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Offline spunk

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Fast sherline
« on: February 21, 2010, 03:19:20 PM »
Hey guys

will post some pics and vids when i get to it...
have installed 45W servos on the sherline mill at home

now, this makes things go fast (like i hoped  ;) )

problem now is the leadscrews flying around like crazy... any ideas? has this been solved before?
have some ideas but thought i'd hear you guys out at first...

cheers

Philip
Re: Fast sherline
« Reply #1 on: May 17, 2010, 02:15:39 AM »
for the x you can use a nylon cable clamp, they look like a P when viewed from the side. the y would work too but you will lose .375 at full y-0. I've am just getting an a2z conversion going with standard metric pitch and thats what they put there. The backlash nuts don't like much more the 40imp though.

Offline RICH

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Re: Fast sherline
« Reply #2 on: May 17, 2010, 07:27:06 AM »
 Idealy the lead screw should have screw support at both ends. The other option would be to make a bracket which would
provide a quide at the un anchored end to keep the screw from whipping around. There are a number of combinations of
 how to support the screw. You will find sound information on the subject in many of the ball screw manufactures info
such as Nook, NSK, etc. Have a look at what they recomend as far a distance between supports as compared to screw
diameter.
The brass nuts on the screws wear rather quickly if you run the axes at high speed. By wear i am meaning backlash.
 So the anti backlash nut adjustment setting won't last very long. You can improve that somewhat by making a longer nut or two instead of one.
Note that you require an odd ball tap / not cheap ( don't ya love they way they  design things in like that).

RICH

Offline spunk

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Re: Fast sherline
« Reply #3 on: May 17, 2010, 07:45:29 AM »
backlash is a bitch!

even when i'm machining ALU at a speed of 200 mm/min with a step depth of 5mm and a stepover of 0.5mm (10mm flatendmill) you will see a significant difference between the different steps you take...

anyway, will need to make a more solid machine to put the servos onto with ballscrews and the whole lot...

will try to put something together to keep the leadscrews from trashing themselves and the crossslide.

Re: Fast Sherline
« Reply #4 on: May 18, 2010, 02:44:05 PM »
Heres a picture of the clamp.

p.s. if the screw is bent straiten it. with servos it hits 1000 rpm shaft speeds no problem w/ 14" of t ravel

Offline RICH

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Re: Fast sherline
« Reply #5 on: May 18, 2010, 03:36:16 PM »
That clamp may restrict the flapping around of the screw some but it's not doing the intended job.
But if your happy what more can i say.  ;)
RICH
Re: Fast sherline
« Reply #6 on: May 18, 2010, 08:00:22 PM »
That clamp may restrict the flapping around of the screw some but it's not doing the intended job.
But if your happy what more can i say.  ;)
RICH

my screw is straight and it does not flap at the max speed of the servos which is a 1000 rpm, I checked :) but i aggre a bearing would be nice