# Machining Coolant or Cutting Fluid?



## ACHiPo (Nov 23, 2017)

Why do CNCs seem to hose down parts with cutting fluid (especially when they are fully enclosed)?  Is it just because CNCs typically hog out material at a higher rate?


----------



## Mitch Alsup (Nov 23, 2017)

ACHiPo said:


> Why do CNCs seem to hose down parts with cutting fluid (especially when they are fully enclosed)?  Is it just because CNCs typically hog out material at a higher rate?



CNC machine spray down the part under machine to remove chips (surface finish), cool the tools (life), cool the part (dimensional stability).


----------



## ACHiPo (Nov 23, 2017)

How is that different from what’s needed for manual milling?


----------



## Tozguy (Nov 24, 2017)

ACHiPo said:


> Why do CNCs seem to hose down parts with cutting fluid (especially when they are fully enclosed)?  Is it just because CNCs typically hog out material at a higher rate?



Yes. CNC machines are generally more productive to make the extra investment over manual machines worthwhile. So more heat, more chips and expensive tools have to be managed.


----------



## ACHiPo (Nov 24, 2017)

Tozguy said:


> Yes. CNC machines are generally more productive to make the extra investment over manual machines worthwhile. So more heat, chips and expensive tools have to be managed.


Thanks.  Where would I find out maximum dry speeds/feeds/depths without flood or mist coolant?


----------



## 4GSR (Nov 24, 2017)

ACHiPo said:


> Thanks.  Where would I find out maximum dry speeds/feeds/depths without flood or mist coolant?


Take the existing numbers and cut in half or if you feel that is too much, drop the numbers by about 33%, then work up from that for dry turning.


----------



## ACHiPo (Nov 24, 2017)

4gsr said:


> Take the existing numbers and cut in half or if you feel that is too much, drop the numbers by about 33%, then work up from that for dry turning.


Thanks!


----------



## Tozguy (Nov 24, 2017)

For dry machining you have to read the chips to get the right settings as explained in the video on chips feeds and speeds from this source 
http://www.thatlazymachinist.com/free-training.html


----------



## Wreck™Wreck (Nov 25, 2017)

ACHiPo said:


> Why do CNCs seem to hose down parts with cutting fluid (especially when they are fully enclosed)?  Is it just because CNCs typically hog out material at a higher rate?


Because you can with an enclosed machine. There are few operations that will not benefit from flood coolant.

Also enough coolant will blow the chips out, there is nothing more damaging to mill tooling then recutting the chips.

As a simple example I did this on Saturday, if done without coolant the material would glue itself to the tool causing all manner of problems.


7" diameter aluminum saw cut rounds that finish with a 3" bore 3 1/4 inches long. I chose a 2 11/6" spade drill and had at it, without coolant I would have been doomed. 1 minute 45 seconds per hole in 25 parts.
Flood coolant is your friend. Do not try this at home, that is a 30 HP spindle machine.

I can not overstate the usefulness of flood coolant


----------



## ACHiPo (Nov 25, 2017)

Wreck™Wreck said:


> Because you can with an enclosed machine. There are few operations that will not benefit from flood coolant.
> 
> Also enough coolant will blow the chips out, there is nothing more damaging to mill tooling then recutting the chips.
> 
> ...


Wreck,
Pretty compelling case.  I was questioning "spade bit", then I looked closer--by golly you've got a hardware store spade bit clamped in some sort of boring bar.  I don't doubt the efficacy, I just don't want to deal with the mess.  Mebbe I'll get over it, but spraying white oily stuff everywhere (well, you only spray it one place but it ends up everywhere) and then separating the chips seems, em, messy.

Evan


----------



## Bob Korves (Nov 25, 2017)

Flood coolant is a great thing to spread all over your employer's floor while getting paid for it, and then get paid to clean it up.  In a home shop, the mess is all yours and you own it...

I hooked up my mister for the first time today, to my surface grinder.  I am in love with that already, much better finish, flatness, and size, and not a drop of coolant on the floor.


