I'm running the skateboard truck parts today, and it was quite a learning experience.
I double and triple checked over each aspect of my program before running anything to ensure I didn't crash the machine. And my boss instructed me to run the VF2 at 5% rapid and 50% feedrate with my finger hovering the feed hold button to catch any possible errors.
I'm happy I did too because once I roughed out most of the material, I had a pretty close call. What happened was the trunnion angled at 120deg, this meant that the backside is higher than the rest of the 5-axis addition, in such a way that when the spindle carriage came down, it would smash into it before the endmill could touch the stock. The solution was to use a more extended tool holder, which I ended up doing and got a few extra inches of reach. Even with a 7" extension from the spindle (I had 3" previously), it came too close to hitting the trunnion, and I was not very comfortable with that. Since the cutter was hanging so far out, the vibrations of the endmill would be so violent to such a degree that it would require a very long cutting operation (taking super small stepdowns with very slow feedrates to prevent any marring of the surface.)
After discussing it with my boss, he suggested a much easier way to clear out that cavity and shorten the run time significantly. He said to use keyseat cutters (aka keyway cutter) to cut along the flat faces, allowing perfectly flat surfaces in a single toolpath. Previously I planned to rough it out with a large square endmill, then come in and finish it with a smaller ball cutter, with the runtime being upwards of 16 minutes for the whole setup. Using keyseat cutters, I could simultaneously remove the material and finish the grooves simultaneously with a radiused corner tool, and runtime would only take five minutes. Doing it this way, I didn't have to reach any sketchy angles as I would cut side to side instead of up and down, so my 120deg angle turned into 30deg! I ran it and am quite shocked at how good the results were!
Once I finished the sketchy cut, I was just about to let it do the tool change and move on to the next toolpath. However, I noticed the trunnion was still at that very steep angle, and if I went through with it, the extended tool holder would collide with the a-axis bed. Once again, I was am glad I had my finger over the feed hold button and prevented a major disaster! I never really realized it before, but when doing the tool changes, it raises the z-axis as it should. Still, it doesn't home the A and B axis, it usually wouldn't be an issue, but if you had to work on weird angles, it becomes a massive issue, one that you can't ignore. The solution, of course, was to add a homing sequence to the beginning of each tool change.
I wasn't entirely sure how to do this to make it easy to add the code to my future programs and went first to the post-processor to see if I could figure out where to edit it. I wasn't able to find what I was looking for from looking at the straight code, so I just googled it to see if it was a common problem. I found a few posts of edits people made to their post-processors but nothing for my situation. The next best thing was to manually add the code in the Manual NC section of Fusion360 CAM; I could type in the G-code for the homing sequence. The neat thing about this is that it acts like a toolpath in the sense that it's got a moveable tab where you can line it up in between operations or before tool changes. The downside is that it is it's own unit, meaning you have to add it in each time manually, and doesn't do it by default. It's more of a hassle thing than anything else. My goal is to program it directly into the post-processor so I won't have to remember to add it to each program.