Burn out drill bit

[bob]

Broken #57 bit. Tried graphite no joy. Tried fine brass burned electrode burned el faster then bit. Friend suggested ccopper so ordered 1mm electrode with hole for flushing but not real optimistic. I guess the real answer is dont break the bit but thats a tall order maybe just abandon the project, any suggestions?
Bob

 

[memphisjed]

PCb carbide bit to get most of it? They are dirt cheap if it doesn’t work.

 

[SteveEx30]

Im guessing its a carbide drill?

I get drills/taps all the time from customers, that should be fairly simple to get out.

If your trode is wearing that fast your settings are wrong. Use Copper tube, High IP, Low ON, Neg Polarity.

What EDM machine?

 

[bob]

This is antique D10. Tried circuit board drill but they are so fragile will break immediately.

 

[implmex]

Hi bob:
Often there will be chips packed in the hole and there will be shattered pieces of drill too.
If they flop around while burning they will short the trode and stall the burn.

If that's your primary problem you have to be patient and pick or blow out the bits as they come free.

If your principal problem is that you are consuming a lot of electrode for no gain then SteveEx30 has put his finger on it and your settings are wrong.

I do best with a small copper tubing trode poked down under relatively high power and using reverse polarity as Steve recommends.
Tubing trode is cheap so I don't care how much I use up.
I prefer the coreless trode and I rotate it with a Rotobore and use moderate flushing pressure.
I let it wobble a couple of thou so it burns a bigger hole than a concentric trode would.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[SteveEx30]

This is antique D10. Tried circuit board drill but they are so fragile will break immediately.

And that's fine, the older machines work well for this type of work once you dial em in correct.

You didn't confirm if the drill is Carbide or HSS. Makes a big difference for settings.

. High power, low ON, ramp the OFF up until it burns steady.

 

[Waakzaamheid]

Assuming you are trying to burn this out with a regular sinker? Because I would do things like this all day long using a hole popper/small hole EDM. If it's carbide you would use copper, brass otherwise.

Essentially what Steve said.

 

[SteveEx30]

Assuming you are trying to burn this out with a regular sinker? Because I would do things like this all day long using a hole popper/small hole EDM. If it's carbide you would use copper, brass otherwise.

Essentially what Steve said.

Hole popper is like cheating lol
But most definitely if he has one.

 

[tvalen1432]

How does one survive EDM without using a hole popper? LOL. I burn out what ever the guys can break with mine and copper tubing w/ flushing threw the tube and an additional flush outside. Correct settings are a must.

Tvalen1432

 

[bob]

I knew the electrode was too big but it was the smallest copper with hole that i had and the part was scrap so tried it just to see if it works. Managed to get trough it so I think when I get the proper electrode should be ok. Thanks to all that responded and to Jens in Oz who sent suggested settings.
Bob