3D Contour issue

[jdsp229]

I use the 3D Contour toolpath very regularly, but am having a strange issue with this part. In this part there is essentially a slot with angled walls that runs the length of the part. On one end, the walls open outward at an angle. For some reason, I cannot get the toolpath to extend to completely cut where this happens. I first thought it was an issue with my containment parameter, but I have tried every combination of contact point boundary, containment boundary, machine shallow areas, separate toolpaths, etc for these surfaces. Touch surfaces is turned on, and all the surfaces I want machined are selected. A sperate toolpath with only the trouble surfaces selected will not generate at all.

The only toolpath I can even get to even generate is with Silhouette boundary, tool center on boundary(no offset), and contact point boundary off. I've attached a couple pictures so you can see what's going on. Tool is a 1/2" indexable ball endmill.

[seth.madore]

Could you share the file here?
File > Export > Save to local folder, return to thread and attach the .f3d file in your reply

[jdsp229]

I should have done that in the first place. The file is attached here. Thanks for looking at it!

[seth.madore]

Well, there is something definitely screwy going on here. I suspect the toolpath is failing because of extremely small gaps in the surfaces (we're talking less than .00001"). I was able to determine that when I made a patch offset of those surfaces:

 Zoomed WAY in:

Now, with these patch surfaces, we can now use "Touch/Avoid" and accomplish this:

 

If you have access to the Toolpath Trim option from the Machining Extension, we can clean those extra passes up quite nicely.

I've attached the file with what I've applied to it. I think this does qualify as a bug, I will try to get a report written up this week

 

 

[jdsp229]

Seth,

That definitely seems to be the issue. I tried the patch offset on the other side, as well as several other models that are in the same family as the issue model and it has worked perfectly. I had not thought to zoom in to those areas and look for an problem like that. Really appreciate the help.

I know the model that I sent is a bit of a mess in the timeline, but the drawing the part is based on was not very well done and I was attempting to figure out the best way to model it. Would you recommend a different way of going about modeling the angled surfaces to help avoid this issue?

[seth.madore · Accepted solution]

Actually, yes. I deleted the 2X R.250 on the top of the part (they were from the Combine operation) and remodeled them. Result on your file, with no patch surfaces:

 

Now, this can likely be cleaned up some WITH the use of Patch surfaces. But, in regards to the modeling issue, I suspect the failure was caused by the order in which you applied the corner radius, with one of them being driven by the Sketch > Extrude and the other blended in with the Fillet command. Applying them both at the same time with the Fillet command allowed a chance for those intersection points to "heal".

[jdsp229]

That makes perfect sense Seth. Thanks again for the help. The patch surface fix worked on the rest of the models and I am about to finish up the job. I will keep this in mind the next time I have a similar situation with fillets.