[gaser25]

Just replaced my fadal vmc40 which is for sale with a 1997 haas vf4. I would like to machine some titanium parts. I hear its a bit tricky. Any input would be appreciated.

[DSL PWR]

Be carefull, as titanium chips are very flamable, and putting water on them dosn't put the fire out.

[grinderdust]

I could be way off here but I think magnesium is the metal with the flammable chips. Titanium, I believe is stable under normal contitions. Please do your research. I would hate to be responsible for someone getting hurt. I did some machining of titanium maybe 15 years ago with no problem. On the lathe I had no problems other than stringy tough chips. On the mill you have to use proper speeds and feeds and sharp, high quality cutters to get good results. Also a good sturdy machine tool and rigid setup are essential. I guess that last part is pretty obvious.

[rapidtraverse]

It cuts like Al. at the right surface feed. Try 35.

[dertsap]

treat it like you would stainless
keep in mind if it work hardens then your going to have some fancy cutting to do , insert mills and carbide endmills would be a smart bet .
If your drilling , it may be a good idea to look at carb drills as well , you can take a heavier cut and there would be less chance of work hardening , if an hss drill dulls while cutting youll be in trouble

[SWPM]

I have been cutting alot of titanium lately and found that using a light radial cut (.030"-.040") with the deepest depth of cut possible on the part(within reason no more than 2.0"). I use coated high helix carbide e/ms and the tools will last alot longer using a chip load around .015" per flute and a surface footage of around 175 ror roughing and down to .010 per flute for finihsing. I know this sounds kind of out there but ive had alot of luck so far with this.
The most important thing is quality tools.

[mxtras]

Titanium does burn. Make absolutely certain that you have a D type extinguisher handy - one for flammable metals. I don't think an ABC will do anything should you light up titanium.

The above comments are accurate. It machines very much like aluminum - at least the alloys I am familiar with do.

Scott

[dpuch]

A quick google turned up http://www.titanium.com/titanium/tech_manual/tech16.cfm which has the fire information.

It would be better if you got the information from your supplier for the alloy your using though.

Dale

[bookwurm99]

Titanium does burn. Make absolutely certain that you have a K type extinguisher handy

i believe the right extinguisher is a D type not K. K is for combustible cooking.

bookwurm99

edit:sp

[ConKbot of Doom]

Titanium does burn. Make absolutely certain that you have a K type extinguisher handy - one for flamable metals. I don't think an ABC will do anything should you light up titanium.

The above comments are accurate. It machines very much like aluminum - at least the common alloys do.

Scott

D class extinguishers are for metals, K class are for grease fires.

Definitely either use a D-class or dont use one at all. Water, CO2, and in some cases, even sand can make magnesium fires worse, not 100% sure, but I dont see why metal fires would be so different.

[davereagan]

I can't believe you guys are saying Titanium machines like aluminum. Are you talking about commercially pure titanium? There is a world of difference between that (40,000 psi tensile strength) and 6AL-4V. Here's a hint: 4% vanadium means it has more vanadium than a premium tap. 125 sfm for face milling is moving right along. I have machined it until the inserts dulled and I was making sparks. I have no knowledge that it burns. Magnesium is knwon for burning and putting it out is quite difficult and counter intuitive. I've heard of a new "triple five" alloy that is even harder to machine than the standard 6-4 alloy. If you quote this at 5 times higher than making the same part in mild steel, you are badly underestimating it. It is one humbling material. I went through TiALN coated inserts like they were PEZ candy. The guy who mentioned profile milling knows what he's talking about.

Dave

[dertsap]

flamability of titanium shouldn t be a problem
i ran parts before that we run a 5/8 -11 tap ,normally most of the order was ss and some were titanium , we used the same prog but we had to slow down the speeds and feeds for the titanium parts,on one particular order i forgot to slow the 5/8 tap speed from 550 rpm to 400 ,the tap was glowing orange when it came out of the part and it lit the cutting oil in flames ,air nozzle save my butt , no titanium set fire and there was a lot of chip in that machine ,

the threaded hole was so hard it was near impossible to deburr , noone will ever strip that baby

[dpuch]

Please! read your material data sheets.

