What type of machine is best for small holes in carbide?

The answer is...it depends!

Quality starts in the preparation

Sometimes, care must be taken to:

• protect surface integrity
• ensure precise location
• manufacture a straight, accurate hole that does not walk or bellmouth

There are two major things to consider: If there is some room between the start hole and the working edge of the carbide tool, then hole quality may not be so important. If hole quality is vital and parent material damage cannot encroach into the working edge of the tool.

For start holes where hole quality may not be so important (#1 above), you should consider a dedicated hole drilling EDM machine.  Here are the considerations and benefits of using a dedicated hole drilling EDM:

• Slightly more difficult to control surface integrity
• Designed specifically for hole diameters between 0.007" and 0.125"
• Accuracy is acceptable for all but the most demanding applications
• Low investment cost and fast setup

For start holes where hole quality is vital (#2 above), a high performance die-sink EDM system with fine drilling capability is the best solution.  Here are the considerations and benefits of using a high performance die-sink EDM with fine drilling capability:

• Faster than hole drilling EDM in small diamter carbide holes
• Excellent accuracy, less change of parent material damage
• Designed specifically for hole diameters between 0.005" and 0.125"
• Can be used as a standard die-sink EDM

Using a die-sink EDM with fine drilling capability, you can also go from small hole configuration to die-sink with little effort.

Here are some machining results for die-sinking with fine drilling option*

*Results were captured on a GF AgieCharmilles Form 20 die-sink EDM with FD (fine drilling) option. 

Here are some machining results for hole drilling EDM in carbide**

**Results were captured on a GF AgieCharmilles Drill 11.

In Summary

Small hole drills:

• Require smaller investment
• Use only water as dielectric
• Take up less floor space
• Have faster set-up time

Die-sink EDMs with Fine Drilling:

• Require larger investment
• Are more flexible
• Are more precise
• Use oil as dielectric