Deep drilling suggestions

[medaq]

Hey guys,

 

Have some deep holes to drill in 3 seperate parts all the same hole and nearly the same depth.

 

The hole is .159 dia and the deepest is 8.5".

 

Now drilling it is no problem, we have a gun drill lined up to stick in the horizontal right now. We have 800 psi and can do it in one peck at 1.5 ipm. Which is going to take over 5 minutes a hole. With about 20,000 holes to do I am looking for a more efficient way to do this. I was thinking with even a air craft drill pecking material might be faster, but how much time am I going to lose rapiding in and out of the hole to clear the chip over keeping the gun drill at a constant feed through the part.

 

If anyone has any recomendations to look at it would be much appreciated.

 

Jim

[jrauch]

Hello Jim, Whats the material???

[medaq]

Sorry that was a key piece of information.

 

6061 t6 aluminum

 

Jim

[jrauch]

Feed rate seems a little slow... whats your max rpm of your machine. I just ran the numbers and with a single lip carbide tip gundrill rpm is around 14,400 and the feed 2.8 imp. Thats at the low end.

[DavidB]

I had a guy from Titex Germany here last week regarding this subject.

They now have 30 x D carbide drills off the shelf.

We drill a 6mm hole in PH15-5 S.S 160mm deep thats 27 x D.

The method is..

Drill a hole 1 xd deep with a stub drill the key here is to drill a hole with the correct tolerance you need a (M7) fit.

Now with the Long carbide drill reduce feed and speed by 50% and cut 1mm deeper than the pilot drill,increase feed and speed to recomended and drill to full depth no peck. Stop the spindle at full deepth and retract the drill.

Do not have the spindle running when Rapid traversing with the tool in spindle or have the through spindle coolant on while not in cut!

 

HTH

[medaq]

quote:

---

Feed rate seems a little slow... whats your max rpm of your machine. I just ran the numbers and with a single lip carbide tip gundrill rpm is around 14,400 and the feed 2.8 imp. Thats at the low end.

---

Well we have a 15k spindle on the machine, I was just quoting the numbers the gun drill company recomended. He said with 1300 psi I can get away with 3.0 ipm at 10,000 rpm but with our limited coolant to cut the feed in half. I can probably bump the rpm to 15k and go f2.25 at their minimum recomendations.

 

And dave thanks for that tip, I will contact titex see if they have any longer options, Being 30x.159=4.77 makes my target length a little short atm.

 

Jim

[DavidB]

I just check mate they have 30 x D 6mm dia and over. Under 6 dia they have 20 x D.