[sanekc]

Hello all! I'm new here, long time reader Just finished to install my machine (3 axis ball bearing 800x1000 working area, aluminium extrusions and 15mm plates) with one of this uncalibrated kits from china (3x425oz motors, DM542 stepper drivers). But yeah, first try, first setup and at 15ipm and plus it stalls every 2cm with some sort of resonance...

Played with microsteps and such - same...

Here the video of this phenomen :
https://www.youtube.com/watch?v=WWSMkfx2Vn8

Really need an advice here... What could I do? I guess geckos or dampers would be the aswer but I prefer to ask first.

Thought about buying geckos but I just can't throw more money in this machine, my wife will kill me plus this machine is for hobby purpose only (guitar making, engraving, little design things).

Will post the video

I've stated by bying an 48v power supply to improve the torque as it's the 24v or 36v that's come with this kit. Waiting for the delivery now...

Have a nice day, and really sorry for the sloppy english, not my native language

Alexandre.

[coherent]

Micro step settings won't effect the torque very much. If the screw turns freely and there is no binding or resistance, then I'd look at the settings and motor tuning next. The symptoms you describe sound more like settings than the electronics themselves. Lower the acceleration settings and see what the max you can set before you loose steps. Start out at 5 or so. It's hard to tell in the video but I've seen acceleration settings set to high cause that issue. 15 ipm is pretty slow. I'd expect much better on that machine. The import drivers perform ok, and 425oz steppers should be plenty. Even a 24v or 26v power supply should do much better than 15 ipm. Double check any dip switch settings on your drivers power settings. and make sure you're using what matches your power supply. I've seen the dip switch settings printed on the driver that were not correct also.

[sanekc]

Thank you, I will definetely try your method and see what happens. Yesterday in frustration I checked rails and ballscrews but everything is clean and sliding freely... Now I'm at 10 for the acceleration, will try to slow it down!

If I can at least have some 40-50ipm with this machine it would be really nice haha

[coherent]

I think 40-50 should be no problem and I expect closer to 80 or 100. If you haven't, check the output voltage of your power supply and triple check all of your wiring. You didn't say what amperage your steppers are, (4.2A ?) but again, check the dip switch settings on your drivers and make sure they are correctly set for your stepper motors. I'm not saying you don't have them correct, but it's not uncommon to see folks reverse the dip switch settings. In the case of your drivers (sw1-sw3) all set to OFF which would be for 4.20A when they are actually all ON which would be 1.0A.

[sanekc]

Good evening!

My motors are 3.0A rated and my power supply is 36 volts (after checking at my shop). The closest setting on the driver is 2.8A. I've tried 2.0A setting with no success... Maybe my wiring is off I don't know? I put the picture just in case (if anyone can understand what's happening here) :

https://www.dropbox.com/s/kwy6stge6z..._2612.JPG?dl=0

Tried acceleration with no success. I'm a metric guy so i've started at 125 (eq 5 inches) and no success. So i've tried 5mm! And still when it reaches the velocity it stalls, damn :/ Can't even reach the 15ipm mark (the maximum i've got is 300mmpm). Maybe it's my motor to structure connection, I've just put 4 screws with 2 washers so motors are almost in contact with plates, then coupler. No stand offs or such.

My kit is this 1 axis Nema 23 stepper motor 425 oz.in DUAL & Driver DM542A 4.2A, 128micstep CNC | eBay

My DIP swithes are on on off off for the current and off off on on for 1600 microsteps.

Anyway, thank you for helping me out, really appreciate it

[awerby]

What's the induction on those motors? Many of these ebay "kits" include wildly mismatched motors, drivers and power supplies. You might have motors that require more voltage than the power supply can provide, or that your drives can tolerate. (Hint: the nameplate voltage has very little to do with the actual amount of voltage they need in order to perform well.)

[sanekc]

Inductance is 9mH i believe!

[awerby]

That's likely the cause of your problems. Using the formula (square root of the inductance in mH times 32 equals optimum top voltage for maximum speed without overheating) those motors really want 96 volts DC supplied to them. Since you're only giving them 36, it's not surprising that they're underperforming.

