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Large Insert Drill in Aluminum Issues

Rick Finsta

Stainless
Joined
Sep 27, 2017
So, I've been running an Ingersoll 2" diameter 3xD inserted drill, that takes the square inserts (inside and outside are the same) to rough holes in 2"x8" aluminum extrusion (6061-T6511). I have been running 2000SFM and 0.011ipt (21.45IPM) for a long time now using flood coolant. Machine is an Okuma bridge mill (560-V) and I am using a standard (not dual contact) 1.5" sidelock holder.

Well, I just hooked up through tool high pressure coolant and have had my first issues with this tool. When the drill gets to the bottom of its travel (0.125" below the stock bottom)I had it chatter when it goes to rapid back up and dig in enough that it lifted the part slightly (a few thousandths). This happened on the same piece of stock twice in a row even after I reset the material, retightened, and then probed the stock back in.

The material is 20" long and sitting between two Orange vises. I double checked the tram prior to trying it a second time and it was good. I stuck some paper shim between the moving jaws and the stock and went back to flood coolant for the last hole. I am using 4140PH shop-made step jaws that grip about 0.780" deep and they must be smooth as OP2 I flip over the part and grip on the final profile.

This is my bread-and-butter part so I need to figure this out.

Is this something that changed when using high pressure through coolant that could be destabilizing this drill with this stickout? Is it the stock extrusion is not square enough and I'll need to use paper shim on this lot?

The plan was always to move to a 2xD drill and dual contact holder for this but I was hoping to space out the new tool purchases (to utilize the TSC) over the next few months to soften the hit on the budget.

Anything I'm not seeing here? I have some drops from previous lots of raw stock that I guess I could compare for squareness. Any other ideas?

I simply cannot afford to have a part lift on this drill - I know it would completely wreck my spindle. Worst case I can go to punching a through hole with a smaller drill and roughing with another tool (helical boring).
 
So, I've been running an Ingersoll 2" diameter 3xD inserted drill, that takes the square inserts (inside and outside are the same) to rough holes in 2"x8" aluminum extrusion (6061-T6511). I have been running 2000SFM and 0.011ipt (21.45IPM) for a long time now using flood coolant. Machine is an Okuma bridge mill (560-V) and I am using a standard (not dual contact) 1.5" sidelock holder.

Well, I just hooked up through tool high pressure coolant and have had my first issues with this tool. When the drill gets to the bottom of its travel (0.125" below the stock bottom)I had it chatter when it goes to rapid back up and dig in enough that it lifted the part slightly (a few thousandths). This happened on the same piece of stock twice in a row even after I reset the material, retightened, and then probed the stock back in.

The material is 20" long and sitting between two Orange vises. I double checked the tram prior to trying it a second time and it was good. I stuck some paper shim between the moving jaws and the stock and went back to flood coolant for the last hole. I am using 4140PH shop-made step jaws that grip about 0.780" deep and they must be smooth as OP2 I flip over the part and grip on the final profile.

This is my bread-and-butter part so I need to figure this out.

Is this something that changed when using high pressure through coolant that could be destabilizing this drill with this stickout? Is it the stock extrusion is not square enough and I'll need to use paper shim on this lot?

The plan was always to move to a 2xD drill and dual contact holder for this but I was hoping to space out the new tool purchases (to utilize the TSC) over the next few months to soften the hit on the budget.

Anything I'm not seeing here? I have some drops from previous lots of raw stock that I guess I could compare for squareness. Any other ideas?

I simply cannot afford to have a part lift on this drill - I know it would completely wreck my spindle. Worst case I can go to punching a through hole with a smaller drill and roughing with another tool (helical boring).

Do you have serrated jaws? What about using a spade? 2000sfpm sound high to me.
 
Something doesn't add up with your feeds and speeds. Do you mean 2000 rpm?
 
Well, I just hooked up through tool high pressure coolant and have had my first issues with this tool. When the drill gets to the bottom of its travel (0.125" below the stock bottom)I had it chatter when it goes to rapid back up and dig in enough that it lifted the part slightly (a few thousandths).



Is this something that changed when using high pressure through coolant that could be destabilizing this drill with this stickout? Is it the stock extrusion is not square enough and I'll need to use paper shim on this lot?


Anything I'm not seeing here?

