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Posted by Stan Dornfeld on August 10, 2006, 8:52 pm
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Hi Gang..
I was cutting a square about 4" on a side 6061-T6 aluminum. 5/8 three
flute, in my KMB-1. Depth of cut .060 ~
I finally raised the rpm and it settled down.
Just wondering what the cause is. I need some bearings in the head; but I
don't know if the precision spindle bearings are the problem.. The mild
noise may be from other bearings.
Any ideas appreciated.
Best regards,
Stan-
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Posted by Anthony on August 10, 2006, 8:53 pm
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> Hi Gang..
>
> I was cutting a square about 4" on a side 6061-T6 aluminum. 5/8 three
> flute, in my KMB-1. Depth of cut .060 ~
> I finally raised the rpm and it settled down.
> Just wondering what the cause is. I need some bearings in the head;
> but I don't know if the precision spindle bearings are the problem..
> The mild noise may be from other bearings.
>
Climb or conventional?
--
Anthony
You can't 'idiot proof' anything....every time you try, they just make
better idiots.
Remove sp to reply via email
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Posted by BottleBob on August 10, 2006, 9:04 pm
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Stan Dornfeld wrote:
>
> Hi Gang..
>
> I was cutting a square about 4" on a side 6061-T6 aluminum. 5/8 three
> flute, in my KMB-1. Depth of cut .060 ~
> I finally raised the rpm and it settled down.
> Just wondering what the cause is. I need some bearings in the head; but I
> don't know if the precision spindle bearings are the problem.. The mild
> noise may be from other bearings.
Stan:
I doubt that it's anything spindle related, since spindle related
chatter would probably affect both axes equally.
We just had a similar thing (bad finish in Y, but fine in X), happen in
one of our Fadals. We have a service (Ex-Fadal techs), come out
periodically to do maintenance on the machines. I believe it was a
gibbs adjustment issue in our case.
--
BottleBob
http://home.earthlink.net/~bottlbob
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Posted by Duffy on August 10, 2006, 11:40 pm
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>
>
> Stan Dornfeld wrote:
>>
>> Hi Gang..
>>
>> I was cutting a square about 4" on a side 6061-T6 aluminum. 5/8 three
>> flute, in my KMB-1. Depth of cut .060 ~
>> I finally raised the rpm and it settled down.
>> Just wondering what the cause is. I need some bearings in the head; but
>> I
>> don't know if the precision spindle bearings are the problem.. The mild
>> noise may be from other bearings.
>
> Stan:
>
> I doubt that it's anything spindle related, since spindle related
> chatter would probably affect both axes equally.
> We just had a similar thing (bad finish in Y, but fine in X), happen in
> one of our Fadals. We have a service (Ex-Fadal techs), come out
> periodically to do maintenance on the machines. I believe it was a
> gibbs adjustment issue in our case.
>
> --
> BottleBob
> http://home.earthlink.net/~bottlbob
Stan,
Dittos on the gibb adjustment. I had a similar problem on a bridgeport not
long ago. Lousy finish in one axis. It took a little playing around with the
adjustment to get the finish back to normal. I took a test cut after each
adjusment to see what it looked like and was amased at the variety of
finishes you can get when the gibb is off adjustment. Everything from
herring bone to diamond.
Good luck
Duffy
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Posted by F. George McDuffee on August 10, 2006, 11:18 pm
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On Fri, 11 Aug 2006 00:52:36 GMT, "Stan Dornfeld"
>Hi Gang..
>
>I was cutting a square about 4" on a side 6061-T6 aluminum. 5/8 three
>flute, in my KMB-1. Depth of cut .060 ~
>I finally raised the rpm and it settled down.
>Just wondering what the cause is. I need some bearings in the head; but I
>don't know if the precision spindle bearings are the problem.. The mild
>noise may be from other bearings.
>
>Any ideas appreciated.
>
>Best regards,
>
>Stan-
========================
This *MAY* not be a cnc/spindle bearing problem at all. All
mechanical systems have resonance points, and modes, that is
frequencies and directions. As you change jobs and fixtures your
resonance frequencies and modes will change.
The manufacturers go to great lengths to eliminate resonances in
the normal operating ranges, but with time and wear...
Try bolting a heavy piece of steel to a corner of your table to
see if what (if anything) changes. If you have lighter and
heavier tool holders to fit the end mill try changing these.
If the chatter frequency / mode-axis changes, you may have
another problem.
Cheap and easy to check before starting to replace parts [one
after another]
I like BottleBob's suggestion to check the gib adjustments. How
hard are these to get to / adjust on your machine? Any special
tools required? When was the last time these were adjusted?
Unka George
(George McDuffee)
...and at the end of the fight is a tombstone white
with the name of the late deceased, and
the epitaph drear:
“A Fool lies here, who tried to hustle the East.”
Rudyard Kipling The Naulahka, ch. 5, heading (1892).
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>
> I was cutting a square about 4" on a side 6061-T6 aluminum. 5/8 three
> flute, in my KMB-1. Depth of cut .060 ~
> I finally raised the rpm and it settled down.
> Just wondering what the cause is. I need some bearings in the head;
> but I don't know if the precision spindle bearings are the problem..
> The mild noise may be from other bearings.
>