Using Fusion 360, I easily can select pockets of my model and cut them with a variety of different tools in sequence. What I can’t seem to figure out is whether I can cut the majority of a pocket with, say, a 1/8th end mill, then refine it with a 1/16th without air cutting 99% of the area during that second pass. Is there no progressive means of combining tool operations where it intelligently knows what has been cleared in the previous operation and refines it?
Thanks!
Cute. I’ve actually watched that once before a while back, but had forgotten it covered that aspect of the process. Thanks for the reminder! 
Actually, after watching it again, I’m not sure I’m there yet. I notice that what he does is a series of different actions (pockets, contours, etc., with two different end mill types). In my case, I’m probably looking at two pocket routines back to back but with different sized end mills of the same kind. The second pocket appears to just repeat the first as an air print for most of it. I don’t see any special steps he took to suggest it be progressive in some way, so I have to assume it’s the different actions? I would expect my repeat pocket at 1/6th to focus on the edges and the bottom of the existing pocket, but I’m seeing a full repeat at smaller steps, most of which represents no contact with the stock whatsoever.
Thoughts?
Google rest machining and fusion 360 that should point you in the right direction.
I’ll head in that direction. That’s a new term for me. Thanks!
I think this one covers it…https://www.youtube.com/watch?v=YRQRXDBTINQ
Check at about the 7 minute mark of the video…
Thanks. I think I am on my way now. I’ve built a new version of the job I previously did entirely with 1/16th using 1/8th to clear a lot more of the larger areas faster.
At first, I thought the “derived operation” was possibly a key, but it seems even just duplicating the previous job and changing the tooling while turning on Rest Machining achieves the same. I’ll research that some more, though, to make sure derived operations don’t carry other benefits.
The first few attempts at using rest machining kept resulting in “no tool path” warnings… it was acting like the 1/16th had nothing to clear the 1/8th hadn’t already done. I knew that couldn’t be true. I even told it to leave stock and tried a 1/4th that could clear next to nothing in that space, yet the 1/16th rest machining operation kept saying “nope, nothing for me to do”. Digging in the documentation, I found that I needed to declare the size of the PREVIOUS tool in the rest machining, not the current tool. I guess that makes more sense, too, as it would otherwise just fill in the current tool size itself. I’m still questioning my accuracy there, but I now do have what looks like a proper tool path to refine and clear only what 1/8th can’t reach.
Logically, I was expecting a sort of sequential chaining relationship you could establish rather than declaring the previous tool size. By that I mean I’d create my 1/8th process, then do a derived operation that is in a way “linked” to the previous operation, but using a smaller tool. That was what I kept expecting, but there might be reasons that’s not the ideal approach.
We’ll see what results I get tonight to compare against the all 1/16th (2+ hour cutting time) version as my baseline.
I’m glad you are getting there. It should save a lot of time.
So an update on my discoveries: The Rest Machining version of my job cut like crap. Whole sections were simply not carved, so I started looking more closely at Fusion 360 and the simulation and realized that it did cut everything it was told. I tried a ton of different tweaks, but the tool paths definitely had huge gaps in them. There was no air cutting, but it also wasn’t doing everything in 1/16th that 1/8th missed. This is all based on 2D Pockets.
I found a discussion on the Fusion 360 forums asking a similar question and found out that 2D Rest Machining does very little in the way of progressive cutting… it seems, either by design or whatever, to do a lousy job of actually achieving this. The example I read showed a 2D job converted to 3D milling and, in that case, the Rest process looks to be dead on precise. I don’t really NEED 3D milling for this, but I’m trying it just as a learning process and to compare. The way I’m doing it isn’t saving me any real time over doing it all in 1/16th with 2D pocket milling… but it’s an interesting learning process. Also, 3D Rest Machining is more a match to what I had envisioned before learning about the process: you selectively tell it to do milling relative to the previous process, etc. 2D just, basically, Rest on or off and, as I stated, it really doesn’t seem to truly analyze the interrelationship of cleared material very thoroughly.
I’m here watching it cut now and seeing it do something I puzzled over in the planned tool paths that don’t understand: these really long, drawn out path-based ramps. Helical ramps I get and I end up with a lot of those… but it’s spending a HUGE amount of time air-tracing whole sections of the geometry while slooooowly dropping on the Z until it plunges in somewhere along the path, cuts a short segment at the full 2mm depth and then hops out to do it all over again. This seems super inefficient if the idea is to have the most contact between mill and stock possible.
Any thoughts on the purpose of this ramp method?
Thanks!
