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

[itsmillertime]

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

[JAZZCNC]

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.

[itsmillertime]

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.

[Jonathan]

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

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.

[itsmillertime]

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

[JAZZCNC]

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.

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.!!

[itsmillertime]

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