Suggestions for milling Titanium

[nickbe10]

On 10/30/2023 at 12:37 PM, MrFish said:

Try running a 13 tooth endmill in Ti6al4V on a HAAS !!!

Or anything but a pretty open OUTSIDE profile on any machine.

[Kyle F]

On 10/30/2023 at 2:37 PM, MrFish said:

From my experience this is very much machine and setup specific. You'll need both a rigid machine and setup for that.Try running a 13 tooth endmill in Ti6al4V on a HAAS !!!

Wouldn't it be easier on the machine than running a 4 flute though? I mill 718 inconel on a wimpy ol' haas and going from 4flute to 8flute endmills was a game changer 

[Metals and materials]

On 11/2/2023 at 1:41 PM, Matthew Hajicek - Singularity said:

Go for it.  Just make sure the drilled diameter is what the tap manufacturer recommends.

Okay, perfect. THank you very much!!

[MrFish]

On 11/4/2023 at 7:33 AM, Kyle F said:

Wouldn't it be easier on the machine than running a 4 flute though? I mill 718 inconel on a wimpy ol' haas and going from 4flute to 8flute endmills was a game changer 

Generally not as you have more flutes engaged at any one time so more load on the machine. Big rigid machines can handle this but not so much on the lighter duty ones.

[Aaron Eberhard]

15 hours ago, MrFish said:

Generally not as you have more flutes engaged at any one time so more load on the machine. Big rigid machines can handle this but not so much on the lighter duty ones.

Good call.

I just did the calcs (well, by that I mean I plugged it into Eldar's program, cause ain't nobody got time to calculate things manually!)...  Using all the recommended settings (stepover/DOC/etc. with a .5 endmill) for 6Al.

4FL is 14.7% Stepover (.0737"), .00286FPT/282SFM (24.7IPM/2156RPM) = 310.5lbs of cutting force on the tool.  1.6 cubic inches per minute removed.

8FL is 8.4% Stepover (.0422"), .00365FPT/360SFM (80.35IPM/2750RPM) = 453.3lbs of cutting force on the tool.   3.0 cubic inches per minute removed. 

Just for an additional calculation, when I changed the 8FL down to the 4FL material removal rate (74% of recommended feeds and speeds), the cutting force was still higher @ 335.5 lbs of force... But the tool life % was at 254%

On 11/3/2023 at 2:33 PM, Kyle F said:

Wouldn't it be easier on the machine than running a 4 flute though? I mill 718 inconel on a wimpy ol' haas and going from 4flute to 8flute endmills was a game changer 

Based on the above, I wonder if the harmonics/consistent loading was better in Inconel than than the actual change in force on your haas?

[Kyle F]

6 minutes ago, Aaron Eberhard said:

Based on the above, I wonder if the harmonics/consistent loading was better in Inconel than than the actual change in force on your haas?

really interesting info you posted on those cutting forces in relation to flute count,.. it all makes perfect sense when I really think about it, but my knee-jerk intuition was telling me the exact opposite lol! 

It must have just been a cocktail of variables that led to better machinability with the 8flute on my wet cardboard box of a haas. I certainly wasn't using a straight 1:1 change on speeds/feeds/ipt when I swapped from 4flute to 8flute as well. Thanks again for that info!!

[Jake L]

30 minutes ago, Kyle F said:

my wet cardboard box of a haas

LOL 

[crazy^millman]

Another part of the conversation is holders and setup. ER-32 holders and Aluminum fixture plates like some customers do and it can be the best machine in the world, but junk in and expect junk out. 

[Jobnt]

In regard to the above references to tapping, I agree form taps are a PITA and threadmilling is the safest (albeit slowest) option.

BUT... The standard tap-drill charts don't apply to hard metals like titanium.

In the Bible it says when tapping hard metals you can deviate from the standard 70%-75% engagement and go as low as 55%. This makes tapping Ti almost like tapping alum with a cut tap and the correct fluid (Big 'ol PLUS ONE to using Molly D). So unless the drawing specs what max size hole to drill (I really HATE those kinds of engine ears) you should use the Bible and save yourself some headache.

 

On 11/6/2023 at 8:34 AM, Kyle F said:

wet cardboard box of a haas

^^^ True story!!  

[Jake L]

6 minutes ago, Jobnt said:

In the Bible it says when tapping hard metals you can deviate from the standard 70%-75% engagement and go as low as 55%. This makes tapping Ti almost like tapping alum

Is that before or after Jesus turns water to wine? 

Genuinely curious about this, where are you getting this 55% rule from?

[Jobnt]

10 minutes ago, Jake L said:

Is that before or after Jesus turns water to wine? 

Genuinely curious about this, where are you getting this 55% rule from?

It's vodka.

The Machinists' Handbook. Under Threading / Hole Sizes I believe (it's been a while). It discusses the thread strength of harder materials and how smaller thread engagement reduces torque requirements and broken taps while providing the same thread strength as softer metals with higher engagements. 

I don't have a copy of the Bible any more but I'm sure someone else here has seen this. 

[AHarrison1]

10 minutes ago, Jake L said:

Is that before or after Jesus turns water to wine? 

Genuinely curious about this, where are you getting this 55% rule from?

There a few different charts that show what sort of engagement is needed for material types,

here is one eg https://littlemachineshop.com/reference/tapdrill.php

[Jake L]

19 minutes ago, Jobnt said:

It's vodka.

The Machinists' Handbook. Under Threading / Hole Sizes I believe (it's been a while). It discusses the thread strength of harder materials and how smaller thread engagement reduces torque requirements and broken taps while providing the same thread strength as softer metals with higher engagements. 

I don't have a copy of the Bible any more but I'm sure someone else here has seen this. 

Machinery's Handbook Link

17 minutes ago, AHarrison1 said:

There a few different charts that show what sort of engagement is needed for material types,

here is one eg https://littlemachineshop.com/reference/tapdrill.php

Learn something new everyday, thank you both