It sounds like the drill is walking maybe? I've never liked the square insert drills and TSC shouldn't have anything to do with it. At least I've never heard of that influencing a drill especially of that size.
One of my all time favorite indexable drills is the Magic Drill from Kyocera.
They're cheaper than Sandvik and other big name brands usually.
Carbide depot has a 2" 2xD for $600.00
Not cheap by any means but they cut like butter.
 
1000 sfm makes more sense.

I don't see how the high pressure coolant would cause this problem. You've made a lot of parts with the same parameters but with flood coolant?

Is .011 ipr what's recommended for that size drill? It seems high to me, but I don't know what drill you're using. Maybe it's fine.

This is a blind hole, right? Do you have a dwell programmed at the bottom before the retract?

Is the drill cutting to size? Inserts in good shape?
 
It's counterintuitive, but why not try just using flood coolant again for the drill op, and see if it behaves correctly (doesn't pull the stock up)?

Could there be something weird like the through coolant allows closer to-size cutting, but then there's more drag on the inserts during rapid up? Maybe the flood coolant method cuts slightly oversize, lowering drag in Z clear.

Other possibility is this stock is softer, with more BUE acting to increase drag?

Just some WAGS...
 
Yes I've drilled over a thousand holes with the flood coolant and same speed/feed.

Drill is an Ingersoll Quad Drill Plus, P/N Q0508152N7R01 using a Sumitomo insert (the old owner of the product line bought a drill that fit inserts he already used for face milling but was never really able to run the drill due to not having the TQ/HP).

0.016" feed per rev is what is recommended for this drill IIRC, but I was not able to push it harder than 0.011" with flood coolant since the high RPM was limiting the amount of coolant getting to the cut. I was getting hot chips and some chip welding.

Inserts are looking good - I rotated them last week sometime and they have so far gone about 6-8 months between rotation.

Hole is a through hole.

Hole has always cut rough and a bit oversized but it is just a starter hole for me to drop a 4fl 1" inserted cutter down and get to work.

The only differences are the new lot of extrusion and the through coolant. I drilled four holes successfully the day before on the last of the old lot of aluminum so I'm leaning towards that but just wanted to know if there is something the coolant could be doing to change things.
 
It's counterintuitive, but why not try just using flood coolant again for the drill op, and see if it behaves correctly (doesn't pull the stock up)?

I did this for the last hole on the part that was giving me issues yesterday but I also had the paper shim in the vise. I may just run this lot with shim and see what happens, but I don't like the idea of experimenting with a $20k+ spindle on the line. LOL
 
Rick
use alum jaws steel ones suck and have less grip then alum jaws especially if there nice and smooth, the other issue is unless your parts are trued and square on the sides and facewhere it locates your going to have issue.
 
Just weird that I haven't had any issues until now, and I've gone through dozens of lots of material. It seems to be grabbing on the retract so I'm thinking feeding back up is my next best bet. If I wasn't so scared about fucking up my spindle I would try and handful of things to nail it down.

I use the steel jaws because when I flip the part I try to hold <0.001" flatness and parallelism with the opposite surface. Easy enough to do with parallels but then I'm fiddle fucking with those all day. I haven't had luck with aluminum step jaws lasting long or holding parallelism. But I also don't really know what I'm doing LOL.

Also just spoke with the Ingersoll rep and the old owner may have put the wrong inserts in there. Evidently the insert pocket is proprietary and the Sumitomo inserts should not fit correctly. Again, not sure why I'd have problems now. I'm leaning towards some of Milland's thoughts because it seems to be fine all the way to the bottom of the stroke.

That or the TSC is making it hit some weird harmonic and rattling it on retract.

Ingersoll rep is going to stop in on Monday - I've got plenty of tax paperwork to do for this afternoon anyways (uuuuuuuugh).

I welcome any other thoughts and experiences! I appreciate the insight.
 
I completely failed to see this in your OP.
Hopefully the correct inserts will fix your issue.

They might not be those inserts - they look the same, but they were in the drill when I bought the company and I've only ever rotated them.
They are on their last rotation now and I was going to call Ingersoll anyways to see about what to put in there. They may just be the only ones he had without a box of spares since he never really used the drill.
 
How high a pressure you running that at? A big drill like that drilling only one diameter could do perfectly well with 200 - 400 PSI easy. Especially considering how well you've done with outside coolant delivery. Besides... no sense wearing out your HP unit when you don't need 1000psi.

That drill has a pretty flat tip so there's no reason to go a full 1/8" past thru. I'm figuring the less the drill exits out of the hole the less there is to catch on something.

