Shallow depth of cut.. ???

[Eddieweeks]

Just an update.... .. All chattering quit after 4-6 parts.. Just finished all parts.
Now its just a nice hummmm... Still running 1/2" end mill 700 SFM 0.160 DOC..
Doing sloting and 0.65 x D cutting. I just order 3 brand new stuby tool holders 1",3/4",1/2".. I want to thank every one for there help... Save me a lot of
time..

Eddie Weeks
http://www.corpcomp.com/weeks1/

[ctate2000]

350 SFM for standard carbide emill in 1018 is too fast. Four flute in slot is wrong tool. The chatter may be from combination. Try 150sfm and no more than 3 flutes for full engagement.

The fact that you can run indexable and get good results tells me the machine is probably ok. The forces exerted by indexables are greater than from standard emills.

[Eddieweeks]

After talking to my good friend (machine shop owner), He said that 700 SFM was
really fast. I reminded him that Justin (Tool salesman) said if you wear or damage
this tool do this job, I will give you another one free. He was right. I finished the
job and it was fine. Tool guy it has some supercoating and the 4 flutes were
at odd angles not 90,180 ect... Also he said turn off the coolent, and I did.. ???
The part was large and the cuts were small so the part never got hot.

ctate2000... can you explain "that you can run indexable"

Thanks
Eddie Weeks

[Neal]

Do you have a locking drawbar or non-locking drawbar? The difference is 1650 to 2011 psi fopr the locking and 800 to 1000 psi for the non-locking in retention force. Also the bellville stack should be checked to insure that the correct retention pressure is there.
Next would be to look at the tool diameter vs tool length to get the best stability available.
Just food for thought.

Neal

[ctate2000]

Indexable tools are also known as "inserted". I suppose either term is correct. I used to run the family shop and recently left to take position as Mfg Eng. We had three Fadals two 15xt (now 3016L) and one 4020A. I could take heavier cuts on the small machines than on the larger one. Never figured out why. Probably the compactness of the 15xt. They are good machines and I never once had any complaints about them. We used to mill some 303 SS impellars from solid bar. They were 3.5 to 4.0 in dia 1.25 long and had 5 veins. The tool was a carboloy micro turbo mill single flute indexable with .125 R on the corner. Cutting speed was 6500 rpm and feed rate was 35 ipm. Radial depth of cut was full engagement and axial depth of cut was .0625. Took 15 mins to mill one complete and I got three parts per cutting edge. The reason it works is because the radius on the corner was half the axial DOC and it was like using a full round tool.Chip thinning due to radius allows you up the feed rate to maintain proper chip thickness. I would highly recommend the micro turbo mill for your machine. They are very free cutting and perform well in all materials.

[Richard C]

Your chatter may be a result of the spindle bearings not having sufficient preload.
If the cutter chatters more in the morning (when the spindle is cold) than at the end of the day (when the spindle is warm) that is an indication of a bearing preload problem. If it chatters LESS with the spindle chiller OFF then it is a preload problem as the spindle will be warmer than spindle housing and the spindle will expand and increase preload on the bearings.

You can check the spindle for axial freeplay (in the Z direction) to determine if the spindle bearings have lost their preload. Place a dial indicator base on the spindle housing (not on the table) with the indicator on the spindle nose. Use a bar pivoting on a block to provide an upward force to load the spindle bearings. Use a block of wood on the spindle nose. Don't overdo it with force on the bar, as you should see a deflection with a couple hundred pounds of force on the spindle. You should not see even a .0001 of axial movement in the spindle.

[dango]

Originally Posted by Richard C . You should not see even a .0001 of axial movement in the spindle.

I have to clear somthing
in about 1000 PSI you should read 0.02mm to 0.04 mm this for 10K spindle
for 15K spindle it 0.05 mm
to calculate 0.02mm it about 0.0008

[Richard C]

Do you mean 1000 pounds of force? That is a lot of force for a shop guy to exert on the nose of a spindle without force measurment and a means of insuring that the Z axis ball screw brake is not damaged.

If you are using a force/deflection method of setting spindle bearing preload, the total tolerance on bearing deflection (at about 1000 lbf.) should be around .00005 inch or 1.5 micron. The range of deflection values between .02mm and .04mm (.0008 inch) is an ENORMOUS variation in preload.

[dango]

Sorry I mean 1000 lbf but if you will have spindle that the preload is 1.5 micron
It will not turn by the hand and not sure that it can turn by the motor I will try to post here Fadal paper that talk about it

[Verfur]

Eddie,

does it chatter in bouth the X and Y direction.If not then try a convenional cut vrs. climb on the axis that chatters see if that changes much.

Have you check the lash in the ball srcews and or the thrust bearings?

what size it the spindle tapper? From here it looks to be a 30.


Just thought I would ask
John

[tomsin22]

Try using a shorter style hard body tool holder. Also try using a rougher endmill and then come back though with a three flute finishing mill.

[Eddieweeks]

Originally Posted by tomsin22 Try using a shorter style hard body tool holder. Also try using a rougher endmill and then come back though with a three flute finishing mill.

That is what I did.. And I have not had any chatter. It seems the problem
was in the tool holder the whole time. I have also changed to stubby endmills
when I can (Hanita) and have been cutting alot of material.

Eddie Weeks