topic Re: Recommended stepdown for adaptive clearing? in Fusion Manufacture Forum

Recommended stepdown for adaptive clearing?

Anonymous — Mon, 20 Feb 2017 18:01:33 GMT

My understanding is that the toolpaths created by adaptive clearing trade lighter sidecuts for greater depth of cut. That is, by reducing load on the tool, deeper passes can be made. Theoretically, this allows for faster clearing, but only if my toolpaths actually take advantage of the greater stepdown allowed.

My questions are: 1) am I understanding this correctly and 2) if so, what stepdown values should I be using?

I was previously using the rule of thumb that stepdown should be equal to bit diameter. For adaptive clearing operations, if you check "Multiple depths," Fusion uses a default stepdown value of min(10mm, flute_length). It seems a bit odd to use a constant stepdown value regardless of bit diameter. Any guidance is appreciated.

Re: Recommended stepdown for adaptive clearing?

LibertyMachine — Mon, 20 Feb 2017 18:08:10 GMT

A good portion of guidance is going to depend greatly on what you have for equipment and tooling. Are you dealing with an anemic desktop mill that struggles with anything larger than a 6mm endmill, or are you driving a Haas UMC-750?

Speaking from personal experience, I often run adaptive tooling approximately 80-90% of the flute length, assuming the part requires it. (Obviously, if I'm working with a short part, there is only so much I can do)

If the depth of the part is greater than the flute length, I'll break it off into a couple operations, splitting the depths evenly

For Fine Stepdown, I determine how much of a "steps" pattern I can live with and how the tool will try to fit into features

Lastly, what materials are you working with and what's your tooling selection?

Re: Recommended stepdown for adaptive clearing?

Anonymous — Mon, 20 Feb 2017 18:27:28 GMT

I'm using a ShopBot. I'm not entirely sure what the how much power is being supplied to the spindle, although I believe the recommended range of operating speeds is 8,000 to 16,000 rpm. Presently I'm cutting wood and MDF, with either a flat 1/4" bit, flat 1/8" bit, or ball nose 1/4" bit (I also have a 3/4" ball nose coming soon).

If you are using depths of 80 - 90% of flute length, that is obviously quite a bit deeper than my bit diameter rule of thumb. It sounds like I can be more aggressive than I have been.

Re: Recommended stepdown for adaptive clearing?

LibertyMachine — Mon, 20 Feb 2017 18:33:14 GMT

Yes....and no. I am running a 25HP DMG Mori Duravertical 5100. It has no issue with those parameters. I can't say the same for a Shopbot, as I've never run one.

Good general rule of thumb would be to maximize your axial engagement with light radial cuts. There is going to be some experimentation involved, as there are many unknowns. And you will either stall the machine or break the bit in learning where those lines are. Lesson learned, now back it off 10-15%

Re: Recommended stepdown for adaptive clearing?

Anonymous — Mon, 20 Feb 2017 18:46:39 GMT

OK, thank you. And just to loop back to the original question -- I take it I am correct in thinking that adaptive clearing is designed to generate toolpaths that put a lighter load on the tool, which should allow for deeper cuts? I understand there is no hard and fast rule regarding exactly what parameters will work on my equipment, but that at least is the idea behind adaptive clearing vs. 2D pockets?

Re: Recommended stepdown for adaptive clearing?

LibertyMachine — Mon, 20 Feb 2017 18:49:56 GMT

Absolutely correct. Deep axial cut, light radial. Fast. Very Fast.