Electronics for New Machine + Chinese Spindle + VFD

[mturneruk]

Yep. Steps per are correct. Distance is correct.

I am now suspecting that i might have a faulty UC300. A few minutes ago Mach3 was not recognising the UC300 for some reason when the USB lead was plugged in. I wiggled the lead, restarted the PC, restarted my electronics, but no connection (UC300 power light was on though). So i disconnected everything and took the lid off. Everything looks normal inside my box Checked connections etc. I did notice that the case (which is earthed) may of been touching the outside metal part of the USB connector. I fixed this and plugged the USB in again and it then connection was established ok. Not sure this is related to be honest.

So I did a mid air cut with the spindle and extraction running and that was ok. So then I tried to re-cut the part that screwed up before as a test and not only did i get a few nasty jolty noises during the cut, halfway through Mach disconnected from the UC300 and the job stopped. After that I reconnected the UC300 and tried jogging and doing another midair cut and that worked ok.

All the problems seem to happen when i am actually cutting something and not when jogging / air cuts.

Ideas i have had so far are....

1. Faulty UC300.
2. Vibration from the machine during cutting effecting the electronics somehow which are under the cutting table.
3. Noise. Surely this would effect air cuts as well though.

I have tried several USB leads all shielded and different ports on the PC and that's not the problem i don't think.
Lost at the moment. Any ideas much appreciated.

[JAZZCNC]

I did notice that the case (which is earthed) may of been touching the outside metal part of the USB connector. I fixed this and plugged the USB in again and it then connection was established ok. Not sure this is related to be honest.

Yes this would cause problems because it would create an earth loop with the PC. The USB gets it ground from the PC earth.
Don't earth the case of the PC to same Star Earth point used for the control box. The Pc gets it's earth from the Mains directly thru the plug.

Vibration or resonance won't cause these problems. It mostly makes the motors run rough and lower performance not miss steps etc unless really bad.

USB can be flaky to start with so if you have any poor wiring connections or noise going on then it will be picked up.

But Before starting on the wiring I'd go over the mechanicals with fine tooth comb to make sure no lose couplers or binding issues.

Then Go over your wire connections very carefully. Make sure Power wires are away from signals. Esp around the VFD.

Trying to diagnose problems like this is difficult from distance because it could be so many things. Often it's something really simple or silly.!!

[mturneruk]

I have just proved that it's related to load on the cutter.

I tested cutting about 3mm passes of birch ply (now scrap) while Jogging. After only a few centimetres Mach3 would stop (As i mentioned before when i was surfacing my bed).
It just did it about 10 times in both X and Y directions. Each time no error condition was present in Mach 3.

All i needed to do was to go in the other direction and then it would work in the direction which had stopped working previously (With a bit of a jolt to start).
I really don't think it was my keyboard. It'a a Steel series shit hot mechanical key thing.

Having got it to do that consistently, as soon as i rose out of the material and did the same thing, it did not stop at all.
This is consistent with my experiences so far.

Could this mean the drivers are at at fault in some way. Something to do with all those dip switches possibly ?
Overheating, protection kicking in or something?

Maybe I should of gone for those Leadshines as you suggested.

As usual. Thanks for your excellent replies Jazz. Is this your forum ?

Cheers
Martin

[Neale]

Could this mean the drivers are at at fault in some way. Something to do with all those dip switches possibly ?
Overheating, protection kicking in or something?

No guarantees, but I saw something very similar when I first set up my 3D printer. What's the max current setting on your drives? Yes, decode those DIP switches! Could be that if these are set too low, you are just not generating enough torque to move the spindle under cutting load.

[mturneruk]

I hope your right.

I have current set to 3.8 as recommended by CNC 4 You.

e.g.
SW1. Off
SW2. Off
SW3. On

SW4 is set to off. (e.g. Half current mode).



Edit : I am running 10 Microsteps.

Cheers
Martin

[routercnc]

Don't know if this is related to your problem or not but from time to time in the past I've had e-stops when the cutting loads suddenly increased. If the cutter was clogging up (aluminium) and slowing or stopping the spindle it could trip the e-stop.

I assumed this was increased electrical noise from the VFD as the amps shot up, and any long cables were like antennas which fed this into the BOB. In particular the long run to the Z seem most affected.

Since upgrading to 24V on the e-stop & limit circuit (i.e. relay into the BOB with very short wires) I've not had an unintended e-stop due to sudden load increases.

So when you do an air cut things are different to doing the real cut in terms of VFD load and this is another factor to consider in the diagnosis. Having said that if Mach3 is not e-stopping then it surely points to something in the UC300 or USB?
....
Not sure if you were joking but this forum was set up by Lee Roberts [and we are all indebted to him for doing so]. Dean (JazzCNC) is a massive contributor so you could be mistaken for thinking that, but it is not his creation. On that subject I think Jonathan is still a moderator ?

[JAZZCNC]

As usual. Thanks for your excellent replies Jazz. Is this your forum ?

NO the Forum belongs to and is kindly run by LEE Roberts. . . . . . . I just come on and cause trouble.!


Your problem is NOT Load related. No cutting can or should stop Mach3 from working. The motors can stall or miss steps but will never stop Mach working or break connection to Controller.

[mturneruk]

Just re-reading Jazz's post Number 132.

The Amps should match or be close to the Motors rating as possible. Good drives will let you set exactly to match motors but If no exact match then set to next lowest. You'll just have lower than rated Torque but better than going higher and having more motor heating.

Here is a link to the spec sheet for my motors.
http://cnc4you.co.uk/resources/Stepp...1-03%204Nm.pdf

It seems to suggest they are rated for 4 Amps (if I understand the spec correctly). Hence the 3.8Amp suggestion i guess.

So where do i go from here i suppose is the question.

[mturneruk]

Hear you Jazz.

So you don't think it's load related.
In that case is it possible that the VFD is generating a lot more noise when it's cutting rather than just running ?
Is the next test to take the VFD out of my enclosure?
Nightmare...

[JAZZCNC]

Hear you Jazz.

So you don't think it's load related.
In that case is it possible that the VFD is generating a lot more noise when it's cutting rather than just running ?

Yes it's possible but whether or not that is the problem I'm not so sure.! The easy way to check is to remove the VFD from the Control box.
The VFD cables running thru the machine shouldn't be a problem provided you have a little separation from signal cables.

Like I say this won't be load related because I've pushed cutter thru MDF without spindle running and motors not stalled before material is ripped from bed so with the small DOC and low Feed rate you have been using then it won't be load. Even with a very tired cutter it wouldn't cause this problem.!. . . Again thou easy checked just throw a new cutter in it.!!

The amps are fine at 3.8A. 2000(10x) micro steps are fine so you have no issues there.
It's not the drives protecting them selfs, they would just fault and blink at you showing what cause the fault.

Can you make it do it and video it. This may highlight some things. Also show the Electrics and wiring around machine.