[davereagan]

I doubled my tool life with Tialn coated endmills and facemill inserts when I shut the coolant off. It was hard to believe and I had to test it on a longer running job where I was chewing up inserts like PEZ candy cutting 316 stainless with a nasty plasma cut edge. I thought "well, maybe dry is better on mild steel but this stuff is running so hot, surely the tools would fry sooner without coolant". I shut it off and went from 5 parts per index to 9.

[Geof]

I doubled my tool life with Tialn coated endmills and facemill inserts when I shut the coolant off....

.....I thought "well, maybe dry is better on mild steel but this stuff is running so hot, surely the tools would fry sooner without coolant". I shut it off and went from 5 parts per index to 9.

5 to 9 is not doubling, don't exaggerrate.

I have found the biggest deterrent regarding running dry and fast is past experience; you just know it isn't going to work, but it does.

Also you have to get over the tendency to measure tool life in time. In miljnor's case changing to running dry may have halved the time to around three hours and it might have halved to tool life to 3 hours; but so what, the tool has done the job and you are three hours ahead.

I still fall into the trap of thinking in terms of running time for tool life rather than parts finished per tool per unit of time.

I think this quote is applicable;

"Habit is a cable; we weave a thread of it each day, and at last we cannot break it."
Horace Mann


But I don't know who Horace Mann is.

[Andre' B]

The way it was explained to me with ALTIN coatings was they need to get hot so the Al oxidises as it is exposed and the chip is then rubbing on an aluminum oxide surface. At cooler temps the only advantage you get from the aluminum is a little lubrication.

As far as tool life Geof, I agree that what matters is how many cubic inches/cm of metal gets turned to chips per dollar spent.

Same with cars and gas, its miles per dollar.

http://en.wikipedia.org/wiki/Horace_Mann

[tobyaxis]

well I wasn't in the mood to go HSM dry on it so i ended up with 320sfm at .0025per tooth with coolant and 1 cutter did the whole job which was about 6.5 hours of machining....so i must have been ok...usually they break long before that if you dont get into the sweet spot....IMO if i did HSM on H-13 all the time you could probably get great performance with Dry machining and get the machining time down to maybe 3 hours

Glad to hear things worked out Mike.

[miljnor]

well I haven't made punch tooling in years, but making this one made me remember all the stuff i had forgotten!

Of course i remembered it right after i was done and couldn't use it on this tool....but it works! Albeit not as good as it would have if I'd had a good memory that spanned like 13-14 years!

Truthfully i haven't ever made one this big before but all that old information would have been great anyway!

[Geof]

.... if I'd had a good memory that spanned like 13-14 years!....

13 to 14 years!!! Trivial; you wait for a few years when you find it is the past 13 to 14 minutes you cannot remember.

[tobyaxis]

13 to 14 years!!! Trivial; you wait for a few years when you find it is the past 13 to 14 minutes you cannot remember.

I'm not looking forward to this

[Geof]

I'm not looking forward to this

You should, the alternative is much less desirable.

[tobyaxis]

You should, the alternative is much less desirable.

What is the alternative to CRS, worm food??

[CarbideBob]

[QUOTE=Andre' B;612083]The way it was explained to me with ALTIN coatings was they need to get hot so the Al oxidises as it is exposed and the chip is then rubbing on an aluminum oxide surface. At cooler temps the only advantage you get from the aluminum is a little lubrication.
/QUOTE]

Very true,
As applied ALTin coatings are very soft and just this side of worthless.
You have to generate enough heat to "covert" the coating to AL2O3. One of the big disadvantages of "low temp" PVD coatings.

