Tool Coatings

[jl123]

I'm shopping around for some new end mills both standard and ball. I'm confused what these different coatings do and whether or not they can be used with coolant. TiCN and TiALN are the two that I'm looking at as I cut mostly aluminum. I read somewhere that TiALN is suitable for dry milling and the heat actually makes the coating perform at its best. Does this mean I can't use coolant? I'm just looking for long lasting/tough cutters. I have a X3 so I'm wondering what I should go with. I plan on using a fog busters coolant system.

Thanks.

[tobyaxis]

Those two coatings are ok to use coolant. They will keep the edge of the tool sharp for a while longer than uncoated tooling. Coatings help chip evacuation too.

Coatings also allow for a higher temp range as well as higher RPMs and Feedrates, but not by that much.

[jl123]

Any one of them better suited for aluminum than the other?

[tobyaxis]

Any one of them better suited for aluminum than the other?

The TiCN i see the most in aluminum, but both are great coatings.

The TiALN (Titanium Aluminum Nitride) are better siute for exotic materials like Stainless, Inconel, Monel, Waspalloy, Haynes, and Hastalloy. Never Titanium for either of these tool coatings.

[kalmah]

DLC coating works very well with aluminium. You can machine without coolant aluminium with DLC coating . As example, Mitsubishi, OSG produce insert for dry machining of aluminium. In order to keep the sharp edge, the thickness is very low (0.3micrometers).
The disadvantage of this coating (lack of adhesion) is now resolved.

The advantage:
High hardness (>4000 HV)
Low friction coefficient 0.1

The disadvantage:

Maximal temperature : 500 °. It's not a problem when you machine aluminium. The temperature are always lower.
It's impossible to use this coating with steel, cast iron

[little bubba]

I tend to use TiCN on a wet application, and TiAlN on dry applications. I've heard but never verified that the Al in TiAlN coatings make them undesirable for use in milling aluminum, I've never had a problem running TiAlN wet in aluminum, though I don't get to play with aluminum much.

One thing that I have noticed and avoid like the plague is running a TiAlN coatings wet in steels. We had a long run job in A286 and TiAlN coated roughers consistantly gave 30% less tool life than the uncoated roughers, running wet. A little food for thought, I'm not sure why it happened, but it did.

[tobyaxis]

I tend to use TiCN on a wet application, and TiAlN on dry applications. I've heard but never verified that the Al in TiAlN coatings make them undesirable for use in milling aluminum, I've never had a problem running TiAlN wet in aluminum, though I don't get to play with aluminum much.

One thing that I have noticed and avoid like the plague is running a TiAlN coatings wet in steels. We had a long run job in A286 and TiAlN coated roughers consistantly gave 30% less tool life than the uncoated roughers, running wet. A little food for thought, I'm not sure why it happened, but it did.

Thermal Shock is why your tool broke down so fast. Plus some Cemical Factors played a roll. I don't know a lot about Cemicals but if you have ever made the mistake of mixing Amonia and Bleach, you get the picture.

[ctate2000]

TiALN is great when using HSS on aluminum. I use coolant with it and have no problems. The coolant seemed to help tool life. IMHO if you want the best bang for the buck use solid carbide uncoated for small tools .5 and less and coated HSS for the larger tools over .5. If you are moving large amounts of material and use large tools frequently then solid carbide is cost effective. I have found that small runs with light removal rates the coated HSS was a more cost effective choice for the large tools because of lower initial cost and becasue freqeuent handling makes them more suseptable to damage.

The alloy also makes a difference. If you are milling 6061, 7075 or similar alloys then coated HSS is a good choice. If you are milling die castings you need carbide or PCD to get any life.

[jl123]

My tooling is limited but lately I've scored some nice carbides off ebay. I bought 10 uncoated 1/4" EMs for $50 shipped from this company called attitude cutting tools I believe. They're now putting reserves on thier auctions now. Haven't tried them but they look really good but I'm just waiting on setting up a coolant system before giving them a run.

I wanted to try out some coated tooling so thats the reason for this thread.