should I peck drill in 6al4v ti with tsc

[Bluejeep]

Now that I have a machine with tsc I am reevaluating some of my existing programs that didn't have tsc . I have a part from grade 5 titanium which I drill 2, 3/8"dia. holes 7/8" deep. before I would peck drill with ample flood coolant. This worked ok until it doesn't. Now that I have tsc I picked up a kennametal go drill with thru coolant holes. should I continue to peck with tsc?

 

[Bluejeep]

I Just got a reply from Kennametal tech support. they don't recommend pecking with any of their drills.

 

[DouglasJRizzo]

I Just got a reply from Kennametal tech support. they don't recommend pecking with any of their drills.

I'd go with their advice. Pecking with that type of drill can lead to damaging the drill and work piece. A steady drilling motion will yield better results. I think they like a "soft start" with those, too.

 

[mhajicek]

No need to peck with a TSC drill, provided you have enough TSC pressure. The smaller the drill, the more pressure you need. Your tools will last much longer without pecking.

 

[Milland]

It sounds like these are blind holes. If you do through holes, it might be worth slowing the feed for the breakthrough - check with your applications guy.

 

[Bluejeep]

It sounds like these are blind holes. If you do through holes, it might be worth slowing the feed for the breakthrough - check with your applications guy.

They are thru holes

 

[Pfmarkeytoolguy]

Almost never peck with TSC drills. Pecking is death to carbide drills, they don’t like the impact. Now milland is correct best practice is to slow the feed right before the tip is about to disengage, this will help preserve the corners of the drill on break out.

 

[Rick Finsta]

Or you can use drills with a cast iron geometry (corner radius or chamfer) to protect the drill during breakthrough. It will raise much more of a back-burr, though.

Never peck with TSC unless you are in a pinch and need to get a hole to come in to a size and pecking is the only thing that works.

 

[mhajicek]

Never peck with TSC unless you are in a pinch and need to get a hole to come in to a size and pecking is the only thing that works.

That's what reamers are for.

 

[dstryr]

The kennametal Go drills are a unique carbide drill with no margin. You can peck them just fine and we do it all day long in 316 , Titanium etc. Hard to break chip deeper holes .

A lot of the time we are pecking we are going just slightly passed the "drill depth" of the drill but trying to avoid going from 5x to 8xd for example.

That being said I wouldn't peck a 3/8 Go drill at 7/8 deep in Titanium.
Just run the drill per the chart SFM and IPR.
I've had such great luck with the go - drill that we try to use it on everything.