3-Axis Stepper Controller

[RobiD]

Yeh, I'm interested in this question also.

I've put stronger motors on my CNC and now the UCN's are getting so hot the motor cuts in and out, so now I have to put heatsinks and a fan over them.

David

 

[Glass-Giant]

I've put stronger motors on my CNC and now the UCN's are getting so hot the motor cuts in and out, so now I have to put heatsinks and a fan over them.

Out of curiosity, what's "stronger"?  Mine are extremely wimpy.  I have my fingers crossed that they will cut foam.  I'll be ecstatic if they'll cut wood.

 

[RobiD]

I did have 3 NMB PM55L-048 by Minebea but these were missing steps due to poor torque.  They would hardly make the UCN's hot.

I came across some Sanyo Denki Step-Syn motors which have a higher torque rating and a higher amperage per phase.  These are 24vdc motors but at the moment I am running them on 12vdc.

Even with the first motors, I was cutting 4.5mm perspex in 3 layers (you know 3 cuts at lowering depths - can't think of the term).  It would cut but as I said, it would miss steps and when it went back to x0,y0 it would be out.

David

 

[GreekPIC]

Has anyone tried making heatsinks?

 

[GreekPIC]

Well, not much of a picture but it's quite simple

View attachment 37120

 

[Glass-Giant]

Even with the first motors, I was cutting 4.5mm perspex in 3 layers (you know 3 cuts at lowering depths - can't think of the term).  It would cut but as I said, it would miss steps and when it went back to x0,y0 it would be out.

I think your system and my planned one are orders of magnitude apart in terms of cutting power. 

Well, not much of a picture but it's quite simple

I guess I was making it more complicated than it needed to be.

 

[RobiD]

I have 3 x 24vdc 3.25 amp and 3 x 24vdc 3.1amp SanyoDenki motors.
What is the highest amperage that is ok to run with this board?

David

 

[RobiD]

Well, it really does give out smoke.

Maybe someone can tell my why.

I have been running the board on 12vdc from a computer powersupply.  I read an article on how to put 2 computer PSU's in series to make 24vdc.  Followed the instructions and it produced 24vdc.

With the new motors I mentioned above, they like 24vdc.
I made a heatsink with aluminium U channel, used heatsink compound and mounted a fan directly above.

I connected one of these motors to the z axis chip (this one was rated at 1.8amp) and when I powered it up, it cooked the UCN.

I had run the PSU's like that for a couple of hours to make sure it was reasonably stable and it was.

The pins that cooked on the UCN were pins 2 and 3.

Does heatsink compound conduct electricity? (probably sounds like a stupid question)

The driver board has been running as it should up to this moment.

What other reasons could cause this.

Thanks for the input in advance.

David

 

[MP1]

This chip is capable of 1.25A Maximum, which is pushing it to the limit.

MP

 

[RobiD]

Thanks for your reply MP.

I rechecked the motor and it's only 1.2 amp.

Should it have been able to handle it?
What about the power supply setup, would this have had any roll.

If I want to run 3amp motors, (Unipolar) what is the best way to do it?

Further advice greatly appreciated.

David

 

[Dazza]

Hi

Can anyone tell me, what would be the minimum system (computer system) needed to reliably run this project?

I understand that it would also depend on the software that you want to use as well.

 

[GreekPIC]

RobiD, have you checked the board without the motors? Do the UCN outputs sequence when there is a step pulsetrain?

Hi

Can anyone tell me, what would be the minimum system (computer system) needed to reliably run this project?

I understand that it would also depend on the software that you want to use as well.

Yes, it depends heavily on the software. TutboCNC works on DOS and a 486 will do. Mach 2 needs XP so the PC must comply...

 

[Dazza]

Hi GreekPIC, thanks for your reply

Well that's a shame , I was hoping that this old 386 I was trying to get going, would do the job ;D.

Maybe it will be good enough, for playing around with a prototype, to get familiar with the whole process.

 

[RobiD]

Thanks for everyone's input with this project.

I have decided to build a driver that can run upto 6A motors in a modular design that I have found.

I really enjoyed building this one as it gave me lots of knowledge.

I figure the UCN cooked from too high a current draw.

I have lots of these 3amp and 3.25amp motors and I need to build something that can handle them.


Thanks again everyone.

David.

 

[Dazza]

Thanks for everyone's input with this project.

I have decided to build a driver that can run upto 6A motors in a modular design that I have found.



Hi RodiD

Did you find it on the net, can you provide a link?

 

[RobiD]

Hey Dazza

http://pminmo.com/

I am going to build the descrete.html X 3
and the Interface - 4 axis - modular BOB (break out board)

There is also a discussion forum which is also very helpful.

By the way Dazza is a very Aussie type name, are you in Australia?

David

 

[Dazza]

Hi RobiD,

Thanks for the link,

Yes, I am an Aussie and I live in Queensland Australia 8).

Dazza/Darren.

 

[RobiD]

Dazza,

Where in Queensland, I'm on the Gold Coast.

 

[Dazza]

Hi RobiD,

I was down that way last year , we went to sea world.  It must be starting to get a little chilli down that way, it's still warm here in Bundaberg 8), I don't think winter is going to come this year ;D.


You're about five hours a way from Bundy, a little too far to come see your project unfortunately .

 

[RobiD]

It definitely is not that exciting for a 5 hour trip.

It's been many years since I've been to Bundaberg.  It's a nice part of the world from there to the top.

David