Shallow depth of cut.. ???

[Eddieweeks]

A month a go I received a remanufacturing VMC 3016L and everything is fine
untill I got a job to cut 1018 steel. No problem right..

I wrote the program for a .319 depth of cut with a 3/4" 4 flt carbide endmill
and it chatter bad. Changed to .150 DOC.. Chattered... Moved all
the way to 0.043" DOC before it quit chattering... I am running 350 SFM
and 0.0015" per tooth.. Even at 0.043 DOC if I changed the RPMs it will
start chattering.

Put a brand new Kenametal 1" end mill with 2 flt inserts and ran 1000 SFM 0.006 per tooth, no problem but only could cut 0.050 DOC..

The tool saleman cam buy yesterday and put in a 1/2 4 flt super end mill
700 SFM.. 0.319 DOC and it cut, but chatterd at a very high frequency..
I changed it to 0.160 DOC (or 2 passes)... It cut ok.. still chattering..

Am I expecting to much from this machine.. ?..

I am cutting 1018 steel, 2.5 sqare bar sitting in the bottom a 6" kurt vise

Thanks for you help...

[carbidecraters]

Sounds like the spindle bore may need to be ground. It could be also your tool is sticking out of the holder too far. Generally though you should be able to take 3/4 of the diameter of the tool without any chatter. Was it sqeaking as well? Is it in format 2? I could write a small program that would test the chatter

[Ken_Shea]

Ther are many variables but here are a few things to consider from Niagra tool Cutter. They have extensive technical information.
http://www.niagaracutter.com/

Feed and speed too fast
Lack of rigidity (machine & holder)
Poor set up
Cut is too heavy
Overhang of tool is too much
Lack of relief
Decrease relief angle, make margin: (touch primary with oil stone)


Here is another very useful link for software that offers speeds and feeds and bunches of other useful machining, drilling, tapping information.
http://www.mrainey.freeservers.com/


Ken

[carbidecraters]

Reman'ed from Fadal means very little these days. Insiders say that they dont check all the things they say and they just once over and ship the machine.....its a sham!!

[carbidecraters]

Originally Posted by Ken_Shea Ther are many variables but here are a few things to consider from Niagra tool Cutter. They have extensive technical information. http://www.niagaracutter.com/ Feed and speed too fast Lack of rigidity (machine & holder) Poor set up Cut is too heavy Overhang of tool is too much Lack of relief Decrease relief angle, make margin: (touch primary with oil stone) Here is another very useful link for software that offers speeds and feeds and bunches of other useful machining, drilling, tapping information. http://www.mrainey.freeservers.com/ Ken

Ken it seems like even the tool salesman couldnt get it right...hmmmm

[Eddieweeks]

It is difficult to describe the sound... you know when it drills, it makes
no sound.. When its cutting well. All I hear is a nice humm.. I am not sure
I heard sqeaking, each tool chattered / squalled differently. The 1" made
the most racket.. The 1/2 at 700 SFM was very high pitch and left a chattering finish.. We ran the 1/2" at 10 to 70 ipm and only the inensity
changed.

i am going to test the spindle bore with a blue marker..

Thanks

Originally Posted by carbidecraters Sounds like the spindle bore may need to be ground. It could be also your tool is sticking out of the holder too far. Generally though you should be able to take 3/4 of the diameter of the tool without any chatter. Was it sqeaking as well? Is it in format 2? I could write a small program that would test the chatter

[HuFlungDung]

If the toolholder is good, and the spindle taper is good, you might have broken springs in the tool retension rod. When the tool gets enough bite on the work, the helix of the flute is able to pull the toolholder out of the spindle a wee bit. This would be visible after some extended period of time as a brown rust stain on the tool holder shank, called fretting corrosion.

[carbidecraters]

Originally Posted by HuFlungDung If the toolholder is good, and the spindle taper is good, you might have broken springs in the tool retension rod. When the tool gets enough bite on the work, the helix of the flute is able to pull the toolholder out of the spindle a wee bit. This would be visible after some extended period of time as a brown rust stain on the tool holder shank, called fretting corrosion.

yup yup yup

[Eddieweeks]

Does everyone agree, that this machine should be able to cut more than
0.050" with a 3/4 endmill.. I would be happy with 0.200" but 0.050" is unacceptable.

I will check on the spring. Thanks

Eddie

[HuFlungDung]

I vote, yes it should be able to cut .2" deep with a 3/4" endmill. I will qualify that statement by saying that a solid carbide endmill may want to scream a bit when its brand new, if the edges are really keen. A tad too much clearance is responsible, but usually after a break in period this noise will diminish.

An inserted tooth endmill, with typical honed inserts should behave itself right from the beginning.

[Geof]

I am not familiar with this machine but I have had chatter problems on big manual machines because the spindle bearing preload was not high enough. If the machine has been remanufactured this may be something to check.

[carbidecraters]

We run .75 endmills .310 deep at 200sfm in lasered edge 1018 all day with a little 3016 but the linear ways are something we dont have.