WireEDM - Internal Machining Without Entry Cut

[flamemaster]

hi can someone tell me when using wireEDM to machine a part that when you need to remove material from the inside without creating a entry cut from the outside how will you make a starting hole to thread the wire in, will i have to drill a hole in it to thread it? but i have seen some videos on the net that they can remove material from inside using wireEDM which have like 40+ inches of height of solid material, and didn't have any outside entry cut.

much appreciated

 

[Baluncore]

I find it hard to believe that the wire is being used to pilot the starter hole. The wire is only about 0.3 mm diameter and could not be directed straight through a 40” workpiece. While pushing the thin solid wire, the dielectric flush would not be able to penetrate the blind hole.

Wire EDM is advancing rapidly. Today's machines thread their own wire through the starter hole. You may not have noticed a small starter hole while the machine is auto-threading through the hole.

Gun drilling is capable of making a small accurate starter hole. Maybe the starter hole has been drilled using Ram EDM which gently feeds a tube electrode into the conductive material. The tube electrode carries the dielectric flush and is usually consumed at about twice the rate the hole is made.

 

[flamemaster]

yeah thanks for the reply, i asked my supervisor and he told me that it was small hole EDM was used to create holes.

 

[Baluncore]

Thanks for the confirmation.
The great thing about EDM is that it can accurately drill and cut the best quality tool steel and conductive carbide components.
Unfortunately, with brass wire consumed at a speed measured in metres per second, it is not for the faint hearted amateur experimenter. Enjoy the EDM magic while the customer pays.