4th axis lathing with live tool

[Anonymous]

Dear Community,

I am very new to CAD and CAM. My father recently bought a CNC router, the High-Z S-1000T with a Roundino 120 4th axis. He knows nothing of computers and CAD so it's up to me to make it all work.

I've made round part with a hole through it along the rotary axis.

I believe the optimal solution for making this part, would be to turn it on a lathe, but I don't have that. 

My question to you is:
How can I approach this project with the tools I have. 

I'm thinking either turning it with a live tool which I haven't found a way to set up in Fusion 360. 

Alternatively turn it to a vertical position and use a slot or lollipop tool to mill around it. In this case I just can't make Fusion create a toolpath that reaches into the groove. 

How would you approach this with the limitations I have? 

I hope to hear from you soon! 

Sincerely
Peter

[xander.luciano]

Hello there!

Welcome to CNC'ing! You've set yourself up with quite the challenge there as there is no real easy way to do this per se. I could think of a few hacks to trick it into working, but nothing I would honestly recommend doing. 

Do you need to cut this part, or could you start with a square part first and then work your way up? This is really a part that should be cut on a lathe. 

Sorry bout that,

-Xander Luciano

[Anonymous]

Thank you very much for your reply. 

As it is right now I have no option to lathe it. Since I posted the thread I have managed to come a little closer to using a slotting tool to mill the outside. I also found some posts on dividing it into multiple chains to trick fusion to wrap the path around and that way mill it in a lathe kind of fashion.

I think the best right now is probably to put this project on the shelf, and see what I can do about using a lathe in the future.

Thank you for your input. 🙂

[Anonymous]

Also agree that's really something that should be supported - a mill cutting a profile on the side of the stock that's rotated in steps seems pretty basic and should give decent results.

[daniel_lyall]

You can do that but it's a non standard way, you just turn you A into a spindle then run a profile cut, you more than likely would not get Fusion support if you did it, sinces fusion does not natively support it.

[Anonymous]

Right, guess one can find a way to control the A axis manually from the machine control side while also running the program.

I would think repeating the profile cut many times at small A increments would give better results than just turning A like a lathe spindle though.

Could probably write a small program that takes the Gcode coming out of any 2D CAM and repeats it with A movements inbetween the right number of times for a given resolution...

[Steinwerks]

This wouldn't be ideal but a single-pass Parallel toolpath along the X axis and then patterned around the rotary would do the trick. Not what the op was asking for though, and won't be as nice.

[Anonymous]

You guys come up with some neat creative ideas. That's really cool!

I think a rotary parallell operation sounds pretty plausible. That's one approach I haven't thought of yet and I too think it'd be a really cool feature to support a lathe operation with a live tool. Might not seem as professional but it'd be a great help for hobbyists with limited tools. I wonder though if an operation like this would be precise enough? I don't see why not.

Thank you all for your input! 🙂

[Steinwerks · Accepted solution]

Alright I've attached a file with a couple options laid out:

1) Project with a 180-instance circular pattern. You could actually do this with a straight line instead of the profile but this was a quick way to get there and I had already made the Projection Sketch:

2) Parallel with a 3-instance circular pattern:

File attached. Hope this helps!

[Anonymous]

Wow. this is quite amazing! Thank you so much for spending time on making these tool paths!! It looks great!!

I'll try to move forward with these operations. I will post photos or video of the process and results when I get there. 🙂 This is also a great way for me to learn as I can see how you've set it up. Extremely useful!!

Again thank you very much! 😄

[Anonymous]

Nice indeed!

But note that this toolpath wouldn't be appropriate for machining as is as it's all a single Z pass. Eating into 5mm of material at a time won't end up well.

What we really need is a 2D path with a Z offset to use the side of the cutter, and repeat that at multiple A angles...

[Steinwerks]

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@Anonymous wrote:

Nice indeed!

But note that this toolpath wouldn't be appropriate for machining as is as it's all a single Z pass. Eating into 5mm of material at a time won't end up well.

What we really need is a 2D path with a Z offset to use the side of the cutter, and repeat that at multiple A angles...

---

My example is pretty much just that. If the part is wood, it's likely to not even matter. Axial stepdowns can be utilized, all sorts of techniques really, so really I just put out there that this part is indeed possible using a 4th axis with decent results.

Personally I'd use a 3D Adaptive and pattern it around four times in the same manner, then work on the finishing. If one wants to use the Project technique you can keep the nose of the ball mill off the material by offsetting the line to the side, and the pattern will work the same.

[daniel_lyall]

@Anonymous you just move the line out by X amount so it can be ruffed, it's only the first cut where it can be a problem, the next cut will only be a mm or less.

[Anonymous]

I'll of course create the necessary offset toolpaths to rough out the shape indeed. These examples are great for me to see how it can be done. These are techniques I didn't think of at all in the first place! I've managed to clear out the inside material so I can work on the outside now. 🙂

I also managed to almost finish toolpaths to mill the outside with a slotting tool using a ramp with the model sitting vertical. Only get one error on the last pass which I'm trying to figure out. After I looked at your toolpaths I figured I'd need additional stock to use to hold it in the chuck, or use a screw that I fit through the center hole. I could probably do that and still get decent enough precision. 

This is exciting 😄