Crazy Idea...

[twocik]

Might be a dumb idea, but was thinking about his today. Well I thought about how to keep tools as cold as possible to reduce wear, melting material to the cutter and maybe even a better finish.


Has anyone experimented with freezing the raw aluminum stock before use or maybe even dry icing it ?

Or maybe even hooking up dry ice coolant lines of some sort...


.

[Magnum164]

I am not sure, would need a materials person to verify. But depending on the material the process of freezing could make it harder and therefore would not be a big benefit. Think of the extreme of what happens when you freeze water...

Just like when you heat a material it softens up (while under heat).

Now hook a Peltier device up to the spindle and super cooling the cutter might be something interesting to try

[Don Clement]

Ditto what magnum said. Also materials change dimensions with temperature. BTW aluminum changes at twice the rate of steel and that change is inch/inch so larger diameter and longer parts will change more than smaller parts with a change in temperature. Although I have build a few projects using Peltier devices (one was a 4 stage Peltier device) I use a Vortec 610 cold air gun http://www.vortec.nl/fileadmin/Image...r_Guns_eur.pdf on my lathe, bandsaw and manual mill. The Vortec is not as efficient at removing heat as flood cooling though, but a lot less messy when used on manual machines without flood coolant shielding. The Vortec 610 can give up to a 40*C decrease in temperature. A 32*C change from ambient can be seen here as shown using T type thermocouple to measure the air gun output:
http://s72.photobucket.com/albums/i1...minus7degC.jpg
It does keep my 5hp 2-stage air compressor going continuously as it requires 15SCFM @ 100psi to run.

Don

[twocik]

Ahhh that's right magnum, I forgot when cooling/heating metal it changes size...

What about making some sort of water cooler we could stick into our tanks or at the end of the hoses ?

[Magnum164]

Ahhh that's right magnum, I forgot when cooling/heating metal it changes size...

What about making some sort of water cooler we could stick into our tanks or at the end of the hoses ?

Question is what is the operating temp range of the coolant being used? if you cool the coolant down too much the pumps may have a hard time pumping it.

I don't do that much machining at the moment to worry about heat. But if the coolant temp is a problem you can always run through a radiator like I do my PC.

[Pergamon]

twocik, interesting idea! A few thoughts of mine for your reference -

First off I get a little bit nervous when you say “keep tools as cold as possible”, hehe…the reason is that an extreme low temperature can reduce the material elasticity dramatically. Dry icing may not be a biggie as its only -70F, say, but If you pour liquid nitrogen to some cutter for instance, it can make the cutter surface brittle – something you don’t wanna see happening, lol. Also, as people mentioned above and I agree with, a high temperature gradient (assuming you are trying to cool the cutter down in some form while cutting) can cause deformation and thus worse stress concentration. So I can see that the cutter might wear even faster than its not cooled or simply coolant-cooled.

But speaking of dry-ice, I’m thinking there must be some better liquid that has a bigger capacity or lower temperature while it still maintains its liquidity so it pours or drains more easily than solid…something to ponder. Hope this helps a little

[307startup]

Dry ice is already a medium for cooling machine tooling. Google it. The issue becomes evacuating the fumes, as it displaces oxygen. Not helpful to the operator at all

Several materials machine better when cooled...delrin, polyethylene, UHMW HDPE, nylon, teflon, etc. The issue becomes machining to size before the material warms up due to friction.

As an interesting side note...proper cryo-treatment of HSS endmills, cobalt endmills, even carbide and ceramic inserts show a 2-5x increase in life.

[300sniper]

As an interesting side note...proper cryo-treatment of HSS endmills, cobalt endmills, even carbide and ceramic inserts show a 2-5x increase in life.

i am pretty sure a local cryo guy found that it does the same to disposable razors.

[Don Clement]

Wouldn't it be better to use a closed loop with cooling fluid so that machining could be kept at a constant temperature such as ambient? That way there would be no dimension change in the material when machining. Same goes for spindle cooling, a closed loop system that would keep the spindle temperature constant. Different types of fluid (water is very effecient at removing large amount of heat) could be used. Also air could be used. I have worked some with a closed loop air driven systems for testing semiconductors such as this system http://www.bridgetec.com/kinetics.html Seems like for machining such a closed loop system with air might just work with out the mess of flood coolant. BTW I used a sort of manual feedback closed loop temperature to set the bearing preload on my Sherline 10K rpm spindle with a self-adhering T type thermocouple probe on the spindle body http://www.omega.com/ppt/pptsc.asp?ref=sa1xl I measured the spindle temperature and adjusted the bearing preload until a prespecified temperature was reached for 10K rpm. This sort of manual feedback closed loop appraoch might also be used for machining cooling and spindle preload on the Tormach.

Don

[R.DesJardin]

Ok, this sounds like someone doesn't want to use coolant which is a proven way to do what is needed.
So is your machine in a basement or a ultra clean garage where coolant would make a mess?
I use coolant, it can be messy, it's in my shop, it gets messy, I manufacture stuff, it's in a shop. Coolant works.
I would think that using air would take quite a good compressor to keep up if you are doing any length of cut time.

[Magnum164]

Ok, this sounds like someone doesn't want to use coolant which is a proven way to do what is needed.
So is your machine in a basement or a ultra clean garage where coolant would make a mess?
I use coolant, it can be messy, it's in my shop, it gets messy, I manufacture stuff, it's in a shop. Coolant works.
I would think that using air would take quite a good compressor to keep up if you are doing any length of cut time.

I think the discussion was about alternative solutions. Nothing was said about coolants being messy.

For the record, yes my machine is in a finished basement. My coolant is CONTAINED within my enclosure. So no mess.

But doesn't mean we can't discuss alternative solutions. That's how innovation is kept alive

[Magnum164]

Wouldn't it be better to use a closed loop with cooling fluid so that machining could be kept at a constant temperature such as ambient? That way there would be no dimension change in the material when machining. Same goes for spindle cooling, a closed loop system that would keep the spindle temperature constant. Different types of fluid (water is very effecient at removing large amount of heat) could be used. Also air could be used. I have worked some with a closed loop air driven systems for testing semiconductors such as this system http://www.bridgetec.com/kinetics.html Seems like for machining such a closed loop system with air might just work with out the mess of flood coolant. BTW I used a sort of manual feedback closed loop temperature to set the bearing preload on my Sherline 10K rpm spindle with a self-adhering T type thermocouple probe on the spindle body http://www.omega.com/ppt/pptsc.asp?ref=sa1xl I measured the spindle temperature and adjusted the bearing preload until a prespecified temperature was reached for 10K rpm. This sort of manual feedback closed loop appraoch might also be used for machining cooling and spindle preload on the Tormach.

Don

I think closed loop would be fine. When I was talking a radiator and cooling I was thinking more of cooling the coolant back to ambient. I think cooling beyond that would introduce just more complications. Granted with a closed loop you are going to need a really good filter system to keep the swarf out completely. So as you build in one area, it complicates another

Even if you use something like a peltier, the opposite side is heated, so you have to move the heat out of the area or you increase the room temperature as well.

Then again. You could always set a little portable fridge beside the machine, plumb the coolant tank and pump inside and you have can adjust the cooling effect on your coolant by simply adjusting the fridge temp or the time the coolant spends in the fridge Would be interested in knowing the temp change in coolant when doing a lot of machining.. I am not at that point, just made a few simple parts for my lathe.