[fpm06001]

Hello,

I recently purchased a used g0704 mill that has a cnc conversion and have been experiencing some problems with it.

2 of my stepper motors are damaged (x and y mounting flange is cracked,one of the 4 bosses is missing), the previous owner has been running it like this for a while, however i want to fix it by purchasing new stepper motors.

i attempted to mill a circle pocket, and ended up with an egg shaped circle ,i went in and checked/reset the backlash in mach3 and came up with a less of an egg shaped circle (the main reason i want to replace/fix the stepper motor mounts). i am unable to find any markings on the motors and am unsure what i should purchase. i think that they are nema 23 motors shaft measures ~0.31".




stepper motor drivers- from looking at the p/n

x/y--
CNC Microstepping Driver Step Stepper Motor Driver 2M542 4.2A Controller - Electric Motor Controls - Amazon.com

z -kl-11080
http://www.automationtechnologiesinc...-stepper-drive


another problem that i am experiencing is that sometimes if i jog the x and y simultaneously it hangs up and makes this awful noise (table stops moving)

i have attached some photos of the electronics/drivers that i have, and was wondering if there are any "better/cost effective" upgrades, or if i should just replace the steppers and call it a day. once i get these issues sorted out i plan on upgrading the spindle motor (currentrly eyeballing the 2.2kw bldc since i do not have a 220v plug where the machine is currently sitting), extend the y axis, and do a belt drive conversion.

any help in sourcing the correct replacement stepper motors/drivers would be much appreciated.

[CL_MotoTech]

It looks like you have everything you need in there.

If you are still getting egg shaped circles then either you either need to tune your steps per unit, backlash remains in issue, or both. Check all of the mechanicals first. For example I chased backlash on my X axis for far too long once before realizing that the bolts that pinch the ballscrew to the carriage were loose. Amateur hour move, but these types of things aren't all that uncommon. Check your thrust bearings for play as well. Inconsistent backlash measurements are a good indicator of something lose or warn. It's also worth nothing that poor setup of the steps per unit can also produce bad backlash setup.

Finally, if your table is hanging you need to adjust your jibs and lube the ways. They may also need cleaned. My Z likes to hang at high velocities right near the top of travel, but with some adjustment I have managed to get rid of it. I also try to home regularly as to make sure to use the top parts of the travel as often as possible which should in some small way help with uneven wear across the range of motion.

[fpm06001]

Thanks for the response, i will be ordering replacement stepper motors as soon as i can find/figure out what i have (to replace the damaged ones), then checking everything once i replace them. I know that the x and y use a nema 23 frame stepper motor. I was wondering if someone would be able to recommend replacement motors for me (with my drivers). i believe the shaft OD is 8mm (i measured something like .31" on mine)

so im thinking a 428oz nema23 4.2a 8mm shaft?


thanks

[charliex]

i had a hard time getting round circles with lead screws, went double nut ballscrews, but there is round and there is round.

these are decent
STR8 | Applied Motion
Browse Stepper Motors | Applied Motion


the ones you have look fine though. just new motors

[fpm06001]

my machine supposedly has roton ball screws. i will be taking it apart and taking pictures once i order/receive my new stepper motors, so far the only place ive been able to find 8mm shaft nema23 is flebay

i had a hard time getting round circles with lead screws, went double nut ballscrews, but there is round and there is round.

these are decent
STR8 | Applied Motion
Browse Stepper Motors | Applied Motion


the ones you have look fine though. just new motors

[charliex]

should be able to change the couplers to a more common size motor shaft.

[fpm06001]

slight update.

purchased new stepper motors, and just for laughs when i had the old ones disconnected from the ball screws i tried to see if i can get the machine to hang... when i first jog the y then the x... no issues/noises, however if i first start jogging the x axis and then try and jog the y the stepper motors stop moving and make this awful screeching noise, any idea on what that may be?

also, i don't really like the way the steppers are mounted... and was wondering if there is a better alternative? or if they are fine the way they are...


after talking to ben on from instagram i went ahead and ordered a 3ph 1.5hp motor and a vid and will be adding it in the near future.

"to do list"
make 1.5 hp motor mounts
make/buy belt drive conversion parts
wire vfd
extend the base and head for more y travel
install some sort of oiling system/modify machine
model/make a better chip tray/ enclosure using the stock stand as a base, or not (is there a good solid model out there of the machine?)
install high speed bearings
install proximity home/limit switches

[fpm06001]

[Fastest1]

The screeching is called stalling. I will bet the DRO's are showing movement but the steppers are frozen during that sound. Experiment with the accel values and possibly velocity if you have it set at high numbers for the machine.

[fpm06001]

The screeching is called stalling. I will bet the DRO's are showing movement but the steppers are frozen during that sound. Experiment with the accel values and possibly velocity if you have it set at high numbers for the machine.

was poking around in mach/the internet and saw that some people where experiencing the same problem (had to do with the acceleration values as you have suggested), i will be going through it and also removing any bloatware from the computer i'm using.

i will report back when i have the machine back together/up and running. so that i can cut my motor mount bracket

[arizonavideo]

If the Roton nuts were not re packed then they will have lots of backlash.

I think the steppers are 425oz 4A units. If they are then they have fairly high inductance so if you want better high end speed you might want to go to a higher voltage PS if the drivers are made for it. I think the drivers might be 80 V and if the PS is 48 you should go to 65 or 70V.

I have no idea why the guy put the bolts in from the other side of the stepper mounts. Strange way and its not easier.

[fpm06001]

me neither,

i am going to switch out the standoff/bolt situation. thinking of using threaded standoffs cut to size, i also went ahead and ordered some "oldham" coupling , to replace the lovejoy ones.

i will investigate which power supply i have and report back

[109jb]

The drivers are 2m542 drivers, so are 50V max, 4.2A drivers

[coherent]

As others have said, slow down your accel and even your speed and work up till you loose steps and then back it off a bit. I've got the same mill and you'll be happier with the oldham couplers as far as eliminating some backlash. I made my own using 1" aluminum round for the hubs and 1" delrin for the discs. Pretty easy to make. I sized mine after the same dimensions as the ones at McMaster Carr. When I switched from the same lovejoy couplers you show to the oldhams they were much shorter so check your motor standoff distance since the overall length of the oldham couplers may be shorter you may require shorter standoffs.