Milling a hole (conversational) and hole creeps

[Muzzer]

There's a commendably detailed manual for all the Wabeco milling machines and accessories here https://www.wabeco-remscheid.de/media/c ... -engl.pdf

The max "rapid traverse" speed is specified in there as 1200mm/min (page 31). I would interpret "rapid traverse" as unloaded positioning, rather than cutting (loaded) feed rate.

Perhaps the solution is more subtle. To achieve such a smooth surface as we see in the pics, the tool must have been moving along the toolpath at quite a pace but with a very low vertical feed / ramp. That's not really the recommended method. Rather, take a decent cut (perhaps 0.02 - 0.05mm per tooth radial or per rev vertical), then go for as deep an axial engagement as possible, up to several times the diameter. I often use 30mm or so axial engagement (step down) on a 10mm cutter. This makes better use of the cutter (improving its useful life) and stands a chance of actually using some decent fraction of the available (2kW?) spindle power. These modern adaptive toolpaths are designed to use your machine that way.

The feedrate should be determined by multiplying the feed per tooth x the number of teeth x the spindle rpm. The rpm is determined by following the recommended cutter surface speed.

Looking at the numbers given earlier in the thread, I'm seeing as much as 1mm / rev feedrate(!!), which is a feedrate of 0.33mm/tooth (1500mm/min and 1500rpm). Conversely, as mentioned above, the stepdown must be prize winningly small. I can't imagine where these values came from but they should really have come from the cutter manufacturer - did you just make them up?

I use a 3 flute 10mm cutter for most of my aluminium work and on the last job I ran 420mm/min feed, 2800rpm, 25mm stepdown and 0.05mm per tooth - these are fairly conservative values that could be increased quite a bit if I could clear the swarf safely. The no-engagement feedrate was 1000mm/min. The spindle load was somewhere around 1kW, so I'm not pushing it.

Try calculating sensible feeds and speeds like the rest of us and I suspect many of these issues will disappear.