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Author Topic: Z Axis Counter Weight  (Read 3815 times)

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Offline TDAY

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Z Axis Counter Weight
« on: December 04, 2011, 09:53:01 PM »
Hello all,
 Looking for some advise on where to anchor my counter weight to head assembly. Should it be anchored closer to spindle or closer to linear rails? Ive seen it done both ways on the big VMCs. Wouldnt it be better to have it closer to spindle, to aid in vibration dampening? But, isnt there a possability that a "binding" effect can happen if i anchor out to far? Please look at pics to see what i have designed so far.

Thanks,
Troy
"I try to put forth the effort,before asking a dum question"
http://homecncstuff.elementfx.com

Offline Dan13

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Re: Z Axis Counter Weight
« Reply #1 on: December 05, 2011, 01:38:10 AM »
Troy,

The correct way would be figuring the centre of gravity of the head and anchor it there, I think.

Regarding vibration dampening, this should not be a factor to be considered as the chain cannot transfer any substantial vibrations. The vibrations will be dampened by the head mass and also transferred to the column and base via the linear slides and thus it's important to have well preloaded linear blocks.

Dan

Offline TDAY

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Re: Z Axis Counter Weight
« Reply #2 on: December 05, 2011, 10:25:28 AM »
Troy,

The correct way would be figuring the centre of gravity of the head and anchor it there, I think.

Regarding vibration dampening, this should not be a factor to be considered as the chain cannot transfer any substantial vibrations. The vibrations will be dampened by the head mass and also transferred to the column and base via the linear slides and thus it's important to have well preloaded linear blocks.

Dan
That was my thinking when looking at anchoring closer to the spindle, as the Bridgeport type head and spindle is about 75lbs. As for the linear blocks and rails, when i got them i checked THK website and iam pushin the specs:) Thats the biggest reason iam putting a counter weight on. Take some unneeded stress off of them.

I think i will design counter weight to be "adjustable" , so if needed i can change anchor location. Just dont like Re - Work ;)
Thanks,
Troy
"I try to put forth the effort,before asking a dum question"
http://homecncstuff.elementfx.com