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

looking again at your pictures, i would definably suggested routing the wires away from each other, especially the power cables away from the data cables. I would also check that anything supposed to be earthed to the case, is firm

I think mach3 comes in a trial version from there site, ( limited to 500 lines i think ) If your only running at 25kh, the hacked version might not affect you that much, in fact, it was only the spindle controll that we found buggy. Because of all the other things you have tried, its probably interference with the wires, or the driver board ( cheap to replace ) .

Mach3/4 well worth buying a licence for, the support and help you get on there is like the help you get on here, saves you hours of reading and headscratching

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Originally Posted by george uk

looking again at your pictures, i would definably suggested routing the wires away from each other, especially the power cables away from the data cables. I would also check that anything supposed to be earthed to the case, is firm

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It won't hurt doing this but I would be very surprised if this is anything to do with it has he's only running 24vdc. Only the 240V mains voltage will be worth routing signal wires away from has 24Vdc won't produce much noise.
When it's noise it's often a very slow process of missed steps or the complete opposite and it's tripping drives or E-stops etc. If the VFD isn't affecting it then wires being a little close to each other won't be.!

The Parallel Cable is always worth swapping out for another when having trouble and it will probably been me who you've seen suggest before George has i've seen it many times. Thou I don't think it's that in this case other wise would have siggested it.

Andy george is correct about the Hacked version of Mach3 and now knowing this I wouldn't do anything else untill you have un-installed it and replaced with the genuine and currant lock down version.

To be honest I'm still thinking it's a Mechanical issue with binding that's robbing the low amount of torque that's left at the higher feed rates. These motors are 4 wire motors so can run out of torque very quickly when rpm rises and with only 24V then there won't be very much torque to start with.!

Ok guys,

I spent a few hours this afternoon stripping down bits and taking the bed off and removing the stepper motors from the router trying to look for any mechanical binding etc along the Y - the gantry driving axis.

It doesn't sound particularly smooth but I dont have much to compare it to. The gantry moves quite freely by turning the leadscrew by hand. I can freely push the gantry across the length of the machine and back with a gentle concerted push by hand. It's definitely less resistive in the middle section and approx the last 4" at either end the resistance increases by about an extra 15% and the noise from the ballscrew is slightly more pronounced and it's just a little more 'jerky' towards the last 4-6 inches of travel.

I checked the travel and the resistance of the x axis and this is noticeably smoother to push but I think thats because it's lighter and better supported on the 2 bars and less to travel. It does make a similar noise to the Y axis it's just less 'clanky' and smoother.

I moved the gantry right up to the ends and looked for gaps/ being square with the frame. At one end of travel (near the stepper motor) it's pretty much bang on. But at the other end of of the router I measured the gap at approx 2mm in one corner with the other corner at 0mm flush with the gantry. 2mm is quite a noticeable gap across the end. I have attached a photo.

So what's the best way to work out if its true? Could this be causing some resistance? I guess measure across rails at one end and do the same at the other? I haven't removed the lead screw or anything yet as I didn't want to really disturb anything else until I asked here!!

Is there any easy way of doing this, maybe loosen up the rails and run the gantry from the one end to the other? Then tighten up the rails? I checked all the allen screws and all are tight.

I may have found a possible cause of the motor stalling. One of the grub screws on the Y axis coupler didnt feel very tight (possibly loose) and maybe causing the coupler to slip when the load got too much? Not 100% certain that is it. But it's the very same axis that has had the problems.

I guess what I'm asking is, is the noise my machine makes when moved by hand (pushed) normal? Should I expect any resistance at extremes of travel. And whats the best way of making sure its square/ true and not a bent ballscrew.

Where should I go from here please guys?

While I have the bed up and I'm looking for biding/mechanical issues I want to rule them out I guess. Also should there be any oil of grease on the ballscrew? No nipple or any obvious lube in place.

http://youtu.be/5mxulmQ8Ivo

Sorry that the video is 3 mins long but it shows the freedom of movement and sound of my y and x axis being moved by hand.

Below is a photo of the gantry with the gap approx 0mm/ flush at one side and 2mm at the other. I took measurements to show the difference in the gap.Attachment 11327Attachment 11328

Attachment 11326

Thanks again for all your advice. Just hoping to rule out any big mechanical issues before going for drivers etc..!

andy

Andy wouldn't worry about the 2mm gap it's just the frame thats out of square which doesn't mean a lot. More important that the x axis gantry is square to the Y axis rails and the y axis rails are parallel to each other.

The Y axis doesn't look to be binding too much but it does look and sound very dry so get some grease in the ballnut or at least bit of light lube oil on the screws.! . . . If the coupling was loose then it's 90% chance you've found your problem.

One thing I didn't like the sound of was the rattling when you grabbed the end of the ballscrew. Check if the ballscrew is floating back n forth by grabbing the end, there should be no movement.

If this is ok then I'd just grease and lube everything and put back together. If the ballscrews don't have a small flat on the end then file one on to give the grub screw a flat surface to grip on then Loctite the coupling grub screws.

I had a bit of an issue with getting tighter at one end. I loosened the stepper bolts and coupling screws and bearing block and found the tightest spot then jiggled all the above to try and get it into the best position to bind the least. Seems to have done the job. I also had a slightly less tight coupling screw - wonder if it's a symptom of binding?

richie - thanks mate for your reply. It could be something like that causing a slight bind but I was unable to replicate any real significant difference in 'feel' during pushing the axis' by hand.

Sooooo, what did I do next? Well after getting really fed up with it all. I decided to take the advice of you guys especially jazz and his recommendations and I went shopping...

I bought MX3660 - 3-Axis DSP Based Digital Stepper Drive Max 60 VDC / 6.0A


SPS487. 48V unregulated power supply

3x SY60STH86-3008B Nema 23 Stepper motors

I also bought the screened cable recommended in another thread and rewired all 3 motors back to the control box. I’ve earthed all cables at the box end and replaced all components. It all fits nicely in my blue box too.

After all of this I have fired her up and she is running perfectly. No more stalling, missed steps, or dodgy inconsistent cuts!!!

Just want to say thanks to all you guys and to Jazz for his kit recommendations. So much smoother, quieter and working well! Now I finally have a machine I am happy to work with at last.

cheers guys. :-)

Got a few questions to ask about my setup to perfect it. But will ask them later. just wanted to let you guys know how it turned out!

thanks andy

Great news and happy your sorted. . :yahoo:

Can't beat good electronics they make a world of differance and don't workout that much more expensive in the grand scheme of things when you consider you only spend the money wounce and they work perfectly so No spending weeks pulling hair.!!

lol ain't that the truth. Sat watching nervously while it did its first test cut after being rebuilt. Phew that was nerve wracking!

Glad I listened to the advice regards new electronics. The bigger motors and the electronics make a HUGE difference with the way its running now.Looking forward to actually making things rather than fixing them lol. Thanks for all the time you guys took for your advice.

andy