Machining only the sides of model with complex top geometry

[liamKTZVF]

Hi Everyone

I am trying to machine a mesh model that has slightly sloped sides, and with a complex wavy top (see screencast).

Due to tool limitations I would like to machine the sides first (only) and leave them in finished form.  Then the top will get a roughing followed by a finishing with a different tool.

My problem is that no matter what I try (3D Pocket, Ramp, Contour Scallop etc.) with various options (setting Top Height (since the height varies this is not useful), bound by selections using sketches, slopes etc.) I cannot get to a toolpath solution where the first process that does the sides, does not machine on top.   I can however create toolpaths that only do the top.

How do I get around this, and confine the toolpath to only the sides, especially when the top-edge is not consistent in height?

I have attached the .stl too.

Many thanks

Liam (Yep, a beginner!)

[liamKTZVF]

And here's the screencast...
<iframe width="640" height="620" src="https://screencast.autodesk.com/Embed/Timeline/90757243-2630-41ec-b9be-1239b0313c72" frameborder="0" allowfullscreen webkitallowfullscreen></iframe>

[loudonbendall]

Hi, Why is your model a mesh?

[engineguy · Accepted solution]

@liamKTZVF 

Hmmm, can be done but needs a little imagination, not "workarounds" just finding the right Toolpath. 🙂 🙂

OK, it is a 3D Operation and you want to go round and round a shape so I looked at the 3D Contour, selected the bottom shape and set the "Slope" to angles that I considered were not to be seen on the top shape and put in what I thought would be OK, you will maybe need to "play" with those settings as well as the Bottom height, might need a small Minus to go down a little further! Anyway, I am not going to type it all out, it is after all just a suggestion, much easier to show a couple of images and attach an example file that may point you in the direction you want to go 🙂 🙂 🙂

If it is of any use then up to you to do any "Tweaking" that may be required 🙂 🙂

[engineguy]

@liamKTZVF 

P.S.  I used a big "Bull Nose" and big "Stepdowns" just to get it toolpathed more quickly, old computer doesn`t like to have to crunch a lot of data, to get a decent finish you will need a much smaller "Stepdown" 🙂

[liamKTZVF]

Hi, thanks for the reply!  I bought the original model from Etsy, and it came as mesh only - I didn't want to break any copyright etc. so the example was just a quick model I created to match the basic problem statement.

[liamKTZVF]

Hi engineguy

Thanks for the detailed reply and the effort you went to.  Your approach worked out well and I was able to get the sides done without impacting the top, thank you!

I used a mesh-section and some projections to determine that the slope was about 2 degrees or so.  I then started from scratch, used a 3D contour, and set the slope to between 86 and 90 degrees.  As you can see, beautiful!

Thank you for the advice and pointing me in the right direction, much appreciated!

[liamKTZVF]

lol, I have the same old computer problem! 🙂 Thanks again, your advice was spot on.