Help Finishing Multiple Interconnected Slopes

[mkraushaar]

Hello all! I'm new to the forums and new to Fusion. I'm just at the beginning of this learning curve and recently took on my first large-ish cnc project: An architectural landscape out of MDF.

We're using a Carbide3D Shapeoko to cut out ~15 pieces that need to come together, I'm using the shapeoko to add holes for floating tenons to aid in alignment and assembly. They provided a file and I used a series of bodies the size of our stock to slice the main body and produce a series of machineable blocks.

The problem I'm having is that a small lip of material remains at the top and bottom of some of the slopes during machining.

Obviously this shows up in the real piece and disrupts the alignment of the slopes. I had fixed it on a previous piece by telling the parallel finishing path to 'Machine Steep Slopes' though that seemed like a kludge and added a lot of machining time. I also felt as though I was having mixed success having the parallel path use a range from 1-89 degrees of slope to avoid machining the tops and sides of the piece.

This is my previous success. I've been copying the four operations from cut to cut and then adjusting them so they are focused on the right body and the only change that I think I've made is that I adjusted the stock to more accurately reflect our real-world stock and change how the piece centers up and down in the stock, but I thought I had accounted for that with offsets on the workheights.

I'd love any help with this slope issue, but also would be deeply appreciative of critique or comment on my approach and execution of some of this work. I'm very new to fusion and am also hampered by having an aging computer that makes it hard to experiment and find proper solutions. New one is on the way though!

Also was wondering if there were any forum post collections of tags / labels.

[Zack.tenaglia · Accepted solution]

Hi @mkraushaar!

The differences you are seeing part to part has to do with the way your stock is setup. In the first setup, the stock is just barely larger than your model, so your parallel is cutting all of the stock up to the top of the model.

In the other 3 setups, the top of the stock is a fair bit higher than the top of the model, so the parallel toolpath isn't hitting the stock at the very top (it stops at the top of the model). The same seems to be happening at the bottom of the model, where the stock extends past the bottom of the model. This is by design: the parallel toolpath is only going to machine the model surfaces that it sees, and won't extend past those surfaces. There is no tangential extension option for that toolpath. 

Hopefully those pictures show what I'm talking about.

There are a few different ways to fix this. Here's a couple ideas that seem to work:

1. Line up the bottom of your model with the bottom of your stock, and then face off the extra stock on the top of the model using the "Face" toolpath.

2. Change the location of the model within the stock so that the top of the model aligns with the top of the stock. This will retain the lip at the bottom of the toolpath.

3. Use stock that has the same thickness as your model.

If you wanted to keep the stock setups as they are, you could also try to extend the surfaces of the model past the top of the stock. That would allow you to have a smooth transition at the top of the model, but it won't technically be accurate to the model. I think it would also be a bit difficult to extend the surfaces of the current model since there are so many individual faces. 

I hope this is helpful, let me know if you have other questions!

Best,

Zack Tenaglia