----------



## ACHiPo (Nov 25, 2017)

Bob Korves said:


> Flood coolant is a great thing to spread all over your employer's floor while getting paid for it, and then get paid to clean it up.  In a home shop, the mess is all yours and you own it...
> 
> I hooked up my mister for the first time today, to my surface grinder.  I am in love with that already, much better finish, flatness, and size, and not a drop of coolant on the floor.


Bob,
My sentiments exactly.

Nice that the mister us helping.
Evan


----------



## Wreck™Wreck (Nov 26, 2017)

ACHiPo said:


> Wreck,
> Pretty compelling case.  I was questioning "spade bit", then I looked closer--by golly you've got a hardware store spade bit clamped in some sort of boring bar.
> 
> Evan


Actually it is a carbide inserted spade drill as seen here, through coolant that I didn't use because it is a PITA to set up for a few dozen parts.
https://www.mscdirect.com/product/details/79731097

They work a charm if one has the power and are not terribly expensive even by hobbyist standards.


----------



## Dan_S (Nov 26, 2017)

ACHiPo said:


> How is that different from what’s needed for manual milling?


It's beneficial for manual milling and turning as well, but most modern CNC machines are capable of way higher material removal rates than a manual machine. For example Haas's smallest Mill has a 7.5 horsepower spindle motor.


----------



## ACHiPo (Nov 26, 2017)

Dan_S said:


> It's beneficial for manual milling and turning as well, but most modern CNC machines are capable of way higher material removal rates than a manual machine. For example Haas's smallest Mill has a 7.5 horsepower spindle motor.


Holy cow--I knew that Haas could hog out material, but I had no idea how much power they had.  No wonder the enclosure looks like a shower door when they're running.  I have no interest in running that fast, but then again I'm not in this to make money, just to have fun.


----------



## Dan_S (Nov 26, 2017)

ACHiPo said:


> Holy cow--I knew that Haas could hog out material, but I had no idea how much power they had.  No wonder the enclosure looks like a shower door when they're running.  I have no interest in running that fast, but then again I'm not in this to make money, just to have fun.



That's a baby machine a lot of cnc machines come with 30HP spindles. As you can imagine they can quickly generate a lot of chips and a lot of heat.


----------



## ACHiPo (Nov 26, 2017)

Dan_S said:


> That's a baby machine a lot of cnc machines come with 30HP spindles. As you can imagine they can quickly generate a lot of chips and a lot of heat.


The more I learn the less I know...


----------



## Wreck™Wreck (Nov 28, 2017)

Bob Korves said:


> Flood coolant is a great thing to spread all over your employer's floor while getting paid for it, and then get paid to clean it up.  In a home shop, the mess is all yours and you own it...
> 
> I hooked up my mister for the first time today, to my surface grinder.  I am in love with that already, much better finish, flatness, and size, and not a drop of coolant on the floor.


These parts are a chip nightmare. I am removing 8 pounds of material per part, pushed the feed and speeds until the chips were under control and left it run unattended, working well so far. 970 FPM on the OD work and 450 FPM on the ID operation, these machines do not have CSS control which causes problems.


----------



## Bob Korves (Nov 28, 2017)

Wreck™Wreck said:


> These parts are a chip nightmare. I am removing 8 pounds of material per part, pushed the feed and speeds until the chips were under control and left it run unattended, working well so far. 970 FPM on the OD work and 450 FPM on the ID operation, these machines do not have CSS control which causes problems.


Wreck, I am in awe of the heavy machining and large lots of parts you turn out.  Very nice work, and please keep posting them.  Most of us hobby guys never do anything like that.  Still, it is nice to know some of your techniques and tricks in case we ever need to borrow it.  But really, for most of the work I do, the techniques, tooling, machine size, and just about everything else needs to be different, simply because of the different stuff I have to work with and the projects I am making.  Again, please keep showing us the work you do, great stuff!


----------

