Need Help!- spade drill problems

[stovepipesteve]

running a VF3,
im using an AMCE spade body with an 3.375 insert. drilling 5'' deep. 4 times.
ive used 130 sfm. with .02 fpt. it locked up spindle and had not reached full dia.
i went to 100sfm. with .012fpt. made it bout 1'' in and locked up agian.
Has anyone had experience using large spade drills, i could definatly use some advice.

[dcskid]

DOES YOUR MACHINE HAVE ENOUGH TRUST. DC MOTORS REQUIRE MORE RPM'S TO GET PROPER AMOUNT OF TORQUE. WHAT IS FPT?

[HuFlungDung]

That is a pretty good sized drill, and I don't think that the Haas has enough torque to turn it. What you lose in a machine using a VFD is torque multiplication: not enough gear ranges to get the motor into its rated horsepower/max torque range, and so not enough current can be sent to the motor, even though it demands more (without damaging something).

If using a geared head, in low gear, I think you need to have the spindle turning about 450 rpm to get max torque. Because the drill is such a large diameter, this speed is not possible without burning the corners off the blade.

I suspect you'll need to open the hole with maybe a 1.5" drill, then rough it larger through interpolation. Spade drills don't start too well in a pilot hole.

[WOLOG]

Are you using a TA style or the universal type. These spades are not known for free cutting. Try a Allied Gen 2 if it is available. These cut a lot better. If the machine doesn't have a gearbox, I am not sure if you will make it. All I can say is slow down your feed until your spindle load is around 85% and just deal with the long strings.

[Donkey Hotey]

I didn't see a material listed in there but Haas regularly runs a demo at Westec where they are drilling 3+ inch holes in 1018 steel. They drill through a solid 1" plate, with no pilot hole, in about 30 seconds.

Take a look at this video:
http://haascnc.com/news/new_files/VMC/VF-5-50.wmv

At the 3:00 point, you can watch the drill cycle. This is a 50-taper machine, probably 30 HP and they're running through-spindle coolant, but you get the idea: it is possible. I don't think they changed the drill all day.

You might check with a few cutter manufacturers.

[Mic6]

Ahh yes, the drill that throws chips against the window that sound like baseballs? I love seeing that demo in person.

[MikeOD]

I've been the guy running that demo at the shows before. Pay attention to that though, it's an insert drill, not a spade drill. Spade drills and CNC machines almost never mix well together, double inserted drills are essentially a single insert and they run with a lot less thrust and torque load. I've recently pushed a Kennametal DFT 50mm drill in Titanium 2.5" deep with coolant through the tool and been very impressed by how low the spindle power and z-servo thrust has been to make the hole...very impressive cut and the machine is essentially saying "ask me to do something harder".

[HuFlungDung]

Mike is correct. I suppose not many machinists have ever hand fed an insert drill. I have, on a lathe. The difference is night and day, in thrust pressure required. But the spindle still feels the torque requirement to make the chips regardless of how easy the drill feeds.

Chances are that the 3" insert drill is also running at near the optimum speed range on the motor's torque output curve.

My old VF3 is only 15 hp. It will drill with a 1.5" insert drill, but with difficulty (near max load) because it is running at the high end of low gear range or the low end of high gear range, in either scenario, the torque is off optimum. The spindle motor develops its maximum torque when it is getting the most amps that are allowed. That is only near nameplate rpm: 1750

A 30hp motor would help a lot.

[stovepipesteve]

im the 3.375 spade drill in a VF3.
30 horse, gear driven,thru spindle coolant at 800+psi.
material is A36 steel.
im running in low gear round 125-150 rpm & 1.5-3.0 feed. these are the ranges ive tried to no avail.
AMCE spade drill company claims i should be able to run these ranges like a hot knife thru butter and if i cant,then theres something wrong with machine.
(The machine is less than a year old and still under warranty).
i called Haas,and got the run around with no good answers. They said they would send a tech to talk with me.
Surly someone has ran large spade drills in 30 horse machines. I must get to the bottom of this,im running over quoted time and have tapped out my tooling expense for the job.The shop sunk alot of money into this drill idea.

For now,im drilling a pilot at 1.875 with an OTM insertable drill (does an awesome job at 1730 rpm and 2.75 ipm. drilling 5'' deep).
then rough it to 5.05 ,then finishn to 5.125.using a DAPRA 1.5 ,8'' long, 3 insert end mill, helicial interpolating.
which i was told could get a 63 finish,holding +/-.0015. (5"deep bore).
i am not getting the finish( a whole nother ball game) i need a borehead,aint got one.
any advice would be great,

[HuFlungDung]

One thought is to double check the parameters. Now my Haas is too old to have the parameters on the main screen, so I have to go check them on the spindle drive at the back. But your new machine probably has them up front on the main screen. Anyways, make sure that everything is set as per factory instructions.

Funny thing used to happen on my cnc lathe, where I have a Baldor DC drive on the lathe. Once in a while, the drive would act up and need to be reset a few times before it was ready, something called a base ID fault. This fault used to derate the drive to a much lower horsepower, and the lathe was a gutless pig until the settings were restored.

[WOLOG]

What type of spade are you using? Is it a TA or a universal spade? If it is a universal type, you will not be able to run it in a VF-3. I run a 6" Allied universal spade in a 25" x 120" DS&G Hollow spindle lathe in 4140 HT and the machine draws 60 -70 Amps on the load meter. The machine is a brute and it struggles sometimes. A universal spade is not sharp and it takes way more thrust to cut than a Gen 2 spade. If you can,take a picture of the spade and spade bar. I am curious. My VF-5/50 has problems pushing larger spades. I have seen a VF-6/50 run a 4" OTM inserted drill.

[stovepipesteve]

Originally Posted by dcskid DOES YOUR MACHINE HAVE ENOUGH TRUST. DC MOTORS REQUIRE MORE RPM'S TO GET PROPER AMOUNT OF TORQUE. WHAT IS FPT?

a conclusion has been made.
the VF3, 30 horse,gear driven bad boy cannot run the drill.
A Hass tech. came into the shop and ran some tests.
The Z axis has not got the thrust. bottom line.

thanks to all for the info and tips.