Titanium Speeds and Warpage

[Aaron]

Does anyone have any experience milling Titanium plate? I am looking for info regarding Ti's tendancy to warp due to work hardening. Also suggestions for speed/feed rates and tooling- coated Carbide, CBN, or PCD? Do the values given in the Machinery's Handbook work well?

Thanks in advance.

 

-Aaron-

[Trevor Bailey]

I don't have too much experience with that material except for one occasion when I milled some putters out of it. I used regular speeds and feeds that I use for 304 ss and they worked fine. What ever you do, do not let the tool STOP while it is engaged in the material. It will work harden very fast.

[Jack Mitchell]

Aaron,

 

We typically view high speed steel cutters as the standard for shearing ability.

Carbide, in my estimation provides 50% shear and 50% deformation – true that this occurs at elevated rpm’s of about 4:1 in surface speed calculations.

 

A good analogy would be if you were to cut cheese with a hss cutter then it would be reasonable to expect a nice clean shear; arguably, the carbide inserts would not fare too well.

 

The place that I worked tried many approaches, we found that using hss end mills & slotdrill’s gave the best or most predictable results; treat this material as if it is mild steel for your feeds and speeds. (dwelling does not exist); (feed hold does not exist) else, try it out, learning the honest way is always your best teacher. – be prepared for the squeak and squeal of a slow rpm chew (once your into it, you will know exactly what I'm talking about).

 

Machinery’s handbook enters the realm of the extreme grey area when it comes to feed & speed recommendations. I would suggest the Machining Data Handbook for a very realistic starting point.

 

My experience is limited to about 60 hours on various aerospace components – you will find this experience an excellent learning opportunity (My experience with this material precluded the fantastic coatings that we all take for granted today).

 

One last note: keep a piece of this in your toolbox and do not tell anybody that you have it – I still only have one piece after twenty years; it’s so cool to show others how light the part is compared to other materials.

 

Please let us know what approach and result occurs.

 

Regards, Jack

[iowajim62]

Hi Aaron,

Have to ask a question before I give an answer.

What type of Titanium ?

6AL-4V,6AL-6V,or Commercially Pure Grade 2.

Depending on material type you can really push the tools, but like Jack said generally HSS is the way to go until you get down under .250 dia.

After that I only run carbide due to excessive flank wear which costs you in dull tools.

TICN coated baby endmills perform alot longer.

Drilling is ok down to .0469 with HSS in my jobs.

JM2C

[TheePres]

Iv'e cut to much of this material, but still havent figured it out. For roughing I use wavy style 6 flute ruffers, a knock-off of what International Tools sells, with 8% cobalt.

50 SFM .005-.008 IPR. If money is there, International does make a specific grade developed for Titanium, but quite costly.

Currently im working on a 50" x 50" titanium forging, to get past scale (alpha case) i use cheapest (from salvage yard) cutters because that shell will eat up anything anyhow.

Thinner areas do warp but more from inherent stresses than from work hardening.

 

[ 01-08-2003, 09:27 PM: Message edited by: TheePres ]

[Chris Rizzo]

For what it's worth, I've done some turning on 6al-4v, and found that SLOW speed and HIGH feed works well...speed kills (cutters). Also, I like to use coated inserts for roughing, and then switch to HSS with almost a burr/sharp edge for clean finish cuts with good surface finish.... just my 2 cents..

[Jack Mitchell]

One another note:

 

When deburring Titanium with a carbide burr mounted to a hand held die grinder, I destroyed my glass lens glasses; the very slight shower of yellow actually clinged to my glasses and pitted them – I was shocked that I actually destroyed my glasses in less than one hour.

 

Titanium is also what we call an extremely monitored substance – this stuff is lot sized, heat checked, magna fluxed, Xrayed, locked up, and documented to the nines – if you want a piece then you’re going to have to steal it (No kidding).

 

Most of the stuff that I machined was wing clips for Douglas and Boeing and some sort of forging used to catch the guide wires for a fighter jet when landing on an aircraft carrier –cool part but bitchy machining (real bitchy)!

 

We could not handle the parts with naked hands since our acidic nature would imprint and etch into the finish – cotton gloves only on finish machined parts; has anybody else had the same unusual experience?

 

Regards, Jack

[Chris Rizzo]

One comical story...

A material supplier I used to frequent delt in heavy plate material (mild ,s.s., aluminum, and titanium). They also do alot of plasma cutting (capacity to 14"!!). A particular job for plasma cutting a **** load of parts out of 1 1/2" mild steel (a36) plate. The operator ran the job with was he though was A36 plate...I'm not sure who finally caught it, but all hell broke loose when they discovered he had ran the job with a 1 1/2" plate of titanium!!!

[Finecut]

Here is another concern

Coolant.......... No clorinated coolants.

That goes for the water also. Chlorine is used in most water supplies to kill the bactiera.

This is a good rule to follow for all Ti.

The chlorine will react with the Titanium. You wont see it. But if your parts are ever heated or have special post process done they will fail

Ask who you are doing the job for about this.

They should tell you about this condition. Ive worked for Hughes Aircraft for some time.Thats when I Learned about this, and had to change out the coolant.

As far as feeds and speeds the previous post are correct. Always take a cut !!! No rubbing allowed with the tools. Min .01 for finish cut

treat it like 304.

And this stuff is not cheap but sure is neat

 

Finecut

[iowajim62]

Hi all,

Another thing is your hand wrenches, they can't touch the parts either. The chrome plating can contaminate the material just like the coolant.

And don't use black magic markers as this will bleed into the material as well. We machine the commercially pure stuff with regular coolant as there are no requirements by our customer for the contamination issue but every customer is different so be sure to check with them. And yes Jack you are right they got that stuff locked down so tight you would think it was Fort Knox.

[Jim Whipple]

Iscar 328 or Walters WMG 40 inserts have worked very well for me at about 140 sfm and .005 to .007 per tooth

I cut lots of 6alv4

I've had the same experience as Jack with bare fingers and black markers....Oops!

Never had any coolant issued though. At least not with OUR customers

HTH

Jim

[Aaron]

Wow!! Thanks for all the information. That definitely gives us more than a starting point. What we are cutting are wave solder pallets for silver soldering PCB components. Ti may be used over our standard material for thin wall section strength.

 

Thanks Again.

 

-Aaron-

[Ryeker]

We have machined lots of Ti in the Company I work for... Using solid carbide tools from a company called Severance. Their endmills & drills cut great... We did a lot of testing before running with these tools. they out performed the big guys like Sandvik, Kennametal & Valenite. The coolant we use is a full synthetic ( castrol 9954 ). Keep the tool moving and flood with coolant and it's a beautiful material to cut...! As mentioned in a previous post use speeds & feeds from SS

 

This is not a sales pitch, Just the facts...!

 

Good Luck...