Re: [CAD_CAM_EDM_DRO] Question on coolant vs lubricant when milling & the need for each

glee@... wrote:

> I'm trying to get a clear understanding of the need for coolant vs
> lubricant when milling.
>
> In my scenario, I am using a Sherline Mill, cutting aluminum with a 3/16 or
> 1/4" end mill. I tried using a 1/8" cutter but that was a disaster so I'll
> stay away from that for a while.
>
> Now that you know what I am cutting here's my question:
>
> Am I correct in my understanding that the primary objective of any cutting
> fluid is to both keep the cutter from overheating and also to move chips
> away from the cutter? (Perhaps not in that priority)

Especially in Aluminum, keeping the WORKPIECE cool is also a very
important task. In fact, with carbide or cobalt tools, keeping the workpiece
cool is much more important than keeping the tool cool.

A toothbrush can be used to keep the chips clear of the cutting area,
and sufficient cutting speed also helps to throw the chips out of the
region.

Lubricating the cutting edge is a very tricky thing. You want to prevent the
cutting edge from wearing down, but you also want the cutting edge to
be able to easily penetrate the surface and begin cutting into the material.
Standard lubricants will not be helpful in this. Special additives in cutting

fluids do a good job of this.

> Now, based on my understanding of the above, correct or incorrect, is there
> any reason that I cannot use one of those really neat vortex cooler devices
> with a source of compressed air and keep the workspace clean? This would
> both cool the cutter and bow the chips away. I assume that if this is not
> the proper thing to do that there must be good reason....

Do you have a 10 Hp air compressor (and I don't mean "Sears" HP here,
either)? If not, forget the vortex cooler. they are not efficient, and very
little cooling is actually done at the cutting site. Most of the cold air
just blows on by.

I use flood coolant with synthetic cutting fluid, and it works wonders.

>
> I know that the sherline is a small mill and that aluminum is a soft metal
> as metal goes. Am I making a big deal about nothing given the small size of
> my mill, cutter and block I am able to cut with this size of mill?

Probably using correct cutting speeds in surface feet / minute, and proper
feed rates in inch/tooth are the most important things to do, first. A little

thread cutting oil spread on with a toothbrush or acid brush helps quite a
bit. If doing a lot of work in a small area, check the work for heating, and
allow it to cool between passes (or get or make a flood coolant system).

Jon