Problem- - Machining of Inconel 718

[Naz78]

Hi guys,

I am new here (yes of course!)

Am trynna help a supplier of mine in machining a cylindrical hollow piece of Inconel 718.

There's a callout for 7 holes-in-a-series that goes 12 times all around the component.

One of my supplier states that he cannot achieve 7 holes in a series with each hole having a tolerance of +0.020mm/-0.000mm and mentioned that he could achieve it if I expanded the tolerance to 40 microns instead.

Is there anyway I could assist the poor chap in his parameters or something?

Or is this a definite case with Inconel 718?

[Cmailco]

What size are the holes? What are the other requirements; ie, true position, etc?

Thanks,
Chuck

[titan99]

Inconel-718 can be very challenging to drill due to the high nickel content.

If the material is in aged condition- AMS 5663, it will be even more difficult.

If the part permits, you can change the process to EDM.

Or Inconel-600 could be an easier alternative than 718 grade.



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[PixMan]

That is a very tight tolerance for a drill. Too tight, if you ask me, in that material. It's possible in many aluminum alloys, but not in that high temperature alloy.

What is the depth of the hole, the diameter, and is it a through-hole or a blind hole? Condition of the material is important too. I find it machines a little easier if heat treated to 28 to 32 Rc hardness.