how fast is an edm hole?

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memphisjed

Titanium

Joined

Jan 21, 2019

Location

Memphis

• Aug 24, 2021

• #1

Yesterday I was asked about "how could you" drill a 1/16 hole thru 2 1/2 inches of steel [astm36]. Accuracy on diameter is +- alot, alignment top and bottom is say 1/32". Of course you can drill both sides and then run a bigger drill thru the hole (surface finish does matter a little) to ream it out.
But I was wandering if a edm drill could do it in one shot, and how long would it take?

 

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MaxPrairie

Hot Rolled

Joined

Jul 9, 2015

• Aug 24, 2021

• #2

I have done a 1/32 hole 1” deep so I don’t see why you couldn’t do this. Pecks were only 10 thou but it got done. Edm I would think would be slower…

 

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SeymourDumore

Diamond

Joined

Aug 2, 2005

Location

CT

• Aug 24, 2021

• #3

1.5mm electrode, steel .. somewhere in the 'hood of .6-.7" per minute.
Hole will be straight, but it will have a bit of taper on the end, and a slight overburn at the beginning.

Stainless would be quicker, perhaps 1 - 1.2" per minute even.

 

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memphisjed

Titanium

Joined

Jan 21, 2019

Location

Memphis

• Aug 25, 2021

• #4

thank you

ps words word words making count limit

 

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Luke.kerbey

Guest

• Aug 25, 2021

• #5

To take a stab at time, in best conditions 4 minutes, bad conditions 8 minutes on our Sodick CNC EDM hole driller. However you couldn’t ream the hole after as the surface will be hardened, if you needed a better finish.

 

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SeymourDumore

Diamond

Joined

Aug 2, 2005

Location

CT

• Aug 25, 2021

• #6

Luke.kerbey said:

However you couldn’t ream the hole after as the surface will be hardened, if you needed a better finish.

Click to expand...

No it won't be hardened!
Never in 20+ years have I seen a popped hole that was not possible to ream, even with HSS!

 

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Luke.kerbey

Guest

• Aug 25, 2021

• #7

Not as in through hardened the area around the hole, but it will leave a hardened skin, the coarser the finish, the harder the surface.

I’m sure it’ll ream if you take a decent cut under the skin.

 

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MaxPrairie

Hot Rolled

Joined

Jul 9, 2015

• Aug 25, 2021

• #8

Just got done doing a 50 thou hole 800 deep with 15 thou pecks. Minute and a half in a36.

 

White Lightning

Aluminum

Joined

Jan 21, 2018

• Aug 25, 2021

• #9

MaxPrairie said:

Just got done doing a 50 thou hole 800 deep with 15 thou pecks. Minute and a half in a36.

Click to expand...

.800 deep compared to 2 1/2 is apples to oranges.

Sent from my SM-G960U using Tapatalk

 

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SeymourDumore

Diamond

Joined

Aug 2, 2005

Location

CT

• Aug 25, 2021

• #10

Luke.kerbey said:

Not as in through hardened the area around the hole, but it will leave a hardened skin, the coarser the finish, the harder the surface.

I’m sure it’ll ream if you take a decent cut under the skin.

Click to expand...

There is recast layer, and there is HAZ ( Heat Affected Zone )
The recast layer is easily removed no matter how hard it is, simply because it is - for all intents and purposes - little solidified pebbles that got re-deposited on the surface of the hole.
They have absolutely no strength to hold onto that surface, so it's easily removed.
The HAZ is a different thing altogether, It isn't hard, nor is it thick. It is simply a layer that may or may not have surface cracks. Other than that is is easy to remove.

In fact, the biggest BITCH of a material to ream out after EDM drilling is Aluminum!
And that is because the recast layer is thick as shit, and it is CERAMIC!!!

Reaming out a small amount of A36 after holepopping is a breeze.
So is A2, D2, CPM10V or any other tool steels or stainless steels.

 

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MaxPrairie

Hot Rolled

Joined

Jul 9, 2015

• Aug 26, 2021

• #11

White Lightning said:

.800 deep compared to 2 1/2 is apples to oranges.

Sent from my SM-G960U using Tapatalk

Click to expand...

Just saying it’s not that big of a deal to do. He said he could do it for both sides also so it is more like apples to pears.