CNC router occasionally makes jarring noise and home jumps when it does this. Help!!

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Originally Posted by JAZZCNC

Nah but I do have a pallet of Latex I can sell you.???. . . .Gloves. :hysterical: . . .( Also Nitrile and Vinyl if that's your fetish. . Lol)

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OMG lol What did I just walk back into? :whistle::beer:

I wanted to update you on my progress with getting this jumping/ noise issue out of the way. Well... I figured that you guys Jazz I think mentioned it first that I was expecting too much and the speeds were too high with the rapid and cutting settings.

Well, Lo and behold after trying lots of different tuning combinations. I discovered setting the speeds too low also made for some horrible sounds. But I came across a another post with some supplier recommended settings. That were indeed a lot slower than what I had been gave.

Attachment 11297Attachment 11298Attachment 11299

These settings were actually found to be the best for my 6040 machine. And they are

steps velocity accel' step dir
X 320 2000 200 10 5
Y 320 2000 200 10 5
Z 320 800 150 10 5


My old settings that made the occasional noise and stalled the motors were

steps velocity accel' step dir
X 320 3000 200 3 1
Y 320 3000 200 3 1
Z 320 800 200 3 1


It sounds loads better now and doesn't fly about making my table shake slightly with the speed of movement of the gantry.

I have re-cut a few test pieces and haven't had the horrible sound or any missed steps.... yet ;-) Never say never eh!


I just want to say a really big thanks to all you guys for all of your invaluable advice I really do appreciate it and would have been stuck without all your help. cheers guys

Andy :-)

Well, Spoke to soon! Although the motor tuning appears to be better and it certainly still sounds better. I have had the same problem come back. The stalling and the engraving being out of line by about 10mm as though the motor stalled again (complete with grinding noise!)

I turned the power off and swapped over the X and Y axis connectors at the 'blue' controller breakout box. Looking to see if the fault would swap over the the X axis (My fault has always shown on the Y axis so far)

Lo and behold I rotate my workpiece by 90 degrees and power up and run the machine again. The error appears again exactly the same (but without any really noticeable grinding on the machines X axis. Apart from the engraved text appearing backwards the error is in the same place on the workpiece. This I think tells me that the problem is in my Y axis driver board? Plus my Z axis (at approx the same time as the initial Y axis error reappeared seemed to plunge deeper by about 2mm after/ same time as the Y axis stalled. Inside the breakout box the driver boards are separate.

Am I right in thinking that it can only be a crappy control box (mixed with maybe crappy unscreened -and not star earthed either..)

I'm now looking at replacing the existing chinese cable in the 6040 router with screened cable is this the best thing to do and any links to the best 4 core stuff to buy for the job please?

Also I am going to need to replace the break out box. What is the best and easiest stepper controller solution in the UK. Balancing cost and quality. I would stick with the stepper motors I have for now but probably need to upgrade this crappy control box.

Would really like to hear your suggestions guys.. :-)

Thanks again Andy

Calm down Mr mannering don't go scraping things just yet.!! . . . Still some other things it could be and if you have separate drives there's half a chance it's just a setting or pulse issue.!

Looking at your motor tuning with 320 steps Per setting and presuming a 5mm pitch screw means the drives must or should be set to 1600 micro steps.
This is relatively high for these machines so It could just be your system can't handle that many pulses and your getting missed steps.?

So first we need to confirm this so can you give us a good quality picture of the drives and there wires and Dip switches if any.
Try and find out ther PSU voltage.
Next what is the Kernal speed set at.? You'll find it in ports & pins.

Show us more before spending any money.

Lol Cheers Jazz ;-)

Just got frustrated with trying to get it running consistently! I have just gone out and taken the case off and had a look inside.

It looks like the switches are set for 1600microsteps. From the PSU I can see on the label (DC output 24v and current 12.5A) outside case says drive voltage 24v DC drive current 3A.

The kernel speed is set at the lowest setting 25khz? I have attached some pics of the controller.Attachment 11307Attachment 11308Attachment 11309Attachment 11310Attachment 11311Attachment 11312Attachment 11313Attachment 11314

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Originally Posted by itsmillertime

The kernel speed is set at the lowest setting 25khz? I have attached some pics of the controller.

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320 step/mm * 2000 mm/min = 640,000 step/min
640,000/60=10.67kHz
10.67kHz is less than 25kHz ... so that shouldn't be a problem.

