Author Topic: Milling Titanium  (Read 18675 times)

Offline doubleboost

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Re: Milling Titanium
« Reply #25 on: June 18, 2011, 01:31:09 PM »
Dave
Had a word with the lads who machine the titanium.
They were using "grade 3 " a 5mill cutter running at 5000 rpm with coolant flood
They reckon if you let the job get hot it goes very hard , the finish they are getting is very good
John

Offline jim

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Re: Milling Titanium
« Reply #26 on: June 18, 2011, 01:36:56 PM »
Jim,

Thanks,
If I may - what tools do you use HSS /  Carbide

With respect to steel do you use a faster or slower spindle speed?

 :beer:
DaveH

Either will work, but slow and steady, at least half the speed of steel and a slow feed to. as soon as the tool starts to wear, it'll need changing/regrinding.

HSS will cut very well (it will on most materials if its sharp), in fact, unless you've got the power to take a good size cut, throw away tipped cutters are a waste of time.
a bit like lowered suspension on little cars, done for form, not function!!!
if i'd thought it through, i'd have never tried it

Offline DaveH

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Re: Milling Titanium
« Reply #27 on: June 18, 2011, 02:20:17 PM »
John, Jim,

Thanks very much for the info. :thumbup:

Haven’t tried anything yet but I have much better idea when I do. :)

Thanks
DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline mgj

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Re: Milling Titanium
« Reply #28 on: June 18, 2011, 04:13:38 PM »
I don't know what this is for but  basically there is no such thing as a bad finish on Ti. Because of its notch sensitivity and hence a very nasty habit of propagating cracks from any surface imperfections, the finish is either good, or it goes in the trash can. (Not if one is making a gear for a clock or something, of course, but where it is stressed to a useful load to take real advantage of its properties, like say suspension arms or con-rods)

Obviously there are many ways of machining Ti, all of which are succesful - probably the secret is simply a sharp tool. Still I'm surprised, with a work hardening material, that there is advice to keep feed rates down.

Offline jim

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Re: Milling Titanium
« Reply #29 on: June 18, 2011, 04:24:12 PM »
i've been machining it for 16 years
if i'd thought it through, i'd have never tried it

Offline doubleboost

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Re: Milling Titanium
« Reply #30 on: June 19, 2011, 08:17:16 AM »
Hi
Found the pictures of that titanium con rod
As usuall the pictures dont do it justice



John

Offline DaveH

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Re: Milling Titanium
« Reply #31 on: June 19, 2011, 08:38:53 AM »
John,

My word that is good, especially because it is made from titanium, small as well. :bugeye: :thumbup:

I'm really going to get my butt in to gear and have another go.

Thanks for that :clap:

DaveH

(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline DaveH

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Re: Milling Titanium
« Reply #32 on: June 19, 2011, 08:44:38 AM »
Jim,
i've been machining it for 16 years

So Jim when you coming to South Africa then? :D :D :D

 :beer:

DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline Kinkajou

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Re: Milling Titanium
« Reply #33 on: July 28, 2011, 10:05:02 PM »
I am a Vet and have to perform orthopedic surgery regularly.
Usually we can adapt implants made for people and use them on animals. But  we sometimes have to provide special solutions with patients and make impants made out of Stainless steel  or Titanium 6Al4V Eli.

This are some pictures of the first wrist replacement made for a dog.
Machining titanium has a lot of little problems as we found out. It will self ignite sometimes and that is scary.
Turning was best done at high speed and drilling as slow as posible. In both cases using a lot of cutting fluid.
We like to use carbide tools , very sharp. Steady, and progresive cuts, with little load.

This one was one of our favorite patients. Called Kissy, had arthritis that deformed very much the limbs. ( antebraquiocarpal joint affected seriously)


I started by evaluating the patient, then designed the implant using Vector Works in a Mac and finally machined the individual parts using a little lathe mill drill from grizzly ( I use this for my hobbies and a little for my work) . Implant looks like a fork / hinge.

There is a radial component and a metacarpal component. Carpal bones were almost all removed.


This is the Xrays showing the implant in place.


Titanium is a very interesting metal to work with. It is like aluminum sometimes, but it can harden in a snap and break the tools very easy.
It is a lot better than Stainless steel when used for implants, because it is very biocompatible.


Offline DaveH

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Re: Milling Titanium
« Reply #34 on: July 29, 2011, 03:53:16 AM »
Kinkajou,

Wow that's impressive.

DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline Henning

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Re: Milling Titanium
« Reply #35 on: August 02, 2011, 08:05:15 AM »
Kinkajou,

Wow that's impressive.

DaveH

I will second that!

GREAT post and work!
Henning

Just because i can't, doesn't mean i shouldn't?
Tool- lover, with a collection to show for it!

Offline AdeV

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Re: Milling Titanium
« Reply #36 on: August 02, 2011, 12:21:56 PM »
Kinkajou, let me get this straight, you made a TERMINATOR hand and implanted it in a dog?!?   :bugeye:

:lol:

Even so, really good work, it looks amazing.
Cheers!
Ade.
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Location: Wallasey, Merseyside. A long way from anywhere.
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