Drilling on Doosan Puma 3100LY

[JeremyV]

I have a stainless cylinder that is 9" od x 4.4 long solid block and would like to try to attempt drilling with a 2.875 OTM drill....

 

 

Question is.... will the turret break trying to handle that big of a drill or?  I know the machine has 887 ft/lbs of torque on the spindle... but I wondered if anyone else has suggestions?

 

I do need to bore to 7.11 ID....

 

-JD

[gcode]

My experience with Pumas is that they do not have enough Z thrust to drive a drill that big

I did a lot of work on a Puma 200 slant bed and it would alarm out with a Z axis overload alarm

running an Ø1.375" spade drill in mild steel.

My advice is send the blank out to a gun driller or trepanning shop

[JeremyV]

Ah wow.... interesting.

 

From what the machinist tells me, we've been using the 1.85" Seco drill without any issues on the machine.  He did say the servo loads were pretty low, didn't really pay attention to them. I did verbally slap him for that lol, but this Puma is a 2015 model and on their brochure, they've updated a lot of their hardware on these so I would imagine the 3100 is a heavy duty lathe... hmmm

 

We did however use a 3.875 dia OTM drill on the Doosan Mynx 7500 with ease on a cylinder part to bore a hole out for the lathe.

[jlw™]

Do you have C or Y axis? Helix bore it of you do.

[gcode]

The machine I ran was  mid 90's  vintage... and very accurate ... it didn't like to drill big holes though

I guess all you can do is try it and watch the servo loads.

Your other option would be to get an Ø1.500 hole through it and blow the stock out with a short Ø1.25 boring bar

That would take a little longer but be much less stressful on the machine

[Matthew Hajicek - Singularity]

Set it up on a mill (preferably horizontal) and helix bore it with thru-coolant.  Leave a little stock to clean up on the lathe for size and location.

[civiceg]

^^^High feed mill ftw

[GoetzInd]

I've pushed a 2in indexable drill on a 2000SY no problem. 2.875 may be possible on your larger machine. However, I would do like others have suggested and either drill with something a little smaller and bore, or helical open. The problem with milling it open is your live tooling unit will not do well with a tool that can do this efficiently so it will most likely add an operation.

 

Mike

[Mike@Lustre]

what grade of SS is the part ?? we drill 303/304 with a 1" KSEM drill all day , run about 900rpm with .012" feed rate . last shop I was at we pushed a 2.375" U drill thru 4140 ( can,t remember if it was ANN or HTSR ) on a HAAS ST-20 with no issues so I would think a PUMA should do similar assuming the material is not 316 or better grad wise .

[JeremyV]

what grade of SS is the part ?? we drill 303/304 with a 1" KSEM drill all day , run about 900rpm with .012" feed rate . last shop I was at we pushed a 2.375" U drill thru 4140 ( can,t remember if it was ANN or HTSR ) on a HAAS ST-20 with no issues so I would think a PUMA should do similar assuming the material is not 316 or better grad wise .

 

304 / 304L SS

 

Set it up on a mill (preferably horizontal) and helix bore it with thru-coolant.  Leave a little stock to clean up on the lathe for size and location.

 

Well... can't helix bore with an OTM drill nor pre-drilling as they don't recommend such applications.

 

Do you have C or Y axis? Helix bore it of you do.

 

We do have a Y axis.

 

 

 

I'll let you all know how this drill performs - will start cutting  chips within the hour or so

[gcode]

If this is a big production run, trepanning is worth looking at.

They typically use a 1/4" wide core drill and I'd trepanned this job to Ø5.5" ID

The advantages are

You don't beat up your new machine doing heavy roughing

The machine is free to do other  more profitable work

When you get your trepanned parts back, you'll also get back clean Ø5" slugs

you can use to build other parts

[JeremyV]

If this is a big production run, trepanning is worth looking at.

They typically use a 1/4" wide core drill and I'd trepanned this job to Ø5.5" ID

The advantages are

You don't beat up your new machine doing heavy roughing

The machine is free to do other  more profitable work

When you get your trepanned parts back, you'll also get back clean Ø5" slugs

you can use to build other parts

 

This is very true, we do practice trepanning and use it often as needed.

 

However, we are drilling 4.8" deep on a blank slug.

 

 

 

Anyway.... results are in!

 

Machine survived..... wow.

 

300RPM .002 IPR

 

Spindle load: 23%

Y servo load 75% ( 67% just sitting doing nothing )

Z servo load 64%

 

it worked out pretty good.