Bit issues? Router shakes on X axis cut only

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Bit issues? Router shakes on X axis cut only

Postby musicalfisherman » Tue Jan 08, 2019 8:32 pm

I run a CNC Shark HD4 with the water cooled spindle. It was purchased and set up by the person I run it for, and I am the only one who has cut parts on it.

The program I am trying to run is a pocket route. It's a 4" x 4" square that is 1/4" deep. I've tried it 0n both MDF and solid maple. I'm running a brand new 1/4" diameter two flute upcut bit by Whiteside.

12,000 rmp
50 inch/minute
30% stepover (.075")
3/32" pass depth (.092")

The problem I'm having is that going left to right on the X axis cut the router will start "shaking" or "bouncing" - like it's trying to cut through too much material and it can't. It only happens on the left to right cut. Y axis cuts are fine, and the right to left on the X axis cuts fine.

My first question is does my speed / rpm / pass depth / step over seem OK. I think I should be able to cut deeper and faster than this. Most of my experience is on a 4 x 10 Weeke Vantage, so I'm not sure if my hopes are just too high for what this machine can cut through.

If my tooling setup seems good, then what might be causing this issue? I find it odd that it only happens in one direction and it makes me think there's something I need to adjust on the machine.

Thanks in advance!!
Daryl
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Re: Bit issues? Router shakes on X axis cut only

Postby WNC_Ed » Wed Jan 09, 2019 11:14 am

Daryl,
I have been running mine (HD4 Extended) with various 1/4" EMs a lot faster and a lot deeper with various materials with no issues.
If you run the program "cutting air" does it shake or bounce going left to right? Or only under load?
Also, has the spindle been "trammed" to the spoil board? I doubt that is the issue since I would think it would be visibly out of whack to cause a vibration - but worth asking the question.
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Re: Bit issues? Router shakes on X axis cut only

Postby musicalfisherman » Wed Jan 09, 2019 11:54 am

Ed,

Thanks for your reply. I have done a dry run on the program and there are no issues with shaking when it is cutting nothing.

I'm not familiar with the expression "trammed" so I can't answer that.

Would you mind sharing an example of a 1/4" end mill...inches / min , stepover and pass depth just for my reference. Like I said I've not no grid for the capabilities of this machine.
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Re: Bit issues? Router shakes on X axis cut only

Postby WNC_Ed » Wed Jan 09, 2019 1:17 pm

Daryl,
I don't have the CNC Laptop with me at the moment - can share later this evening.
Off the top of my head I recently ran a 1/4" Bosch upcut spiral bit at 9,000RPM and 125 IPM with .125 cut depth. through 2" of cypress which granted is a soft wood.
the slab cutout was roughly 18" x 42" and I cut out 5 slabs. The above mentioned was the last slab as I tried tweeking the settings through the other 4. I am confident I could have been more aggressive but was fine with the time. Thinking the initial settings for the first slab were not to far off from yours, I dialed the RPMs back and increased the IPM because the bit was screaming at 12,000RPM and 100 IPM. Somewhere a wise man suggested that a screaming bit was a hungry bit so increased the IPM and decrease the RPMs. It helped.

The "Tram" question is basically 'is your bit perpendicular to the bed or spoil board.

Not sure I am helping but sounds like maybe something loose in the "X" axis drive?
I can peek at mine tonight and see what can loosen.
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Re: Bit issues? Router shakes on X axis cut only

Postby musicalfisherman » Wed Jan 09, 2019 2:02 pm

Ed,

You are helping very much actually. I now know that the machine is capable of cutting more material at faster speeds. That means my issue is not with my bit or tooling setup.

When I hit pause while running the program the router base would continue to vibrate for 3-4 seconds after the machine was stopped. So I decided to put my hand on the dust collection boot base and apply some pressure while the program was running, and the program ran just fine. Something is loose or out of alignment somewhere.

I was not the one who set up the machine, and have only run a few test parts through it. I'm going to go back through the machine following the setup instructions and make sure everything is correctly assembled / leveled / tightened.

I really appreciate your feedback! It's pointed me in the right direction.

Daryl
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Re: Bit issues? Router shakes on X axis cut only

Postby WNC_Ed » Wed Jan 09, 2019 7:29 pm

Daryl,
I suspect your "X Worm nut" or whatever the technical name is might be loose.
That would explain why it shakes going right but not left.
Going left it is being pushed up against the bulkhead so no slop
Going right it is being pulled away from the bulkhead and if loose would cause binding.
Hope this helps.
Ed
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Re: Bit issues? Router shakes on X axis cut only

Postby musicalfisherman » Thu Jan 10, 2019 1:51 pm

Ed,

The X worm nut was indeed loose, and the bit was not leveled with the table.

I decided to go through the entire top part of the machine. I pulled the router, removed the router mounting base, and tightened every nut I could find. And almost all of them were loose. I also decided to move the gantry to it's lowest position (it was mounted at its highest). Once everything was tightened and back in place the bit was running perpendicular with the table.

Everything is running great now! No shaking or bouncing to speak of and I can cut at much higher speeds than before.

Thanks so much for taking the time to help me on this!!

Daryl
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Re: Bit issues? Router shakes on X axis cut only

Postby WNC_Ed » Thu Jan 10, 2019 4:39 pm

Daryl,
Awesome! Congrats.
Now you can make some wood chips.
Happy I could help.
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