I can't imagine not, but is there an escape route for the HPTSC once it breaks thru?

Do you have a cylindrical or precision square to check the tram of the Z axis?

Looking at the F&S sheet on your drill, it looks like in wrought Aluminum they're recommending 1000-1300 SFM and 0.006-0.010 ipr. I find the the insert drills leave a pretty clean hole. If yours are pretty rough as you say it might be that high-ish feed rate.

Just thinking out loud. Hopefully the rep will have some good ideas next week.
 
So, I've been running an Ingersoll 2" diameter 3xD inserted drill, that takes the square inserts (inside and outside are the same) to rough holes in 2"x8" aluminum extrusion (6061-T6511). I have been running 2000SFM and 0.011ipt (21.45IPM) for a long time now using flood coolant. Machine is an Okuma bridge mill (560-V) and I am using a standard (not dual contact) 1.5" sidelock holder.

Well, I just hooked up through tool high pressure coolant and have had my first issues with this tool. When the drill gets to the bottom of its travel (0.125" below the stock bottom)I had it chatter when it goes to rapid back up and dig in enough that it lifted the part slightly (a few thousandths). This happened on the same piece of stock twice in a row even after I reset the material, retightened, and then probed the stock back in.

The material is 20" long and sitting between two Orange vises. I double checked the tram prior to trying it a second time and it was good. I stuck some paper shim between the moving jaws and the stock and went back to flood coolant for the last hole. I am using 4140PH shop-made step jaws that grip about 0.780" deep and they must be smooth as OP2 I flip over the part and grip on the final profile.

This is my bread-and-butter part so I need to figure this out.

Is this something that changed when using high pressure through coolant that could be destabilizing this drill with this stickout? Is it the stock extrusion is not square enough and I'll need to use paper shim on this lot?

The plan was always to move to a 2xD drill and dual contact holder for this but I was hoping to space out the new tool purchases (to utilize the TSC) over the next few months to soften the hit on the budget.

Anything I'm not seeing here? I have some drops from previous lots of raw stock that I guess I could compare for squareness. Any other ideas?

I simply cannot afford to have a part lift on this drill - I know it would completely wreck my spindle. Worst case I can go to punching a through hole with a smaller drill and roughing with another tool (helical boring).

Harmonics can be finicky, a few things I would try.
-Only break through as far as needed.
-Hand code the drill to reduce RPM before retract, IF there is any benefit to using the TSC, higher feeds or insert life (Larger coolant ports don't require as much pressure).
-Stabilize the middle of the part with a rest where it spans the vises and up the feed if possible.
-Try a shorter drill with a dedicated insert for center and periphery cutting.
-It is aluminum and RPM is forgiving, try increasing or decreasing the speed slightly. (Sometimes a few RPM is a big difference in breaking up the chatter wavelength.)
 
It is 1000psig. I've got some relays laying here to get the low pressure hooked up (basically uses the feed pump through the filters into the spindle and bypasses the high pressure pump) but I need to do some electrical voodoo because of how Okuma spare M code keep relays work. The coolant ports face down the Z axis so upon breakthrough they are pointed towards the table. Maybe chips are blasting back upwards or dislodging from the T Slots and getting in the way?

I don't have a square but the machine cuts square (I check parts on my CMM) and I did just check tram by sweeping the vise bases at the one year mark and everything looked good.

I tried feeds of 0.006-0.010" and it wouldn't break a chip.

When the tool rep gets in I want to try feeding in and out and lowering the breakthrough amount. I may also try a boring cycle and just stop the drill at the bottom and feed it out.

Then again I might find out the last guy had the wrong inserts in there and that's been a problem the whole time LOL.
 
I'm wondering if you have steel inserts with edge prep instead of aluminum inserts, and the material is building up on the edge of the drill or insert which catches on the retract. The description of rough finish, oversize hole and limited feed rate supports that suspicion.
Can you post pictures of the drill and the workpiece?
 
Make the jaws so they go over the top of the stock so it can’t lift out. You will have to open the jaws a little wider to switch parts.
Don


Sent from my iPhone using Tapatalk Pro
 
Make the jaws so they go over the top of the stock so it can’t lift out. You will have to open the jaws a little wider to switch parts.
Don


Sent from my iPhone using Tapatalk Pro

I can't the parts get 100% OD profiled. That's one for me to file away for plate work, though!
 








 
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