[joeavaerage]

Hi,

Many say that air cooling is the best way to go even better then flood.

Disagree.

Particularly with plastics, but any material that is prone to sticking to the tool, say aluminum, the real game changing solution is to flush the chips away from the cut-zone. Lubrication and cooling is nice,
but most importantly clear the chips so they don't get re-cut.

When a chip is cut it gets hot, well at least warm, as a good fraction of the energy of cutting has gone into the deformation of the chip. Lets say the temperature of the base material is T₀ then the
temperature of the chip is T₁ and the difference is say 20⁰C. If that chip get recut then its temperature will be T₂ and will be 40⁰C higher than T₀,
and if it gets cut a third time T₃=60⁰C and so on. Very soon the chip or fragments of it a damned hot and just set to stick to the tool. If you flush the chip away so that it does not get
re-cut then that temperature rise is insignificant.

For the purpose of moving a chip from the cut-zone a fluid is way more viscous and way heavier than an air blast. If the velocity of the air blast is high enough then it too will move the chip. Any shadowing
of the air jet by the tool or base material will reduce the effective velocity sharply.

Both will work but air blast requires very much more precise control to be effective. Find rcaffins posts about it, he does it with air blast and described the results.

Craig

[peteeng]

Hi - My view is that if you have done it both ways and can make an accurate assessment then we all learn something. Mills with enclosures have flood, if you have flood then no need to experiment with anything else (unless environmental rules for coolant disposal change that) . But routers with no enclosure this becomes difficult. So air and ethanol is a common solution. Cold air and ethanol maybe a very good solution. Cold air maybe all that's needed these days with coated tools and better understanding of cutting conditions... Peter

[metalmayhem]

A mister would probably be the best solution under the circumstances . A concentration of water and liquid dish soap is plenty good for keeping plastic lubed . Normally I'd say flood would be best but I'd quickly rule it out after looking at the router and the mess that would follow . Even a soapy spray bottle in one hand and an air nozzle in the other hand will suffice , just give it a shot every so often

rpm can work for or against a guy . Often a simple solution to reducing friction and meltdowns is to reduce rpm and increasing the chip load .

[joeavaerage]

Hi,
I think cold air is a waste of money....you don't need cold air, just a well directed jet of high velocity air will clear the chips. Cooling and lube are way down the list, nice to have but they do not
in themselves create the solution......its getting rid of the chips that is the priority. Whether you use air, water based coolant, just plain water or even pure oil does not matter so long as it prevents the chips from being recut.

If you think a handheld air nozzle is the answer....good luck to you. It works only so long as you are vigilant. The moment your concentration wanders then the chips get recut and stick to the tool, marring the job and/or
breaking the tool. How do I know?.....I tried this repeatedly myself, with patchy results. Then I tried a fixed nozzle, better but no prizes. Then I tried 4 fixed nozzles, better again. Then I tried flood, and that was the first and real breakthrough.
It took me the best part of a year messing around with air before I got to trying flood....but that's what I did, and these are the results: Air is good if you have plenty of volume at fairly high pressure, say 50psi or better, and can use multiple nozzles
to ensure that at all times the chips are being cleared.Any interruption to that clearance of chips invites disaster.

Craig

[metalmayhem]

Hi,
.
If you think a handheld air nozzle is the answer....good luck to you

I'm not a one trick pony and I've done it many times in my career under many applications , I wouldn't have suggested it if it doesn't work . Maybe its not a full time solution , but for the time being it beats gallons of flood coolant on the floor and all over a wood router . A lot of people use air blast , I don't but a lot do successfully . Just because it failed for you doesn't mean it doesn't work

recut chips don't necessary add up to broken tools , especially on plastic . Usually it causes poor surface finish . Can it be a factor yes but it's not the be all and end all . Look at the depths of cuts being used here and the chip loads , thats hardly what a guy can call chips and random air blasts is enough to get that out of the way . The reason I suggested mist is the fact that there is air available as well as lube . It's an effective and cheap solution , and soap cleans up better than oil .

[joeavaerage]

Hi,

I'm not a one trick pony and I've done it many times

Neither am I.

Recall I said:

It works only so long as you are vigilant.

With heat sensitive plastics like PE and ABS you have a few seconds to clear the chips before they adhere to the tool, and it goes downhill from there. Fixed and multiple fixed nozzles are better but still not 100%.

Recall I said this also:

Air is good if you have plenty of volume at fairly high pressure, say 50psi or better, and can use multiple nozzles

So, I'm not saying it does not work, but air is not infallible. It rather depends on how sensitive OP is to a failure. If a job turns out marred because of a tool build up, does that screw up an important
piece of material?. If each and every piece is important you need a 100% solution...and I was never able to get 100% with air, 90%-95%, but not 100%.

Craig

[metalmayhem]

Hi,

" If a job turns out marred because of a tool build up, does that screw up an important piece of material "

Craig

it was more about tool breakage wasn't it ? . I don't recall finish being brought up until I mentioned it , nor do I recall stating that it's perfectly fine to have a part covered in crap , To answer your question - Isn't this what finish passes are for , no one should rely on rough passes for a decent surface finish . Clear the sh%$ out of the way for a finish pass , not hard to do , even if a guy has to add an m0 before doing so

if each piece is of great importance , then having the right machine for the job should be top priority , but thats not the case here . Because of the machine style (wood router) it is impossible to reasonably run flood coolant . Most guys with similar setups use mist or an air blast at the minimum . A mister properly set up will help push away chip and strands as well as add a light coat of lube and the air will help cool things . Doesn't mean a guy should walk away from a machine and hope for the best , which should never be the case .
Tool breakage on plastic tends to be caused by meltdowns , it's about friction . A lack of lubrication causes friction , a lack of cooling accumulates heat . As I stated previously rpm isn't always our friend and often a lower rpm is much better . Every plastic is different but this stands for a lot of materials

[FredLed]

Cool! From what I have read on the emastercam link, a mix of air blast and very little coolant is the most universal solution. (maybe a drop from time to time in front of the air gun tube, or inserted into the airgun tube). So little that you won't have to clean after. Or maybe by pouring a few drops on the material along the trace and on the tool before routing, until you install a more advanced system.

[FredLed]

A radius around the corner is a shorter path and accomplishes the same thing. Shorter path means less time. A shorter path hundreds of times means a lot less time.

Theoricaly yes. In practice it was very slow because each coordinate slowed the machine somewhat. In a case where the quarter circle was composed of multiple coordinates. Maybe it's faster using G2 or G3 code but I din't try it yet on external angles.

[FredLed]

Even a soapy spray bottle in one hand and an air nozzle in the other hand will suffice , just give it a shot every so often.

This looks scary to me, for safety reasons. I would never come close to the spindle when the tool is spinning.

I have googled for cnc mist spray and it seems that there are various solutions including inexpensive DIY ones.

[metalmayhem]

it can be done from a few ft away but if you not comfortable with it then it's best not to do it

A cheaper mist setup is all you'd need , with the addition of a pop bottle to hold your coolant , soap or whatever , and a half decent compressor . Even with this it will still require the use of an air blast every so often to clear away the cuttings . As previously mentioned - a constant air blast is the easiest solution but it requires a beefy compressor otherwise it will starve for air . I know I stated I don't use it , but , I have used it on plastics where flood coolant failed to wash away the stringy crap . I just don't like the constant noise . Mist will have a constant air noise as well but it's not as bad