Newbie- In need of Clarifying my Coolant Education

[JWB_Machining]

Originally Posted by Geof Also always use coolant, flood preferably but on a TM-1 you may get a shower so you have to compromise.

We were talking about Machining Aluminium

What is flood and what is shower in terms of using coolant? I know misting is misting the tool and work piece with mistable coolant but what exactly is flood and what exactly is shower? Also what are the benefits and drawbacks of them?

Also I've been told the following:

1)Do not use coolant when cutting steel with carbide to prevenet thermal shock fracture.

2)Use Coolant when cutting alumium with Carbide to prevent sticking.

3)Never use Coolant when cutting with ceramic inserts.

And now more questions What if the Carbide End Mills are Coated with TiCN, are there any special rules for that? What if they're coated with AlTiN? All I know about AlTiN is don't use it on Aluminium. So on top of coolant questions what do these Coatings do?

I beleive TiCN prevents chips from welding to the cutter, so does that mean don't use coolant with them when cutting alumiuim?

-JWB

[Geof]

Originally Posted by JWB_Machining We were talking about Machining Aluminium What is flood and what is shower in terms of using coolant? I know misting is misting the tool and work piece with mistable coolant but what exactly is flood and what exactly is shower? Also what are the benefits and drawbacks of them? Also I've been told the following: 1)Do not use coolant when cutting steel with carbide to prevenet thermal shock fracture. 2)Use Coolant when cutting alumium with Carbide to prevent sticking. 3)Never use Coolant when cutting with ceramic inserts. And now more questions What if the Carbide End Mills are Coated with TiCN, are there any special rules for that? What if they're coated with AlTiN? All I know about AlTiN is don't use it on Aluminium. So on top of coolant questions what do these Coatings do? I beleive TiCN prevents chips from welding to the cutter, so does that mean don't use coolant with them when cutting alumiuim? -JWB

You haven't seen enough of my posts to recognise sometimes I have a less than obvious sense of humor.

Flood coolant is when the tool and workpiece is submerged under a very copious flow of coolant; gallons per minute.

Shower is what you get from the spray as the coolant is flung off in all directions by the spinning tool on an open machine.

1) Yes but sometimes no; this is something that comes with experience, when to use coolant with carbide on steel. With facemills or big cutters taking a stepover less than half the tool diameter maybe coolant can be omitted and an air blast used. Because the cutting edges spend most of their time out of the cut and cooling in the air blast and because this type of cutting can be configured to eject most of the heat in the chips the tool stays cool.

However for a small tool that is taking a cut whichs buries it down inside the material, a deep slot or interpolating a hole, the heat build up on the tool can be detrimental and I find it best to flood the cutting area with coolant. Flooding reduces the chance of thermal shock because everything is constantly under coolant.

2) Yes but it is not just sticking it is melting and deforming and packing in the flute. Another reason to use two flute cutters with more flute space for chips.

3) NEVER NEVER NEVER!!!!!!!!!! The whole operating principle is that they can tolerate extreme heat but little shock or load. Ceramic tools at high speeds heat the chip so much it can become very hot, red hot or brighter sometimes, so it loses all its strength; on steels that is.

On aluminum preferably use uncoated micrograin carbide cutters which can be finished almost to a polish with very sharp edges. Coatings are either redundant or negative on aluminum. Redunant because part of their function is to prevent hot adhesion between the chip and the tool and aluminum does not get to a temperature that is high enough; negative because some coatings have a chemical affinity for aluminum so it simply sticks.

Do a Google on 'coatings on carbide tools' or other search words and you will find a plethora of information.

[coolman]

All those rules is too confusing for a newbie like myself. How about this rule. Use maximum coolant when cutting anything metal (aluminum, steel, cast iron, and etc.). Will I be OK with this simple rule? This is what I plan to do. As far as the cutter sticking to the aluminum, the coolant solution should keep it lubricated, I am thinking.

[Geof]

Originally Posted by coolman All those rules is too confusing for a newbie like myself. How about this rule. Use maximum coolant when cutting anything metal (aluminum, steel, cast iron, and etc.). Will I be OK with this simple rule? This is what I plan to do. As far as the cutter sticking to the aluminum, the coolant solution should keep it lubricated, I am thinking.

If you cannot remember a few principles and rules find something different to do. Although I suppose if you are just doing it at a hobby level you can fumble by, but if you plan on going further get ready to be overrun with rules.

[The Blight]

If you cannot remember a few principles and rules find something different to do

That was a bit harsh. I bet a newbie won't be using ceramic inserts or carbide end mills. There are a few rules when it comes to machining, but most of them make sense.

I just have to say one thing. Try it. If it seems good enough, then go on. If it looks bad, then try switching.

Oh and this is on a hobby level for newbies. Professionals often get information about this when buying the tools.