BAD NOISE

D

dodoknives225

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Hey guys so i have a grizzly 8x30 mill before this i have only used my mini taig mill oh and i am not a machinest i am a knifemaker so i don't know a whole lot about these machienes so anyway my grizzly was fine for a while i just used small stuff like 1/2 and below endmills and a slitting saw....so i was attempting something new and had someone guiding me that has done this exact thing before so he recamended a 2in indexable cutter and tpu inserts so i got the exact ones he got....so the problem is when i went to cut the titanium as soon as that cutter hit the titanium BANG BANG BANG....... very loud! so i thought i was cutting to deep but even tring to take passes of .02 it still made this noise. the noise wasn't coming from the work piece to me it sounded like it was coming from the area where the top of the spindle would meet the pully's. does anyone have any ideas what this is and how to fix it i REALLY don't want to break my mill so can anyone out there help any one have any ideas of what it may be or how to fix it? THANKS AHEAD OF TIME!!!
 
Check and see if the belt is OK. Belt separation will cause that noise. The separated section slaps the front of the guard on every rotation.

"Billy G"
 
To provide better guidance, we need a bit more info.......
When you say "but even tring to take passes of .02" what units are we talking? Is that 20 thousands of an inch?
What RPM is your spindle?
Was it manual feed or power feed? and if power feed what is the rate?

Check the gibs. Are your table gibs sloppy? If so, maybe that banging is the table being forced to one side when the cutter meets the work and then returning. If you grab one end of the table and try to move it in X, then Y, then Z, do you feel any slop?

Do you have gib locks? If so, try locking the table in the directions you are NOT feeding.

I hear titanium can be tough to cut. For debug purposes, I would try something less stressful, and work up. Perhaps a depth of cut of 5 thou. on an aluminum work piece, with speed and feed set properly. There are some online calculators for such things......use a couple to cross-check eachother.
If that goes well try 10 thou. depth of cut.

-brino
 
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Pretty sure I know what you're talking about as I had an 8x30 G1004 Grizzly. For me it happened with anything larger than a 5/8" end mill. I adjusted the gibs and locked the knee and table. That helped a lot.
 
I have a Grizzly G1008 mill, same size table 8 x 30. I have 1 1/2in indexible face mill with TPG inserts. I mill mostly aluminium. I do hear each flute hitting the metal when I start. This noise stops once the face mill is over the work.

20 thou in titanium sounds like a deep pass to try out with a 2in dia face mill.
 
Sounds possibly like the splines on the spindle could be rattling in the pulley splines, due to (possibly) not enough of the cutter's teeth engaged in the cut.
 
I have the Jet version of that mill and mine would make a horrible noise under load, kinda like the spindle bearings were going bad. I found that the problem was the center set of pulleys. That set of pulleys can move side to side, to allow the belts to be moved to the different size pulleys. I found that I had to tighten down the bolt that keeps the pulleys from moving or they would rattle like crazy.
 
I also have an 8*30 mill.

Once the work tool gets to a certain size you need to start locking down the movements.
Spindel drop locked,
Bed rise (Z axis) locked,
Bed in/out locked,
Bed traverse is the only movement enabled.

Anytime you are hearing bang, bang, bang, you are essentially hearing the gibs bounce back and forth as the tool applied pressure to the work.
 
DSaul said:
I have the Jet version of that mill and mine would make a horrible noise under load, kinda like the spindle bearings were going bad. I found that the problem was the center set of pulleys. That set of pulleys can move side to side, to allow the belts to be moved to the different size pulleys. I found that I had to tighten down the bolt that keeps the pulleys from moving or they would rattle like crazy.
Click to expand...
That's right. I forgot to add that to my list of things I did to quite it down.
 
Hey guys i got pulled away from the shop for a couple days due to some family issues....but i am back now and i want to thank you ALL i have a few things i have to get done this morning but later today when i get to working with the mill i am going to go down the list of all the sugestions you guys gave....i got a lot of good info from you guys hopefully with all that info i will be able to figure this out....i will let ya guys know how it works for sure THANKS AGAIN!!!
 
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