1/8" drill bit (3.2mm) at 16000RPM, 5mm/min is a bit out of range. The surface speed is 150m/min (500ft/min), which is a bit fast w/o a flood or through the tool coolant, but not too fa out of the range. The feed is 0.3micron/rev (0.012 thousandth of an inch), which is a very, very light feed. The bit will rub, then grab, then rub, then grab… Without coolant, the bit will heat and dull, then break. Too low a feed will dull and destroy a tool faster than too high a feed.
I’d slow to about 4000RPM (40m/min, or 125ft/min, the low, low end for most aluminum’s, but this is about a three diameter hole depth, so low end is good), bump the feed up to about 50mm/min, and go with about 3 or 4 pecks per hole to clear chips. This will give you about 12micron (0.5 thousandths) feed per revolution, which is still a bit light (about 50micron, 2 thousandths, is recommended by most sources for 1/8" bit), but in the range for a continuous cut so the chips take the heat out. The pecks should retract to clear chips when the drill has cut roughly the drill diameter or a little less, and as the hole gets deeper than about three times the drill diameter, more often to reduce heating and wear from rubbing. 8000RPM would be right in the groove for a 1/8 drill, but the feed might be excessive for the machine, especially with the need to peck.
Others with better knowledge of the machine may have a different view (I have a nomad, not a shapeoko), but I think machine rigidity and the spindle are your limiting factors here. If you can not slow the spindle, then you are looking at feeds in the range of 200 to 400mm/min, or you will need a good coolant, or both.