Problem- motors & axis board?

[mad_dog096]

i am building a cnc router and i am in a jam.

it has on it:

power supply
24v/8.3A

3 axis driver board (megatronics)

THK rails:
thk SR25W
thk SR15V

80/20 frame work

cutting table size
30x37

nema 23 276oz-in (1/4 shaft)

what is going on is that when i move the axis's the motor will skip, both x and y axis's. what i was wanting to know is what can i do to fix this.
what is a good size motor and driver board for compensating for this problem.
any advise is welcome

thx for your time.

[LaserImage]

I had almost the exact same setup except my steppers are 283oz I think. I had problems from day 1 and the only solution was to reduce the speed to about 30 ipm. Even then I still had troubles with losing steps on the Y axis - no other axis, just the Y. I ended up buying a G540 and not only did all of my problems go away, it increased in speed from 30 to 130. Get rid of that Mechatronics POS and get a Gecko - you won't regret it!

Oh, and I am still using the 24v PS - on Mariss's recommendation I tried it instead of the 48v I purchased.

Gary

[CarveOne]

If you are talking about stalling (makes loud noises and doesn't move) consistently in the same place, or places, then you may have binding at those points. I've had plenty of problems with that and have finally resolved them. I still only get reliable 48ipm jogs on the y and x although the z can go 70ipm. With a z axis travel of only 4 1/2" travel that's kinda scary.

Lead screw, rails, and motor shaft alignments need to be thoroughly trued before the binding will go away. A moving gantry must be 90 degrees to the x axis rails at both ends of the gantry.

CarveOne

[mad_dog096]

so what is a good motor size to go with and where do you get the axis board as well.

i bought my acme screws from a guy on ebay and they arrived in not the best of shapes. it does have some bending to it and i do think it is binding, you can spin the screw by hand and you feel some of the hard spots but it sill spins relatively easy.

i will try to relign everything again.

i think what i will have to do is just get a powerful enough motor and axis board to power through them.

thx guys for your help and look forward to hearing where to get the board and whats a good size motor.
thx

[CarveOne]

The most popular range of stepper motors for medium size cnc routers is 270 to 380 oz/in.

I doubt that you will get acceptable results with larger motors trying to overpower an existing binding problem. It will only be an unnecessarily frustrating attempt to salvage bad parts. Replace, or attempt to straighten, the bent lead screws and then systematically align everything so that there is no binding.

CarveOne

[mad_dog096]

we straightened them out the best that we can, i just might have to order some from enco or something,

so on the gecko drive. what one is a good one to go with that has plenty of power and has a lot of accessories to it.

and thx again for all your help.

[LaserImage]

I have a G540 with my Keling steppers and a 24v power supply. The 540 is plug-and-play - you only need to solder your stepper wires to the db9 connectors and plug in your parallel cable. It has everything built in. It's not cheap, but you get what you pay for! Oh, and you even get the xml file for Mach so you only have to calibrate, no other setup needed.

Gary

[mad_dog096]

wow thats great news. ya its lots of money. will have to see.

was thinking of keeping my 24v8.3A powersupply and grabbing the 495 or 425 nema 23 motors from keling to. but not sure yet. any thoughts on those?

[LaserImage]

Based on my very limited experience, I would say you don't need any more powerful steppers than you have now. The best way to increase the performance is going to be with the Gecko. I would also stick with the 24v psu, the 48v will give you more speed but the motors will be twice as hot. For my 36" router, 130ipm is plenty fast!

If you look at the price of a good BOB and three good drives, you will pay as much, or more, than the G540 and you still have to wire it up and hope it all works. Did I mention the G540 was plug and play?

Gary

[mad_dog096]

no i dont think you did. that is good to know

on the G540 does it have a lot of accessories that you can use for it.
i was looking at the manuel and it shows that i need a vfd drive??? now idea what that is
then a relay power supply and dc relay coils.????

so do i need all that, or is this G540, motors, and powersupply going to be enough?
thx for your help and look forward to hearing from you

[CarveOne]

Originally Posted by mad_dog096 wow thats great news. ya its lots of money. will have to see. was thinking of keeping my 24v8.3A powersupply and grabbing the 495 or 425 nema 23 motors from keling to. but not sure yet. any thoughts on those?

I'll second LaserImage's recommendation on the Gecko G540.

CarveOne

[audioandy1762]

Originally Posted by mad_dog096 no i dont think you did. that is good to know on the G540 does it have a lot of accessories that you can use for it. i was looking at the manuel and it shows that i need a vfd drive??? now idea what that is VFD drive is used to control a spindle motor with MACH but you do not need to use it its just there for future upgrades. then a relay power supply and dc relay coils.???? The relays are there also for future use i.e coolant pump etc so do i need all that, or is this G540, motors, and powersupply going to be enough? thx for your help and look forward to hearing from you

Andy