Hello Guest it is November 18, 2019, 12:26:32 PM

Author Topic: Replacing electronics on a CNC  (Read 4958 times)

0 Members and 1 Guest are viewing this topic.

Replacing electronics on a CNC
« on: January 12, 2014, 09:57:06 AM »
Hey peeps,

I've done a lot of work on my small 1000x600mm CNC router these last few days and during that last stretch of work it started freaking out. All of a sudden the Y motor starts going into random directions I tell it to go forward and it goes forward, and backwards and backwards and forwards...After a bit of fiddling I take out the breakout board, figure out where that motor is connected and I see that the part where it's screwed in has been burning. Thankfully I got it working and managed to finish the job.

Another thing is, my little router was rated 2000mm/min by the manufacturer but I can only get it to run around 800mm/min consistently. At first it works fine but after a few minutes the motors start stalling. At first I assumed that the motors just couldn't handle it but now I have a new theory...since it is manufacturer rated for 2000mm and it can perform like that for a while before they start stalling AND since I am having electronics problems I am guessing that the electronics are near death. So I guess when I try to get it to run at 2000mm the electronics just can't deliver enough power to the motors consistently cause they're old and worn out.

So I've decided to beef up my CNC by:

- Replacing the breakout board
- Adding limit switches on X, Y, Z
- Adding an estop button
- Adding one of those probes for setting the z zero (toolsetter probes or what)
- Adding a pendant


Right, so what's the problem then ? Why am I opening this thread ?

Well...I don't know a lot about CNC electronics so I thought I'd question a higher authority instead of buying a bunch of stuff and finding it doesn't work.

At first I thought that i would only need to buy a breakout board and plug my CNC motors and the rest of the stuff in, since my current router only has a single board where everything is connected (everything being the motors since it doesn't have limit switches and the spindle is a router that's manually turned on).

But (thankfully) I then did a bit of research and think that I may need a driver for each of the motors. Is that the case ?

My Y and X motors are VEXTA 2 Phase motors, 2A each and the Z motor is 1.2A

I don't know the voltage of the steppers, does it matter ?

The whole premise seems simple enough, and please correct me if I'm wrong but from what I know...plug power from transformer to the new breakout board, plug drivers into breakout board, plug parallel cable into computer. Add the rest of the stuff (estop, probe, limits) into the breakout board and configure all the pins in Mach3. Am I missing something ?

I also haven't figured out where to buy the breakout board, drivers and limit switches. I've looked around ebay and found some stuff but I'm not sure if it's any good or if it will even work together:

http://www.ebay.com/itm/USB-5-Axis-CNC-Breakout-Board-Interface-Adapter-For-Stepper-Motor-Driver-/321133023129?pt=LH_DefaultDomain_0&hash=item4ac5050f99
http://www.ebay.com/itm/CNC-Single-Axis-TB6560-3-5A-Two-Phase-Hybrid-Stepper-Motor-Driver-Controller-/321170671199?pt=LH_DefaultDomain_0&hash=item4ac743865f


Would this work ?


EDIT:

Forgot to include images:

http://imgur.com/a/uJrWj
« Last Edit: January 12, 2014, 10:10:30 AM by xxtoni »

Offline kolias

*
  •  1,011 1,011
    • View Profile
Re: Replacing electronics on a CNC
« Reply #1 on: January 12, 2014, 11:01:52 AM »
Dont have enough experience to help you but other members may chime in and help. The only thing I can say is do not buy from ebay the breakout board / drivers because you will need support for the connections and you will get non from China. Find a US vendor who is willing to support with all your questions and you will have lots of them since you are not familiar with electronics. Another item I can add is that the manuals which come with these items are almost useless to people with no experience so you will need tons of support.
Nicolas
Re: Replacing electronics on a CNC
« Reply #2 on: January 12, 2014, 11:04:11 AM »
Dont have enough experience to help you but other members may chime in and help. The only thing I can say is do not buy from ebay the breakout board / drivers because you will need support for the connections and you will get non from China. Find a US vendor who is willing to support with all your questions and you will have lots of them since you are not familiar with electronics. Another item I can add is that the manuals which come with these items are almost useless to people with no experience so you will need tons of support.

Am not from the US and won't be able to get the electronics locally.

I'm used to figuring stuff out myself though, been like that pretty much with every machine I've ever bought including this CNC mill. Even when one gets service locally the people doing it don't have a clue what they're doing so you're on your own most of the time.

Thanks for taking the time to post, much appreciated.

Offline Tweakie.CNC

*
  • *
  •  8,002 8,002
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: Replacing electronics on a CNC
« Reply #3 on: January 12, 2014, 11:13:44 AM »
Hi Xxtoni,

My preference would be to spend a little more money and go for the Gecko G540 (or other of their similar products) http://www.geckodrive.com/geckodrive-step-motor-drives/g540.html

Backup, support and excellent documentation.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Replacing electronics on a CNC
« Reply #4 on: January 12, 2014, 11:23:22 AM »
I was hoping that you would make a reply Tweakie.

You are probably right but in this case I'd rather not invest too much money into this machine. We are about to buy a 3050x2050mm machine but would still like to keep this one operational cause it's more convenient for smaller jobs but I don't know how much life the steppers have in them left anyway and if they were to fail I wouldn't go through the trouble of replacing them.

Offline Tweakie.CNC

*
  • *
  •  8,002 8,002
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: Replacing electronics on a CNC
« Reply #5 on: January 12, 2014, 11:41:19 AM »
My guess would be that so long as you have not badly overheated your stepper motors they are unlikely to fail.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Fastest1

*
  •  927 927
  • Houston, TX
    • View Profile
Re: Replacing electronics on a CNC
« Reply #6 on: January 13, 2014, 08:52:14 AM »
   The G540 or MX3660 are both great units that contain everything but a power supply to get you up and running. You could most likely reuse your old power supply.

   If I were to buy a BOB, it would be a PMDX126 due to its robustness. Then you would have to buy drivers also. the 2 above units are self contained and small.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: Replacing electronics on a CNC
« Reply #7 on: May 28, 2016, 01:22:04 PM »
thanks, so I should not worry about the heat of my stepper motors?

Offline Tweakie.CNC

*
  • *
  •  8,002 8,002
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: Replacing electronics on a CNC
« Reply #8 on: May 29, 2016, 01:36:39 AM »
thanks, so I should not worry about the heat of my stepper motors?

Stepper motors are designed to run at their rated current. They will run hot but if the outer case temperature is above 65 deg.C then I suggest that you reduce their drive current accordingly. (high quality stepper's can handle very high temperatures indeed but the cheaper versions may suffer failure if allowed to get too hot).

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline rcaffin

*
  •  1,003 1,003
    • View Profile
Re: Replacing electronics on a CNC
« Reply #9 on: May 29, 2016, 06:21:09 AM »
So the Stepper motors are OK at the start but then they start to fail? Like, when they get hot?
Do you have old round steppers? If so, be aware that the magnet inside them fails with time, and heat.
Sounds to me as tho' your steppers are reaching end-of-life and may need replacing. Buy modern square steppers: they are much better. Guess how I know.

Cheers
Roger