Thanks Jonathon for showing the workings of that, makes it a load easier to understand the reasons behind the settings. cheers andy

Quote:

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Originally Posted by Jonathan

320 step/mm * 2000 mm/min = 640,000 step/min
640,000/60=10.67kHz
10.67kHz is less than 25kHz ... so that shouldn't be a problem.

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Jonathan I was more concerned that the Kernal speed was set too high which can cause strange happenings like this.!!. . . Long shot but it happens.

Andy.

First are you 100% sure there's no mechanical issues.? No binding etc. It won't take much stickage at these speeds with such low powered motors/drives to rob torque.

If not then next try cutting the same part but in air without spindle running. This will eliminate VFD/Spindle interference.

After that then carefully inspect wires at the motor connectors and at the BOB/drives for any lose connections.

The drives are better than some of these machines but still cheap low quality drives. That said they should do this job thou with just 24v you can't expect too much.

Again I'm clutching straws here but you could try setting the micro stepping to 400 on drives and see if it changes anything. Just do the problem Axis first to see if it alters any thing.
You'll need to go into Motor tuning and set the Steps Per to 80 and retune the motors. You'll see can get much higher velocity on that axis now but I wouldn't anyhigher than you have it now.

Failing any of this working and machine being mechanicly sound then scrap it all and get this MX3660 - 3-Axis DSP Based Digital Stepper Drive Max 60 VDC / 6.0A along with 48V PSU.
It will transform the machine and I'm pretty sure it will fit neatly into your existing box with only slight modification. It comes complete with Digital drives, built in BOB and Spindle speed control.
Rated upto 60V 6A and will easily run motors at 50-55Vdc with a unregulated PSU so if you want to upgrade motors to say 3nm at a later date then you can. . . . .Or take it with you to another bigger machine.!!

Hi

My friend had a similar problem a few years ago, after a lot of messing about, we found a few important but simple things helped out.

1. Check your parallel cable, and both connections, ( someone on here already mentioned it ),
2. Try not to cross any of the cables for the axis, especially with the spindle cable and keep them away from estop cables. but try rout them away from each other, or at least insulate them a bit.

The version of Mach your using, did it come with the machine

3. Some of the Chinese suppliers send out hacked versions of mach ( can not remember the build number ), and its full of bugs,

2 years ago, when dealing with a problem on my friends machine, the hacked version of mach was buggy on the axis drives and spindle speed setup for slow spindle rates.

edit. just looked at your wireing again, you have 3 axis power cables running very close to your other wires, If your Y axis driver is the one on the right side, i would route them power cables elsware, or at least dont let them get close.

Cheers Jazz,

You have been pretty thorough with your suggestions and I do appreciate you taking time out to give your advice. I will go over the machine tomorrow. take off the suspect axis stepper motor and move the gantry by hand to see if it is binding / any resistance present.

As for possible interference from the spindle? I did think of this before. So I've ran g code with the spindle powered off/and in the air and its still stalled. Its very random when it happens.. but it happens frequently enough to prevent me working on anything expensive or intricate. Possibly happens once on every other job. But its enough to ruin whatever I'm doing!

I will physically swap over the x and y driver boards and see if the fault does indeed transpose to the x axis as I suspect. I can barely live with the one problem. But with the Z axis losing its zero. Its a step too far!! boom tish ;-)

Going to also swap out my parallel desktop cable for another one I have and change/ ensure my desktop is in standard PC mode not acpi..

Then I will try the changing steps as you suggest and if that doesn't work after inspecting all cables etc?

I will replace/upgrade all stepper cables and shield the vfd cables. Earthing all of the screens.

Still not working? I will be delighted in swapping out the controller with the one you suggest.

Having these issues are a great way to get to know my way about the machine so I view it as a learning exercise in getting to understand how it all works.

Will let you know how it goes tomorrow. wish me luck!

thanks again for all the help

andy

thanks George for your reply too. only noticed your reply after answering jazz so we just cross posted!

Yes the Mach that I have was supplied on a CD and I'm sure its been unlocked as it never asked me for a key. not sure of the version I will have to look that up tomorrow. Going to get a legit version of Mach but need to try and get this machine running first( if possible!) as this could really break my budget the way this is going!

thanks for the cable suggestions I'm going to give that a shot tomorrow.

will let you know if I find anything!

thanks andy