Here is a link to a thread from a while ago if you missed it:

I think you need G54.4 I was under the impression G54.2 does not support full five axis (ie G43.4) and you had to use G54.4. Maybe someone else can chime in....but i have used G54.4 and G43.4 together successfully on a variaxis i-700 before.

That would be correct. You might try doing a standard Y move and use it to cheat the code or a Y pecking move with a drill if you want to peck the tool to cheat the code.

Yeah, I call them Nintendo programmers. It's not that they are not smart, they just lack the experience.

Sandvik has new CBN grades, specifically for interrupted cutting. I just watched a video on LinkedIn yesterday that demonstrated cutting gears with the interruptions of the teeth. Grades 7125 and 7135 designed for interrupted cutting.

I made a quick little video. Hope this helps.

I mean, that's only 13:1, Depth to Diameter, on the finished feature. Piece of cake, right? That would be a difficult slot, in Aluminum. In Inconel 718? oof... I'm with Peter, I would drill out as much of that material as possible, without letting the holes intersect. Then I'd look at getting a .047 diameter endmill, from Harvey Tool, and have them relieve the neck. I would get at least 3 different lengths of tools to finish the slot. If you try to go with a single "length" to rough and finish, you'll be there for days. I'd go with a 5X (.250 to shoulder), and a 10x (.480 to shoulder), and get an additional 10x cutter, that is ground back to .658 to the shoulder. ( 14:1, D2D, on a .047 endmill) I'd look to finish with at least a couple different lengths of tool. For the bottom of the slot, I'd try a 1 mm diameter, with 1 mm length of cut, and 17:1 D2D. You could try something like a 1.25 mm diameter (.051), and try to interpolate a slot that is .0004-.0008 wide, to stay under your .055 width tolerance, but what a pain. You'd be far better served by drilling out as much material as possible, and just sending it off to get burnt out on the EDM. As slow as EDM is, you will get the part finished much faster than trying to dial in a slotting process with multiple tools that are extended way beyond the practical limit.

You didn't mention if it was blind or a window? It is possible, but depending on the tolerance and surface finish it might be more hassle than just making an electrode and burning it. Burning it will take longer, but at least you can just set it and forget it on the sinker instead of fiddle farting around worrying about hotdog endmills in Inconel.