[fozzyber]

I have 2 issues I hope some one can help with, I have gotten my machine up and moving. (YEAH)
I can jog the Y at about 230in/min. but I can only jog at about 110in/min on the X, what the heck I was expecting some where around 180in/min.
Problem 2: I have my gibs and thrust bearing set snug but not overly tight, but I have about .005 - .006 in backlash this seems a bit high for a ball screw machine. Can anyone point me with where to start??


Machine specs:
-G0704
-power supply 48 v 12.5 amps.
-MX3660 controler
-570 in oz steppers
-C7 ball screws -stock thrust bearings


Thanks

Jerry

[rs4race]

it sounds like we have pretty much the same setup and i got up over 300ipm x and y. Did you lube up your bearings well? How tight are the preload on them? Are the ballscrews aligned well? Settings on the mx3660? In mach3?

On my z axis I originally got 120ipm with low accel and it would stall near the top. I didnt have to bearing greased well and the top plate wasnt aligned. I regreased the bearing and then aligned the plate. I was able to set speed up to 145ipm and accel up too. I had other issues i noticed during assembly such as the bearing pockets on the new parts not being round. It caused the bearings to bind.

Also are you setting your jog speed to the rapid speed or using shift plus arrows?

Im still a rookie here but I just got my machine together and had it running a few hours lastnight cutting out a part. Hope this helps.

[rs4race]

Oh and i cant say much for where to start with the backlash but that is pretty high. The backlash on my stock screws was between .003-.004" depending on axis. Now it is less than .001" for each, its hard for me to measure though since thats the finest graduation on my dial indicator.

[Fastest1]

Same steppers on X and Y? Same microstepping value? Have you tried swapping the axis on the MX3660 and see if it is electronic in nature? I am guessing the ballscrews are the same, most likely a 1605. Worth a try before tearing anything down.

In all honesty the backlash isnt too far off. Some of us get very low readings at first (many dont) only to find after a few hours of machining time, larger amounts of play become the norm. .005-.006 backlash isnt terrible and a thorough going over of all fasteners and motion assemblies could likely reduce it a thou or 2.

[fozzyber]

I think I might have found an issue, it seams that when I ordered the ball screws the X nut was ground down, but not far enough, it looks like it might be rubbing the bottom of the table. I pul it down tonight and have a closer look.

How do I pack these c7 ball nut with grease? as rs4r says?

[Fastest1]

It has a Zerks fitting on the ball nut. That being said most use oil. Personally I use a Q Tip and manually lube the ways and screw with Hangsterfers Way oil. If I was production maybe I would change my methods.

[fozzyber]

no zerks on mine???? I got them form automation technologies


jerry

[Fastest1]

They usually come in a bag uninstalled. If you look around the edge of the ball nut flange, you will see a small threaded hole(not the set screw hole for the wiper ring). That is for the Zerks.

[fozzyber]

pulled the table off, and removed a bit off the ballnut readjusted , now rapids at 175 in/min at 30 acc. much better now..

I will have to look for that zert....

[arizonavideo]

That does seam a little hi for backlash.

Is the mill new, you do need to run in the ways a bit so they smooth out. It really should be the end support bearings because I dont think you could get .006" out of the C7 screws ever.

I just did a test of my G0704 that I put a kit on and had less than .0006" on the X and Y and that is with Roton screws. I still get 200 and 350 IPM speeds.

I did a quick video of the test setup.

Grizzly G0704 CNC kit Roton ballscrews backlash test - YouTube

[rs4race]

I didnt grease my ballnuts. I am using oil on the ballscrews/ballnuts. I was refering to the thrust bearings for grease.

[Fastest1]

.0006 is pretty rare. I have not seen anyone with that low of numbers on a G0704. Nice.