Turning Inconel 625

[KLP1190]

I am working on a part made of Inconel 625 that is giving me a hard time. 

The hole needs to finish at 0.441 Diameter. My initial plan was to drill the hole then ream to finish. I just keep burning up my drills. So far I have trashed a solid carbide drill and a firex coated cobalt. The last tool I burned up was the firex coated cobalt. I was running it at spindle speed of 350, 0.0045/ Rev, 40 SFM with a 0.650" peck. I am chip breaking but I am not dwelling. 

If anyone has any input it would be much appreciated.

TIA.

[nickbe10]

Through spindle coolanrt and no pecking is the only way to go with Inconel, how deep?

[KLP1190]

Any alternative ideas? The lathe I am on does not have through tooling coolant. 

[nickbe10]

How deep?

[KLP1190]

Sorry, it has to go 2" deep. 

[crazy^millman]

You can rig your lather tool to do through the tool. Put a Pip plug cap on the back of the socket and pipe the coolant from the turret. You are work hardening the material. If you are going back in the same part you are toast. That part is gone more than likely you must use the right tool and process for this material. You are not and you are doomed to fail unless you adapt to what you need. Work hardening this material is what most people do and then they keep chasing the hard spot.

[KLP1190]

Thank you all for the input. It's really appreciated. 

[nickbe10]

In addition to Ron's advise the material is TOUGH, so it does not want to make a chip. Constant starting of the chip accounts for a lot of wear and work hardening finishes it off.

Technically you could try 3.5 D initial peck and then .5 to 1 D until finished, but it won't be much fun. Good quality drills are a must.....Mikron, Sphinx, Guhring......

I would go with Ron's suggestion of rigging up a TSC with some plumbing......

[mkd]

35% less sfm and less chip load

must rig up coolant per Ron.

[Colin Gilchrist]

I'd try 25 SFM, .003 per Rev.

Do a .500 peck, and throw a 2-3 second dwell to get coolant in the hole and cool the drill. That's 4 pecks per hole...

What kind of coolant port does the turret have? I recently had to rig up some external coolant hoses on a lathe. The connection in the tool mounting block was a 14mm sphere. So I ordered some brass balls with copper tubes, that are 6 inches long. Then I ordered some hydraulic tubing, with stainless 1/8 NPT fittings. I had one of our maintenance guys braze the copper tube into my hose fitting, and it was easy to make the connection. Once I was able to get coolant to the tool tip, all my issues went away...

[Colin Gilchrist]

Global CNC also has ID bushings with NPT ports in the rear...