While fire may not be likely in most normal situations, it IS a possability. Be prepared.

III. FIRE & EXPLOSION HAZARD DATA

FLASH POINT (F): N/A
FLAMMABILITYLIMITS (%/VOL): LEL: N/A


METHOD USED: N/A
UEL: N/A

AUTO-IGNITION TEMPERATURE (F): 2200F for metal in air, 480F for powder in air.

EXTINGUISHING MEDIA: Dry table salt or Type D fire extinguisher.

SPECIAL FIRE-FIGHTING INSTRUCTIONS: Remove uninvolved material; allow fire to burn out. Fire can be controlled by covering with dry salt or powder from Type D fire extinguisher. Carbon dioxide is not effective.

UNUSUAL FIRE AND EXPLOSION HAZARDS: Dry titanium burns slowly while releasing much heat. Water applied to burning titanium may cause an explosion. Piled chips may burn vigorously.

Powder isn't that likely from milling, but that temp isn't that high either.


For milling, try some of these links with suggested speeds and feeds, as well as milling practices.

http://www.mmsonline.com/articles/010402.html
http://www.niagaracutter.com/solidca...speedfeed.html
http://findarticles.com/p/articles/m...6/ai_112862178
http://www.timet.com/fab-p17.htm

[davereagan]

I once ran my facemill inserts so dull on some Titanium 6-4 alloy that I shut the lights off and could see fire coming off the cutter. No flames. vYou guys have tihs confused with magnesium which can burn down a machine if it gets going.

Dave

[Pressfit]

Yes indeed Ti will also burn and cause a fire in and around a machine. I saw it personally happen with another Machinist over 25 years ago on a 50 inch King VTL. The part was a jet-engine exhaust duct about 4 feet in diameter which he was spinning around 20 or 30 rpm and cutting dry. WAY, WAY too much sfm and the chips came off red and fell down into the chip pan which probably had some residual oil or other matter in it.

Next thing you know there was smoke billowing around the machine and we had to evacuate the shop so the company fire department could put it out. After we were allowed to go back to work the machine was scorched with black soot and the entire wiring system was burnt out. The company had to send the machine out for a re-build.

Whenever we had to grind Ti, the grinder had to be completely cleaned of any dust and completely de-greased and wiped down. Then inspected and okayed by the fire department before starting.


Note the heading (Precautions) towards the bottom of the page....
http://en.wikipedia.org/wiki/Titanium

[davereagan]

Good info. I still think the above posters had it confused with magnesium. It sounds like the oil burned after the white hot titanium ignited it. Maybe they burned together.

[mxtras]

No - I am not confused. I have lit up a chip tray on a lathe. I was turning an ultrasonic grade of Titanium and that particular alloy will burn, I assure you. It will not actually flame - it burns the way steel wool burns except it is white hot and extremely bright. It's hot enough to catch adjacent combustibles on fire, and that is the hazard.

I was off on the type used to extinguish - it is type D, not K as I mentioned in post #7. Sorry. I guess I had fried chicken on my mind!

Scott

[davereagan]

OK, you win. Magnesium is still far more flammable, agreed? That's what they make fireworks from. I've seen carcass CNC machines for sale. Iron still there, wiring all burned out. Magnesium is always the culprit. Water seems to make it worse.

[Gumby]

The fire aboard the USS Enterprise in ’69 was compounded by the burning aircraft that was struck with a zuni rocket and eventually lead to the detonation of several large (500lb) ordnance on that aircraft after a failed attempt to extinguish the fire was made by a single Chief who was equipped with the wrong type of extinguisher. Those aircraft frames are made out of titanium and pose a significant fire fighting problem when you are not equipped with the proper tools.

Titanium can burn from normal machining operations if care is not taken to limit feed rates and cool the work piece.

This article outlines the difficulty in machining titanium alloys.

Just an FYI you can use graphite powder in place of a Type-D extinguisher if you can not afford the extinguisher. If you have to use water to combat a class D fire make sure you do not direct a solid beam of water at the fire as this will most likely result in a steam explosion. You can however use a mist spray to fight the fire with little risk of an explosion.

I hope this helps,
~Gumby