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Dean jeffery
07-11-2014, 03:34 PM
Need to machine a double D in some Ti, the best way would be broaching but to expensive for the tool.
The size would be 8mm across flats and 12mm rads oval like, would this be possible would need to go 20mm deep.

Cheers

EddyCurrent
07-11-2014, 04:56 PM
I don't know but I read this somewhere else from someone who cuts Titanium;

cobalt endmills give the best service.
paraffin is the best lubricant.
heat build up is a major factor.
use a slow spindle speed but higher feed rate.
you need a strong machine
climb cutting works well

Dean jeffery
07-11-2014, 04:58 PM
OK cheers.

m_c
07-11-2014, 05:19 PM
Is this external or internal?
Also through or blind?
.
Going by the mention of a broach, I'm guessing internal, in which case you're going to have to either rely on rounded or overcut corners. However without more details, it's just speculation.

Dean jeffery
07-11-2014, 06:29 PM
Internal was guessing rounded corners, but ideally with out.
Not sure what the smallest ended end mill would be but any smaller than 4mm this would prob not be possible.
What would be the smallest end mill poss, or max over cut corners.

Cheers

m_c
07-11-2014, 06:44 PM
You can get sub mm micro endmills, but none that would manage to go 20mm deep.
Having had a quick look at a catalogue, the smallest diameter that will go 20mm deep is 4mm, so you'd be looking at a 2mm radius on every corner, although you may need to increase that to avoid chatter in the corners.
.
Do you really need to use a double D?

Dean jeffery
07-11-2014, 07:27 PM
Cheers dint think it would be possible to mill it, 2mm it would no fit. So would need under cutting, although this is not a problem regards affecting the function because their would be plenty of flat left for drive. But just looks unprofessional, and looks play a part.
Has to be a double D the drive is a double and can't be changed, so this has to be the same.

Cheers

m_c
08-11-2014, 12:41 AM
The other possible option is an EDM sinker, but it all depends on how much you want to spend.

Dean jeffery
08-11-2014, 07:02 AM
EDM I would have thought be more expensive than standard broaching, I may go the route of drilling out the corners shouldn't look all that bad.

Cheers

Robin Hewitt
08-11-2014, 10:07 AM
I suspect this is just a ploy to make me Google for "double D" then have to explain to my wife why I am targeted with lingerie adverts for the foreseeable future :joker:

Am I the only one who doesn't know? What is a double D?

Dean jeffery
08-11-2014, 10:25 AM
It's a boob size lol
http://tapatalk.imageshack.com/v2/14/11/08/4f65dbc08aef6629de76917c8956c471.jpg

To go through something sim to this

http://tapatalk.imageshack.com/v2/14/11/08/aba8ddd8cf73b4835e56068dd64ac03c.jpg

deisel
08-11-2014, 11:58 AM
Am I the only one who doesn't know? What is a double D?
No:applouse:

m_c
08-11-2014, 09:05 PM
EDM would be expensive if you were paying someone else to do it, however if you've got time and are willing to build a machine, then it wouldn't be quite so bad, but it depends on what your goals are.
Another option could be to machine the shape as near as possible on a mill, then use a small shaper and custom cutter to cut the sharp corners.
.
Dealing with Ti isn't that much different from stainless. You've got to use sharp tools and ensure they never rub as it'll workharden in the blink of an eye. It also produces swarf with a far shaper edge than stainless, so you have to be careful handling it.

EddyCurrent
08-11-2014, 09:54 PM
Am I the only one who doesn't know? What is a double D?

No once again, the first thing it reminded me of was Double Diamond ale :beer: I could sup a few of those at one time.

Dean jeffery
08-11-2014, 11:45 PM
EDM would be expensive if you were paying someone else to do it, however if you've got time and are willing to build a machine, then it wouldn't be quite so bad, but it depends on what your goals are.
Another option could be to machine the shape as near as possible on a mill, then use a small shaper and custom cutter to cut the sharp corners.
.
Dealing with Ti isn't that much different from stainless. You've got to use sharp tools and ensure they never rub as it'll workharden in the blink of an eye. It also produces swarf with a far shaper edge than stainless, so you have to be careful handling it.

Cheers for the info but EDM is out of my league, think I will drill the corners and see how it looks. This is the easiest option I think, failing that machine to has close has pos like you say and then shunt be to hard to make a broach just to take the corners out, should be able to use a small press then.
Failing both these options I would have see about getting them done else where, just wanted to make these with paying anybody to do any machine work.

Cheers

magicniner
09-11-2014, 02:38 AM
Mill as close as you can then finish with a custom made profile tool in a shaper, press or even using a mill quill action with the rotation locked.

Dean jeffery
09-11-2014, 09:17 AM
Yep that's what I was and advised and thought about, maybe just easier and quicker to have them broach. Thinking about it it may cause issues using a 4mm end mill to cut titanium, maybe just easier to drill 8mm or so and then just send to be done. Just depends on the cost for doing 100 at a time, will see how the over cut looks first but then still left with the dilemma of the 4mm cutter. Alloy would be no probs and some would be done in alloy, cheers for all your inputs.

mekanik
09-11-2014, 10:45 AM
Hi Dean
It might be possible to use a wobble/rotary broach to do this but the only type i have seen leave a symetrical hole ie hexagon internal spline ect but the holders l can be self made but you would have to get the tool made as the the usual silver steel tool(hobyist aproach) would probably not fair to well with Titanium.
Just a thought but if you are running batches of 100 you need to get tooled up and a wobble broach setup can be done in the lathe or mill.
Regards
Mike

Dean jeffery
09-11-2014, 10:50 AM
Hi Dean
It might be possible to use a wobble/rotary broach to do this but the only type i have seen leave a symetrical hole ie hexagon internal spline ect but the holders l can be self made but you would have to get the tool made as the the usual silver steel tool(hobyist aproach) would probably not fair to well with Titanium.
Just a thought but if you are running batches of 100 you need to get tooled up and a wobble broach setup can be done in the lathe or mill.
Regards
Mike

Cheers Mike I have seen this been done just but not seen or found any double D's clearly can be made to order, also not sure on what depth these allow. But is another option to consider and has you say if tooled up then this would make is post in doing it all myself and all on the mill.

Cheers

Clive S
09-11-2014, 10:58 AM
Very interesting https://www.youtube.com/watch?v=gUEcagEmmZo and http://www.polygonsolutions.com/rotary-broaches/special-form-rotary-broaches/double-d-rotary-broach/You learn something new every day:thumsup: ..Clive

Dean jeffery
09-11-2014, 11:05 AM
Seems they call the Double D a spur, makes sense because that's what I plan on making.
Seen some tube vids before but not that 1, ones I've seen have normally been slow.
Cheers