Machining Coolant or Cutting Fluid?

[ACHiPo]

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]

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]

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

 

[Tozguy]

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]

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]

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]

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]

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]

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]

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 an simple example I did this on Saturday, if done without coolant the material would glue itself to the tool causing all manner of problems.
View attachment 247925
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
View attachment 247926

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