Designer seeking Mfg. input 1

[DJKeng]

Gentlemen,

Can an EDM process be used for producing a sharp inside corner (.002 max R) within a blid hole?

The hole is about 3.5" diameter and 3.5" deep.

Thanks for the help!
djk

 

[looslib]

It has been years since I did anythimg with EDM, but that seems like too tight of a radius. You might get it with a second electorde burn, but the elctrode burns fastest on the sharp corner.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand

 

[bradphillips]

Just curious.
Why do you need a .002 max radius in a blind hole?

 

[DJKeng]

Cast pump design(simplified) is currently 3 piece design. I.E., a housing with a through hole and a seal w/ endcover at both ends.

I'd like to be able to eliminate a leak path and save money by making the pump a two piece design. I.E. one housing with blind hole and one end cover. A sharp corner is required to help prevent an inefficient pump.

 

[jjj647]

It can be done using conventional EDM's. However it would be very difficult, expensive and time consuming to produce. From a manufacturing engineering standpoint I would not recommend it. The 0.002 max radius is difficult to maintain regardless of what process you use. Might be worth looking into for a few pieces, but not for mass production.

 

[rhodie]

Are you planning on using a graphite or copper electrode?

 

[DJKeng]

I don't know about the electrode material.

I was really just wondering about process capability. I googled all over for edm references but found nothing concerning sharp corners within blind holes.

 

[bvasa]

What about making the hole oversize and pressing in a pre-sized cylindrical liner? The OD of the liner could be chamfered to accomodate whatever corner radius you produce on the receiving bore. The inside corner of the liner, where it meets the bottom of the receiving bore, would be sharp or slightly undercut.

 

[DJKeng]

That would work, but adds another part. But that solution does eleminate a leak path... A cost analysis would need to be done. Hmmmm...

thanks all.

 

[Kapitan]

Add an operation to the Boring/Turning machining process, to put a minimum undercut into either the sidewall or bottom face of the bore. There is plenty of room to get a tool into corner and it would be cheap to do.

 

[timbarnett]

What is stopping you from machining it?