Rapid collision with Stock
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report
I'd like to preface this post by stating that I've scoured the forums on this and can't find an answer that addresses my issue. I'd also like to say that before anyone asks, I cannot share the file that is giving me trouble. I'm trying to reproduce the issue in a test model to be able to share it, but I figured I'd see if anyone here knew right away that I was doing something dumb. I have taken some screenshots to try to help explain the problem. This is going to be a long post, so I'll get right to it.
I am running a 3D Adaptive Clearing toolpath which calculates in at around two hours machining time (down from over four and a half hours on a different CAM Package. Gotta love that Adaptive Clearing!). This is my first (of two) operation(s) in this file. Upon generation of the toolpath, fusion also generates somewhere between 160 and 900 collisions with the stock, despite the fact that my tool holder never comes in contact with the part and my maximum step down is set to 15mm (0.591") from a tool flute length of 19.05mm (0.750").
Many of these collisions were due to an apparent bug in Fusion's tool [library and/or tool simulation model]. When setting up my tool (a 1/4" dia., 3 flute carbide end mill with 3/4" flute length, no shoulder, 1/4" dia shank and 4" OAL with 2.15" body length), I set the shoulder to 1", because it didn't have one and 1" was longer than the flute length. I figured that because the diameters were the same, Fusion's kernel would ignore the shoulder completely. I was wrong, and when running the toolpath for the first time, fusion was stepping down into the second stepdown pass and trying to cut beneath material it hadn't cleared the first pass. Shouldn't have been possible to generate that and call it a valid toolpath, but it tried. Thankfully it was just around the machining boundary and the cut was in foam, so when the tool shank hit the material, it burnished/melted/ripped it off instead of breaking my tool and destroying my machine.
Checking the forums for that error, I found a post where someone stated that if you have no shoulder on your tool, then shoulder length should be set to the body length (for me, 2.15"). I did this, and inexplicably [to me], fusion immediately generates a toolpath minus over 500 "tool shaft collides with stock" errors. So despite the flute and shank diameters being equal, Fusion is somehow unable to take the tool shank into account if the shoulder isn't fully defined. Even if you don't have a shoulder on your tool...
Anyhow, on to the next issue. I still have between 30 and 500 collisions in my toolpath, depending on how I generate it. All of them now appear to be "rapid collision with stock" errors. As you can see in the pictures below, Fusion is generating rapid plunge moves. It's a bright yellow line indicating a rapid move straight down into the material, ignoring my plunge feedrate (600mm/min vs. a rapid feedrate of 6000mm/min). I haven't checked them all to see if they're all plunges, but I'll assume most of them are, because when I increased my stay down length and priority, I'm generating hundreds fewer collisions with my toolpath.
I could understand if there were a previous operation here which should have removed the material, but there's not. I'm machining from modeled stock the exact same size as what's on the bed of the machine. The only thing I can think of is increasing my vertical lead in as another post suggested, but one, that's a workaround, not a solution, and two, I'd presumably have to increase my vertical lead in to greater than my stock height of 2". Besides being a ridiculous idea, it would likely increase my machining time by several hours at the least.
Anyway, I know I haven't given you all a lot to go on, hopefully someone can immediately point at something I've said and tell me, "you're doing it wrong, dummy!" I will try to reproduce this in a file that I can share and post it here. Thanks in advance to a great community here!
Fusion