Parallel Finishing Tool Path Cutting Above Stock height

[jason.chinchen]

Hello all. I am not new to CAD/CAM but I am to Fusion. I am used to working in Autocad/VisualCad for machining wood. 
I teach a ski and snowboard manufacturing class at Sisters High in Oregon. We have been using VisualCad to parallel finish the wood cores. VisualCad will set the tool paths to a height limit of the top of the stock, but it seems that Fusion wants to run the tool along the path of the top of the finished core and not limit the z to the top of the stock. This is resulting in the first pass being fully in the air....

I imagine it is a stock setting or a multiple pass setting but I havnt been able to change this behavior...maybe I am using the wrong kind of machining function and Fusion thinks differently than VisualCad? 
Any help in getting the multiple passes to be limited in height to the top of the stock would be awesome.

Some details:

My stock is the same thickness as the final core should be in the center. (10.5mm)

I am using a 1 inch flat router bit in a custom machine. (16x80 Snowboard materials.com CNC)

The spindle is centrifugal and will bog down if I cut too deep or too fast so I can only cut about 1/3 stepovers at around .2 deep at a spindle speed of 25000 and a feed speed of 40.

[seth.madore]

For a better chance at assistance, could you share your Fusion file?
File > Export > Save to local folder, return to thread and attach the .f3d file in your reply 🙂

[jason.chinchen]

Doing it now!

Jason

[jason.chinchen]

Here is the working file...

[seth.madore]

That's the .stl file, I would like to see the Fusion .f3d file that would show me your toolpaths.

[seth.madore]

Or .f3z file, as the case may be

[jason.chinchen]

Oops sorry....

[seth.madore]

So, yeah..

Parallel and many of the other 3D toolpaths don't recognize excess stock and aren't intended to be used as a roughing toolpath. To remove the excess stock, one should use a 3D Adaptive or Pocket toolpath.

However, if you have access to the Machining Extension, one could rather easily use the Trim Toolpath function to clean up the excess

[jason.chinchen]

I think I understand you.

The thing is that there is no excess stock. The stock is already to the finished thickness (the top of the finished part).

I cant just enter the actual thickness of the actual stock and the tool paths should not need to go any higher? I think I have access to the other extensions with my educational license.

[seth.madore]

The Multiple Depths passes option does not adhere to the Top Height settings, it is permitted to violate that.

[jason.chinchen]

Heres the working file with an adaptive clearing setup....

So should I use that first and then apply a single parallel finishing pass?

Thanks again

[jason.chinchen]

"The Multiple Depths passes option does not adhere to the Top Height settings, it is permitted to violate that."
OK...is there a way to constrain it? Or should I use a different machining function and then use a parallel pass to clean it up? Visualcad was easier in the sense that it knew where the top of the stock was and didn't waste my time or machine milling the air....plus I only needed one setup.

[seth.madore]

Your Adaptive and Parallel should work just fine.

Multiple Passes cannot be constrained as easily as a single pass in most of the 3D toolpaths (Parallel, Contour). HOWEVER! One could create multiple Parallel toolpaths and turn on "Stock to Leave" (while leaving "Multiple Depths" turned off), set your Axial Stock to Leave to a value equal to your preferred stepdown, turn on Rest Machining (From Setup Stock) and get this for a toolpath: