Compressed air is very, very useful on the milling machine. The tool changer uses air for fast tightening and release. And I often use air to clear the field of swarf, and shavings (yes, I use my mill for wood too).
Recently, at the suggestion of Stuart L of stusshed.com fame, I installed 2 semipermanent nozzles on the mill, with adjustable direction and pressure adjustments. It has been a quantum leap improvement.
The pic shows the jets aimed during CNC end milling of wood. The wood shavings are blown away which makes it easier to see how the milling is progressing; blows them away from me which is safer and cleaner; and stops the chips being machined into the work, which leads to a cleaner cut. It also improves any video or photo of the progress. It must also cool the cutter, although not as effectively as a liquid coolant. I have not tried using the misting attachment, which would improve the cooling, but at the cost of dampening the area and the work.
I particularly like the improvement experienced when machining brass or steel. The swarf is removed from the advancing cutter, preventing it being re-machined and squashed into the workpiece. I am noticing better surface finishes. I also adjust the air direction to keep the swarf away from me; particularly valuable when brass needles otherwise would be flying at me.
When cutting pockets, the air keeps the pocket free of swarf, and when using tiny endmills at high speeds I am experiencing fewer tool breakages.
This gadget was inexpensive ($AUD12) from China. It does not work the compressor too hard when the volume is turned back as far as possible, but still adequate. Although there are 2 jets, I find that only one at a time is adequate.
As an afterthought. I rarely use coolant on my lathes, but an air stream on the cutter and workpiece would probably have similar advantages to those listed above. I particularly wonder if it would assist during deep parting… always a tense procedure. I suspect that the cutter becomes hotter and expands more than the workpiece parting slot if there is no coolant. I will mention the result of air cooling and chip clearing on the lathe in a later blog.