Need Help!- X-axis speed question, photos attached

[Phattie]

Howdy guys...long time reader, first time poster I'm still fairly novice, perhaps this is a really easy question:

I've got a couple small carving machines built for specific purposes. One of them was the "built from cheap & leftover parts" style, and the axis were constantly having trouble, etc. Long story short, got the idea to replace them both with K2 axis bolted together, figured this would be a nice, fast, easy, and rigid solution. As pictured below, the sideways axis is considered the Z, and the vertical axis is considered the X. Since bolting these together, I cannot get more than 30 inches of speed out of the X. If I go so much as 35, regardless of the acceleration, it will jump out of place after about an hour of running. The old ghetto-fab axis with the same motor mounted on it did around 70. This is only critical because it takes roughly 12 hours to complete a carving. Now that it's not working above 30, the carving time is over 24 hours...which doesn't really work out as I won't leave it running all night unattended.

I've tried a bunch of different things, and I'm 99.9% sure the motor, board, and software are all just fine. None of that has changed, only the axis were replaced. I did put a dab of grease on the lead screw which helped for about an hour, made it noticeably smoother for a while, then it jumped out of place and slowed down (having searched, I now see this was probably wrong, and I'm pulling it apart to clean all the grease out this morning).

Anyway, point is: Do you think I should be able to run the pre-assembled axis with a feedrate above 60? Or perhaps since the axis is designed to be used as a Z (not an X like i'm using it for), is about 30 where it's going to top out? I'd love to be able to sort this out as soon as I get all the grease off of it...thanks in advance for any help, down-time sucks!

[ger21]

What motor, screws, drive, and voltage are you using?

[Phattie]

The x-axis motor is a 640oz 5.5 amp, the boards are all Gecko G202, and the lead screws pitch is .1, 10 revs per 1", kerk nut with anti backlash feature. The power supply was replaced about 6 months ago as well, with a pretty nice one, borderline overkill but within the G202 specs, definitely not a lack of power in that department. Let me know what other info might be helpful-

[ger21]

Voltage, and motors inductance if you have it.

[Phattie]

Can't find anything on the motor itself, but according to the invoice it's 2.3 volts, and the Induction (mH) (+/- 20% typical) is 3.5.

[ger21]

I meant power supply voltage, sorry.

I'd expect a max of 60-100ipm, with the proper voltage. If the voltage is too low, it could cause what you're seeing. I'd also check for any binding. You should be able to easily turn the screw with your fingers through the entire range of travel.

[Phattie]

No problem! The power supply is 48v w/10 amps. The Z could be turned by hand a couple days ago, but currently after greasing it it's too stiff. Cleaning all that off now and going to fire it back up...a feedrate of 60 would be great if it'll stop skippin' around. Thanks for the help-

[ger21]

Try a light oil. I use pneumatic tool oil on my screws.