Many ALTin coatings also include a layer of TiCN to make them work at lower speeds as many users don't push them fast enough.
Bob

[Geof]

I went searching:

TiAlN coating
The TiN coating has now been superceded in many applications by the TiAlN coating. The colour is of the TiAlN coating is dependent on the Ti:Al ratio within the coating and can range from black to bronze. TiAlN offers superior performance for a range of metal machining and fabrication applications. The reason for this lies in the addition of aluminium to TiN or specifically the formation of aluminium oxide on the surface of the tool which increases the operational temperature range of the coating to 800 deg.C compared with 500 deg C for TiN. As the TiAlN coating is heated in air a thin layer of amorphous aluminium oxide forms on the surface of the coating, which protects the coating from further oxidation. This results in better hot hardness than most other coatings. In many high speed turning operations TiAlN outperforms TiN or TiCN because of the protective oxide layer. This has recently been increased by the addition of chromium and yttrium or vanadium to the coating increasing the temperature range to beyond 900 deg.C. The TiAIN coating is also tough resulting in a reduction in coating chipping...

The 'pushing hard enough' is a bit of a trick. I have demonstrated to myself that it is possible to push too hard if the cutter is deeply buried and never gets a chance to lose a bit of heat in the air blast; the cutting edge just abrades away. Mind you everything was incandescent by this point.

I still find it difficult to believe that this coating works like it does, I know it works but all my experience cringes when I push the green button.

[miljnor]

Yes and the initial entry with the sparks always makes me tense up..but they go away as the tool clears the entry cut.....dry cutting is scary when you first get into it!

pushing the envelope is fun as long as you dont waste too much money doing it!

[Geof]

......pushing the envelope is fun as long as you dont waste too much money doing it!

As it turns out I don't think I have 'wasted' any money, all the time I spent playing has been recouped in several jobs since then.

I even wrote code to open up holes 'trochoidially' starting from drilled hole and then spiralling out using semicircles. Took about twenty minutes of punching in coordinates, works like a charm and I can do different size holes with the same set of coordinates just by using combinations of different size tools and 'faking' the tool diameter.

[miljnor]

that's right! my motto: Adapt, Improvise and Overcome! (the knights of the round table)

[UWP_Wes]

I would be inclined to think that the slots shown in the video would be better done by plunge milling.....

I wonder what the difference in cycle time would be for trochoidal vs. plunge milling? Plunge milling would also avoid the machine wear some members pointed out.

[Geof]

I would be inclined to think that the slots shown in the video would be better done by plunge milling.....

I wonder what the difference in cycle time would be for trochoidal vs. plunge milling? Plunge milling would also avoid the machine wear some members pointed out.

What do you mean by plunge milling?

I am dubious that any method could beat the pseudo-trochoidal method I used. Since posting those videos I have discussed the programming with someone very competent in Mastercam. They produced a Mastercam program that did the same operation in something like half the time. This prompted me to rewrite my program removing some wasted moves and the net result was my time came down to around 25 seconds per slot from 40 seconds.

If you provide some code I will run it on my machine.

[John Holmes]

Does the new version of Mastercam have a plunge milling cycle?

[UWP_Wes]

I do not know if MasterCAM has plunge milling; I assume it does. I know Catia and OneCNC have it (even BobCAD has plunge milling now). You do not really need CAM software to do plunge milling, as in your case it would just be a simple drill cycle. CAM software is needed to do plunge roughing on 3D contours (e.g. for rouging deep injection molding tools).

The theory is that you can remove material more rapidly by plunging in Z than by doing Z level rouging. Of course this is application and material dependent.

Here is a video of plunge roughing.

[ame="http://www.youtube.com/watch?v=OBvf2Vv7wl4"]YouTube - Kennametal Z-Axis Plunge Milling Cutter is the Smart Solution for your Milling Needs[/ame]

[Geof]

Does the new version of Mastercam have a plunge milling cycle?

I don't have the faintest idea; as I asked above what is plunge milling?

EDIT

Question was being answered while I was asking, thank you.

[Geof]

Having looked at the video I am still dubious.

The slots were only 3/4" wide which more or less rules out an insert cutter and I know that an endmill cannot be plunged as fast as it can cut sideways.

It would not be a simple drill cycle because the cutter moves slightly away from the cut as it retracts upwards.