[CPH-J]

Hi everybody!

i'm a long time looker, first time writer here.

I've been reading and learning alot here - after the build of my first cnc (all mdf, joes 2006) and this is more or less the result of what iv'e learned through this forum. My machine is drawn from scratch, and implements some of the stuff i find usefull when using it in an everyday production. I work as a cabinetmaker in a joinery in copenhagen, and this machine is intended for prototypes and template making - maybe some small production of neat things.

The problem with me was that i really didn't know anything about any of the aspects of cnc building (and how to use one really). I know a bit more now, but in reality it's just a drip in the ocean.

i have had alot of problems with this machine - some of them solved, other ones not so much And from what i've read around here, the expertise and willingness to help is just incredible.

But i don't expect any help, unless i share what you guys are helping me with. So here we go. i'm sorry for the grain on the pictures - iphone camera, is not the best in the world.

[CarveOne]

It certainly looks like you have all of the equipment available to do a nice job with the parts cutting and building. Very nice looking machine.

What kind of problems remain to be resolved? Mechanical, electrical, software? Folks here seem to like a challenge.....

CarveOne

[CPH-J]

And now for my first problem. i've been searching and searching and i simply couldn't find anything like this anywhere. I Jumped in the china team, and ordered the spindle with the matching VFD. It ran as it should when i fired it up.

When my machine was at the point where it could start making money, we moved it out in the workshop, and started cutting some test pieces - ran perfect, only the noise from the cutter hitting going through the wood was noticeable.

after it had cut the test pieces - including the oak tray, with the deep pockets and the holes for the different holders for the collet as seen in one of the pictures above - I started cutting the real pieces for costumers, and thats when it happened.

The spindle suddenly stopped after running for about 20 min. It stopped right in the middle of the piece with a 7 mm stepdown, which really wasn't that nice.

the VFD gave me an error saying EOCA. According to chai (mr. chinese supplier) it meant over-current while speeding up? (what?) well, i tried again, after about 15 minutes it stopped in the middle of the pieces giving me the error EOCn meaning (quoting chai)

"Over electric current that is caused by the Vatage sudden change. That means the Votage is not steady."

whatever that means, i have no idea what to do about it. When i start the spindle now, the VFD gives me a nasty loud humming noise and the spindle makes some wierd high pitch noise as well. it then runs for 8-15 seconds then stops giving me the EOCn.

any clues? is there any chance of getting this to run again? the total running time of the spindle is about 1 1/2 hour, thats gonna be quite expensive in the long run!

[CPH-J]

Thanks Carve,

other than my spindle problem - which is quite severe. It's like having a car without any wheels on. It's radio interference. every radio in the radius of around 6 meters, is being nuked, resulting in no music when it's running i'm thinking the gecko-to-stepper wires may have something to do with it, even though they're shielded. i'm missing some proper way of homing and limiting, but i'll ask that question when my spindle problem out of the way. Thats really the most frustrating right now.

CPH-J

[ger21]

My guess is the VFD is interfering with the radios.

There's a lot of info in these threads, including documentation for the VFD and how to set it up.

http://www.cnczone.com/forums/showth...threadid=68736

http://www.cnczone.com/forums/showthread.php?t=74592

[ger21]

And btw, that's a really nice looking machine.

[mactec54]

Hi CPH-J

To stop the radio interference you need to have shielded cables the sheild needs to be grounded at the source end ONLY & all your EMF will be gone

With having this interference it will afect all of your electronics in some way

[CPH-J]

Thanks Ger21, i have the english manual already, which i've read and double checked every single point on the vfd with what's stated in the manual - nothing helps. the thing that worries me the most is the humming noise coming from it. it's loud and it seems like it's causing the high pitch in the spindle as well, or the other way around, like theres too much power in the system somehow. it wasn't there before, and now it's there every single time i start it up! i've checked the wiring, no shorts.

is there a way for me to check if there's a defect in any of the phases in the spindle?

the reason i'm suspecting the stepper wire for the RF interference is because i had the whole system up and running without the wires connected to the steppers and the radio was crystal clear.

mactec54, my stepper cables are shielded, with the cable connected to ground. i have common reference for all my dc lines as well. but i'm doubting whether or not to connect my dc common to earth? any thoughts?

[mactec54]

You need to have the main power feed to the VFD to have shielded cable & the shield needs to go to ground only ground one end

The VFD to the motor needs to have shielded cable as well ground one end the same as above, the VFD may have some damage from regen or spikes set it to have a long ramp down before stopping this will help with the regen

[Hirudin]

Wow! Nice machine. It looks like you've really done your homework.

About the noises coming from the VFD, that sounds real bad to me (a non-electrician). If I were you I'd have a fire extinguisher handy at the very least.

Although I think you've probably already considered this, I'll "throw it out there" anyway: you can do a rudimentary check of the phases of the motor. You might want to research this further - since I haven't even hooked up my spindle yet, much less trouble-shot it I may not have my facts straight... Anyway, check the resistance between the phases. I'm pretty sure there should be roughly equal resistance between all of them (~9 ohms was one person's measurement if I remember correctly). Also check for continuity between all the phases and the ground, there shouldn't be any continuity (of course). [edit]Do these checks with the motor disconnected from the VFD.[/edit]

The VFD can be powered-up without a motor attached, right? If so disconnect the motor and see what happens. If the buzzing continues I would conclude the VFD is broken somehow. I'd suggest asking Chai to cross-ship you a new VFD. If the buzzing goes away I'd guess the motor is the thing which is brokt, see if he'll cross-ship you a new motor.

[CPH-J]

Thanks mactec. I didn't know i had to shield the power cable as well. i have a ac filter of some sort laying around, i'm gonna try to put it on the power feed as well when i get the chance.

Thank you very much Hirudin, from the performance of it, i would say i have done my homework too

A little update on the spindle situation though. A good one!
even though i did a check on all the settings, i apparently needed to reset it anyway. I did that, and tried to reprogram it, and then it ran perfectly!

i measured the resistance on the phases. They were all giving me 25 ohms? thats a bit far from 9? i have a new problem with it now. the humming is gone from the VFD, and only the fan is audible - but sometimes when i try to start it the spindle just twitches a little bit back and forth, while it sounds like it's speeding up, but it's really not doing anything. sometimes i have to do it a couple of times before i get it going.

I would almost say it looks like the phases in the spindle doesn't manage to push it forward to the next phase to really get it up to speed, if that makes any sense?

also, i had it running for about 20 min, cutting some solid wood, with the load being around 1,5A but when i zeroed it - leaving it running - it still showed around 1,5A (normally 0.2A with no load) turning it off and starting it again got it down to 0,2A again. It just seems a bit strange to me.

anyway, i've connected the KA,KB relay to my e-stop input, programming pd053 (the KA KB relay) to react when the VFD gets overloaded - hopefully stopping it from ruining anymore pieces in case of error.

so far so good

CPH-J

[mactec54]

It sounds like you need to change some setting in the drive like giving it a longer ramp up to speed time this will be better on the drive

Yes to do things right so you don't get problems you need the shielded cables on everything the filter will help but won't solve all of the RF you are getting