[sanekc]

so I guess I'll need to

1. change motors to low inductance ones to match the voltage I can give them
2. change everything else but motors

Stuff like this for exemple? Nema 24 Stepper Motor 3.1Nm 3A 8-wire 8mm Dual Shaft CNC Mill Lathe Laser Router | eBay

[awerby]

I think option 1 makes more sense, since it's hard to find inexpensive drives that can handle 90 volts and the new power supply will cost something as well. That link brought up a whole raft of motors, so I can't comment on any of them in particular.

[KH0UJ]

on my opinion tune it on it`s stable moderate speed first, maybe something like this

Attachment 359328

Then slowly bump up the speed and acceleration until it stalls then back again, try to hook up a multimeter on your power supply too, then try to move the XYZ simultaneously if it drops then maybe your need to have an independent power supply in each axis. the moment the voltage drops for sure it will stall.

[ger21]

Try some rubber washers under the motor. If it's resonance, it might help some.

What pitch is that screw?

[sanekc]

Thank you, kind people! I will sure try firstly play with settings and stabilise my motors with something, then when my 48psu arrives, i will try to power motors independently, if it changes something I know where the problem is and buy a third psu maybe to power every motor with at least 48v. And if the problem persists well I will try to buy some new motors with max 5 inductance and double shaft to dampen it in the future with the brilliant design posted on this forum!

My ballscrews are rm1605 which i belive are 5mm pitch!

I'll keep posting! Have a nice day.

[KH0UJ]

Honestly im one of the few guys that dont know (not interested) how to calibrate using pitch or TPI on the ball screw, but I can calibrate it by only using it`s optimum acceleration and speed of a certain stepper motor and a metric caliper is it wrong?

[coherent]

I agree that a lower inductance motor in the 2.5 - 3 range would perform better with your system, but I'm not convinced that they would be stalling out at such low speeds if your axis/screws are moving freely. Hard to diagnose via the forum & posts. It's impossible to see if the wiring is correct by looking at the photo. I'd connect only one motor to one axis and get one working first.
I hope you determine the cause and please let us know what you find.. Good luck.

[sanekc]

Could you guys give me an advice on motors? which I should buy but i dont want to spend too much. So another set of 425 or less with half inductance (max of 5)

I will draw a scheme in the evening to show you my witing, maybe something wrong here

[davy182]

Do your drives have adjust ability on the step multiplier or micro step. If you are at full step trying moving it to a couple micro step functions out. I have had some motors dislike full step settings and stopped stalling after I put them into a micro step setting.

[sanekc]

yes, I have microstepped the motor to the 1600 microsteps!

What you guys think, I have a Dell Optiplex pc which give me 3.3v impulses, maybe the issue is here?

Could you please tell me if my wiring is ok? Thank you in advance guys!
http://www.cnczone.com/forums/attach...d=359498&stc=1

[KH0UJ]

For sure your Dell Optiplex is very much OK, all of our CNC routers are driven by Dell optiplex 320, your wiring is OK too, can you post a screenshot on your motor tuning and set-up page?

Ohh one thing how big is your wires used on wiring your main stepper motors? on our machines I replaced it with AWG # 16 flat cord duplex wires because of intermittent motor stalling, since then it`s running fault free all year round.

http://www.cnczone.com/forums/attach...d=359518&stc=1

This is the picture of the wires I converted when I changed the leaking water hose, these machines are running a year round every day, the water hose got brittle less than 2 years though.

[sanekc]

For sure your Dell Optiplex is very much OK, all of our CNC routers are driven by Dell optiplex 320, your wiring is OK too, can you post a screenshot on your motor tuning and set-up page?

Ohh one thing how big is your wires used on wiring your main stepper motors? on our machines I replaced it with AWG # 16 flat cord duplex wires because of intermittent motor stalling, since then it`s running fault free all year round.

http://www.cnczone.com/forums/attach...d=359518&stc=1

This is the picture of the wires I converted when I changed the leaking water hose, these machines are running a year round every day, the water hose got brittle less than 2 years though.

I dont know exactlyhow big the wire is but it is kinda fat, will check this out too!