Inconel 725 Nace

[Matt Boozer from L&R PT]

We just starting machining this stuff and one thing I am noticing is that when drilling the web of the drill chips out really bad. The lead edge looks decent. I can only assume that it is from the drill not dwelling in the bottom of the peck. We ( myself and our rep )tried getting mastercam to post the code out long hand with a dwell and nothing but trouble.

 

we were able to get it to post with a dwell long hand but it seemed to not want to pick up our peck That is were we threw in the towel.

 

I can type the code up the way it need to be, just trying to stream line the process for other guys in our shop.

 

We have tried Morse cobalt drill, precison twist, and others but it seems to be the same story just might get more tool life out of others.

 

Andbody have any Ideas or suggestions??? Thanks in advance

[Superman]

Don't let it dwell,

or peck ( it should chip-break itself )

 

Dwelling and pecking adds to the work-hardening of this xxxx material, once that happens, any following tools will cut like crap

...mever, ever let your tool stand still on the surface

 

The trick is to make the tools work harder, you only get X number of minutes tool-life, what material you can get out in that time is up to you

 

Inconel 718 has 18% machinability ( at least it has a little iron in it), try doing In100 ( 9% machinability ), and it has 0% iron

[Matt Boozer from L&R PT]

Ok, the no peck and dwell I agree will, I have a few question since you seem to have machined this stuff.

 

What type of drills are you using? When you give your drill type can you please give some surface feet recommendations.

Are you using High pressure coolant?

We are drill approx. 3 inches deep

 

The machine I am using has standard thru the tool 300psi. I know you going to grindge but it is a Haas VF6 2009 model.

[Greg_J]

What size holes are you drilling?

 

I'm working on Incoloy 925 NACE and I'm using solid carbide with through coolant, I have 150 psi no high pressure. I used 50 sfpm .002 per/rev.

 

The part I'm working on right now has a 3.5 dia hole, 16.25 thru the part, I was planning to use a 2.0 indexable drill and then helix bore the hole from both sides.

[Superman]

In100 speeds/feeds

Drilling 3.3mm with SECO SD205A-3.3-21-6R1

22 m/min = (2341RPM) @ 0.05mm/Rev

Drilling 6.8mm with SECO SD203A-6.8-25-8R1-M

20 m/min = (936RPM) @ 0.069mm/Rev

Thru coolant, no pecking

 

Drills are TiAln+TiN coated

for Inconel718, increase surface speed only( 10-30%), keep the feed/rev about the same

[Matt Boozer from L&R PT]

Our hole sizes are on the average of .125 and 6" inches deep.