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View Full Version : Machining 6AL-4V titanium



lathehand
03-15-2007, 09:54 AM
Got some on the way and need to do some milling, turning, drilling , and boring. How does titanium machine?

garyphansen
03-15-2007, 09:59 AM
You need carbide, I have had no luck with HSS even though some clame to have had. Gary P. Hansen

Swarf&Sparks
03-15-2007, 10:03 AM
Carbide, nope. Only time I turned Ti, was using ceramic.
Needed masonry wheels on the angle grinder to cut lengths.

I've ordered the tool holder and a couple of spare inserts from Sherline. If they get their finger out, I will report to this board.

Lovely to TIG weld tho.

sch
03-15-2007, 10:52 AM
Apparently work hardening is a problem with 6Al4V alloys, carbide will
work IF you take this into account. Ceramic doesn't much care either
way. Bunch of articles on the web about machining this alloy but
they assume your machines weigh over 3tons and have at least 7.5hp.

SGW
03-15-2007, 11:06 AM
There have been discussions of machining titanium in the past, so a search of the archives should turn up something.

The little I've done with titanium (unknown alloy) suggests that wicked sharp HSS works pretty well -- though your mileage may vary.

What is almost certain to be true, regardless of the alloy, is that machining titanium generates an astounding amount of heat, so coolant may be advisable. Apparently there is the danger of it catching on fire, so coolant may be advisable for that reason, too.

Rusty Marlin
03-15-2007, 11:30 AM
In a shop I was at in NH we cut Ti almost exclusively. We never used carbide because it isn't sharp enough. HSS and Cobalt tooling at low RPM, you can just make out the individual flutes on a 1" 4 flute tool. Too fast to count but they are visable as individual flutes. Very high volumes of water soluble coolant and heavy feed per tooth, .008-.012. and a 25-100% DOC on the tool. You have to cut Ti, if you nibble at it will work harden and then you are well and truly screwed. If your machine can handle climb milling, DO IT.

LES A W HARRIS
03-15-2007, 01:02 PM
Got some on the way and need to do some milling, turning, drilling , and boring. How does titanium machine?

Sharp COBALT Tools, start at 35 feet per minute, may have to go to 20 fpm, MINIMUM CHIP .002", .004" might be better, Need to hold part secure, flimsy setup are pre-doomed, Basically keep cutting do not dwell, Keep Cool, Bags of coolant. Plate material will move around, May have to Ruf machine, then finish. Grinding, done a bunch, slow wheel 1200 - 1500 ft/min, Black crystalon abrasive, Norton was the best, 37c60jvk? Brain cells failing, Use It or lose It. Observe and understand whats happening.
May sucess be with you.

lathehand
03-15-2007, 02:27 PM
Thanks all, looks like I got some fun ahead. I didn't think it was as bad as it sounds. Well, forewarned is forarmed. Luckily there are no tight tolerances for the project parts. Also it is kind of a joke to make these motorcycle parts out of titanium for weight savings. Drive around the block one time and the gas burned would weigh more than the differance in weight between the aluminum piece and the titanium one.

greatbot
03-16-2007, 04:05 PM
I've been machining titanium on a SB 16" with a QCTP and carbide without much trouble; great finish! Be careful, the turnings do burn! Made a basketball sized pile for 4th of July and lit it (butane grill starter); it burns HOT and white (unlike magnesium which has a bluish tint).
Be careful on the lathe as titanium conducts heat very poorly and as such the cutting area heats up fast. The chips don't turn color like steel so you don't get as much of an indication that things are getting hot. I was cutting off a 2" diameter bar and was about 2/3 thru when I noticed a little white spark at the cutting edge and then the swarf hanging from the cutter was burning. It dropped into the chip pan (where all the earlier Ti turnings were) and then they all started to burn; they were hot and cutting oil covered; I grabbed a piece of wood and scraped them all onto the cement floor. Bit of a scare! The problem is the intense heat that is generated.
Police your Ti turnings and don't let them accumulate.

Pete

john hobdeclipe
03-16-2007, 10:27 PM
I've been "playing" with some titanium lately, nothing really precise. I've found, like the others here, that your cutting tools need to be really sharp. I've not had any trouble parting off small 1/4" to 3/8 inch diameter pieces with a HSS tool. Likewise, it mills OK with HSS endmills, but they must be sharp.

We've discussed the titanium & magnesium fire hazard thing recently in another thread a month or so ago. Just for the fun of it, I took a little handful of Ti swarf, put it in the middle of the concrete floor, and put a match to it. Hooeee, wish I had put on some welding glasses. It's just like looking at a flashbulb. (Sorry, some of you young whippersnappers probably don't know what a flashbulb is.)

ckelloug
03-17-2007, 01:36 AM
When you talk about flashbulbs, have you seen one of these:
http://www.flashbulbs.com/meggaflash/meggaflash.html

I got technical samples of these from EG&G before they were spun off into meggaflash when I was in highschool. They're the size of hundred watt lightbulbs and will rock your world when they go off. I suppose they're not so impressive to a guy who started on gas lamps:D

john hobdeclipe
03-17-2007, 09:15 PM
I suppose they're not so impressive to a guy who started on gas lamps:D
Whale Oil Lamps, son, Whale Oil Lamps.

Those flash lamps look like they would be rather impressive. Are they single use, like the magnesium filled flashbulbs I was referring to, or are they semi permanent like a strobe?

It's been so long since I've used guide numbers that the figures don't mean anything to me any more.

Swarf&Sparks
03-18-2007, 01:14 AM
Now why couldn't I find those while I still had the Speed-Graphic?

john hobdeclipe
03-18-2007, 02:38 PM
Now this would be an interesting little weekend project: A working replica Speed Graphic CNC'd from BILLET titanium.

Swarf&Sparks
03-18-2007, 03:11 PM
So you're gonna build a speed-graphic with a titanium focal-plane shutter John? :eek: