We started running into a pecular problem, and we don't seem to be able to solve.

One of the opartions calls for a hollow point to be drilled into the nose of the bullet.
Drills used to last a few thousand bullets before one breaks.

Now we have one break on every bullet!!??

Any suggestions would be greatly appreciated.

What has changed, anything?

I am supposing the feed and rpm's have remained the same as the pre-breakage batch?

I know you have done this already, but I would look at the basics first- is the drill bit misaligned at all, did you change the material used in the bullets, are the drill bits reground differently?

Do you use a lubricant/cutting fluid?

Did Walter rewire the lathe from 60 cycles to 50 cycles?

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What has changed, anything?

Look over the code to see if there's something not visually obvious during the cycle.

Did you switch brands or types of bits ..??
That's the only problem we see when doing the same operation here. Also trying to drill the HP too deep breaks the bit off. Small carbide screw machine type bits can stand little to no perpendicular loads (they'll snap off very time).

Make sure someone didn't screw up your collet too ...

check your drills ,make sure they're not left hand and the lathe is spinning in the correct direction...it happens
Bill

Have you had a crash? Turret could be off. Debris in the drill chuck may affect the centering of the bit. I think the other guys have covered just about everything else. Did you switch brands of drill bits? Do the bits have proper clearance and rake angles? Is there a taper in the bits? Using a Co-Axial indicator in the lathe chuck at a very slow RPM measure the runout in a guage pin held in the drill chuck.

Andy B

I cannot see anything has changed.

We are using the same drill bits.

But, I am going to take that chuck apart and clean it.

I will let you know how that goes.

Thank you for all your suggestions.

This may sound a little naive, but is the material up to original specs?, I have experienced a lot of sub standard materials over the last few years as cost cutting sets in big time, I've busted many drill bits/punches etc, on hard spots.

Problem solved!!

You know, any time Walter gets involved in anything, something is bound to go wrong!

I mark the drills with a marker pen of how far into the chuck they sit.

We bought a new pack of drills, and I marked one and installed it.

While doing that, Walter proceeded to mark the rest.

The one I marked has worked for a long time, and every since I have been using the ones he has marked, they break!

Guess what?

He marked then WRONG. Just a little, but still a tiny bit too long.

So as the chuck rotates to get into position to drill the hole, it hits the end of the bullet!

I replaced one just now, and set the machine on slow feed.

I saw what happened, checked the drills, and marked one myself and put in.

Every bthing works like a charm now!!

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So as the chuck rotates to get into position to drill the hole, it hits the end of the bullet!

That'll usually do it.

The Walterhog factory is back on line then ...

Man! Talk about the "Odd Couple"!!

Tell Walter not to quit his day job! Does he have one?

Rich
Buff Killer

BTW, Are you able to turn you lathe fast enough for optimum SFM for you drill and material?

Some of the parts manufactured in my industry are gas diffusers that will have 10k to 20K holes per part that vary from .024 down to .008. With proper drill point geometry the suppliers can drill a complete part with one drill.

It is normal practice when you break something to touch the tool off the face of the part and set the Z face zero. Your program probably reads like this on the first command line; G0 X0 Z.05 M8, this means the drill is starting it's Z- move .050 off the face of the part, then you will see something like G1 Z-.150 F.004, then G0 Z.05 M9. The F.004 would be the feed rate, M8 turning on the coolant and M9 turning it off, Lastly the machine needs to go to a point where it will be safe to rotate the turrent for the next tool the command for which will look like this; G0 G40 X8. Z8., numbers which you will have to calculate depending on your longest tool which is usually a big drill or boring bar. However if you aren't touching off every time you change your drill and depending on a mark on a drill bit then the depth of the hole will vary by an unnaceptable amount, easily more than .01. Which means you will be fired if you don't start getting it right.