characters?  Really??? Ah well, each to their own 🙂