6040 CNC strange behavior

[maxime_ecn]

Hi guys, this is my first post here.

I have a chinese 6040 cnc since a year and it started to have a strange behavior, it drives me totally crazy.

My problem is the following :

When i press "start" in Mach3, 3 things can happen :

1 - If i'm lucky, the CNC goes from his actual position to the first position in the program and start machining without any trouble.
2 - The CNC goes from his actual position to the first position in the program but has a kind of "freeze" during the travelling. It freezes for approx 0.5sec and eventually the motors loose a few steps. Here is a video of this problem :



3- If i'm unlucky the CNC goes from his actual position to the first position in the program but has some serious issues to travel there, the motors miss a lot of steps and make an awful grinding noise. Video of this problem :



These problems only occurs in the very first displacement of the CNC, after i click start. When i jog manually, no problem at all. No problem during machining neither.

1 time out of 4 i get the n°3 situation, which drives me crazy because i often do jobs with 4 or 5 tool change and if it happens i loose my X0Y0 reference point.


So first i thought it could be a mechanical problem like friction in the ball screw for example. So i dismantled the 2 motors and checked the mechanical parts, everything runs smooth. Then i tried to start my programm again with the dismantled motors and had the same problem, so it's definitely an electrical or a software problem.


What i did next was playing with the motor tuning. In the 2 first videos i posted, travel speed was set on 1500mm/min and acceleration 200mm/s/s. The manufacturer suggest 2800 & 300.
I realized that the more i decrease the acceleration the less the problem n°3 occurs. At 50mm/s/s i couldn't make it happen again, eventually only situation n°2 occured.
But 50 is slow acceleration, so it increase manufacturing time a lot..

Then i realized something strange. When my motors are tuned at 1500mm/min for example and when i'm jogging manually, in the feedrate window you can read the feedrate unit/min in real time and once the motors have fully accelerated it max out at 1500mm/min as expected.
But when i run my program, the problem occurs at the first displacement, the corresponding line code is "G0 X19.28 Y130.774" in my case. And during this displacement, the speed is not constant at all and max out at more than 1500. Is it normal ? i read somewhere that G0 speed should not be bigger than the value i put in the motor tuning menu..

Here is a video of what happens exactly, pay attention to the real time feed rate :


Finally i tried to change my code line and put : "G1 X19.28 Y130.774 F500." to force my CNC to go at 500mm/min on the first move. But one more time the speed is not constant and faster than 500.. Video proof :




I'm pretty sure that the problem comes from this non constant speed, mach3 is sending bad signals to the motors and when the acceleration is set too high it drives the motor crazy.. That's what i think but i'm a noob so i can't find out myself.

Hopefully somebody here can help me resolve this problem because i don't know what to do... i would like a reliable machine and i'm ready to spend some $$$ to upgrade and fix this if there is no other solution.

Thank you very much

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[joeavaerage]

Hi,
all steppers lose torque the faster they go. It sounds like you are demanding that the steppers spin fast and are therefore at much reduced torque and thereby
stutter and or stall.

Either get better steppers (low inductance being best for high speed ops) and/or better (highsest possible voltage) drivers.

Craig

[maxime_ecn]

Hi,
all steppers lose torque the faster they go. It sounds like you are demanding that the steppers spin fast and are therefore at much reduced torque and thereby
stutter and or stall.

Either get better steppers (low inductance being best for high speed ops) and/or better (highsest possible voltage) drivers.

Craig

Hi, thanks for your answer. You are right but how do you explain that i can jog manually without any problem at 2800mm/min and 200mm/s/s and that the problem appears when i start the program with motor tuning set at 1500mm/min and 100mm/s/s ? I think it's more complicated than that. It's only the very first displacement who seems to make troubles.. after that everything runs smooth

Envoyé de mon SM-G935F en utilisant Tapatalk

[joeavaerage]

Hi,
from your description then you are probaly correct, the fault is not the steppers. What doe the manufacturer say?

Craig

[maxime_ecn]

Hi,
from your description then you are probaly correct, the fault is not the steppers. What doe the manufacturer say?

Craig

They can't help me...


I just opened the control box, pictures are in attachment.

First thing i will try is another version of Mach3 on another computer.
If it doesnt' work maybe i should try to make a better wiring with quality cables before trying anything else.. As you can see nothing is shielded, so this problem can be caused by interferences.

[joeavaerage]

Hi,

They can't help me...

Oh, the joys of buying Chinese.

First thing i will try is another version of Mach3 on another computer.

That might work, the Chinese often supplied doctored (to make it work with their controller) pirate copies of Mach3. To be honest I think
you are clutching at straws. Same goes with shielded wiring, it may help but will not be a panacea.

I would recomend in the first instance replacing the motion control board with a US or European made controller like an Ethernet SmoothStepper
or a UC300. You may have to invest more in steppers/drivers/power supplies later on but at least with an ESS you could be assured your stepper
drivers are getting good pulse streams.

Craig

[maxime_ecn]

Hi,

Oh, the joys of buying Chinese.

Yes so true haha

When i bought it i was still a poor student. Now that i earn a good income i'm willing to upgrade.

When i searched for a distributor for the ESS in my country (Switzerland) i found this company who's making this control unit : Boitier de contrôle pour CNC

Spec :

Max current 3A, adjustable.
4-axis power card with Toshiba TB6560AHQ power module.
Step modes: 1/1, 1/2, 1/8, 1/16.
Optically isolated parallel port.
Extension inputs and outputs available.
Relay available, for example for automatic watering control.
Compatible with MACH3, EMC, KCAM, Galaad (with specific USB interface module)
Power supply 24V 350W 12.5A.
12V 10W 1A power supply for lighting.
230V input with network filter.
Optional USB or Ethernet interface available.

Ethernet SmoothStepper is in option. Total price for the complete box is 830$. That's expensive (Switzerland hourly cost is really high) but i'm so tired of having problems and i need to resolve them fast. At this price i will also get a decent after sale service.. what do you think ? is it worth investing?

[joeavaerage]

Hi,
looking at the photos it appears that it has an ESS in the heart of the machine.

An ESS direct from the manufacturer is $180USD. Do you believe that box of goodies adds value to $830???

Your after sales service is a bit of a problem. I imagine the Swiss manufacuturer will help you with the box ot stuff, but they don't make the ESS, that comes
from the US, and so that part, and in my opinion the critical part, its after sales service will come from the US also.

It still looks like a major step in the right direction, and supporting local business is worthwhile.

Craig

[ZASto]

Ha, chinese components assembled in CH
At least stepper drivers

If you want to make your own control box, you could takr in consideration PureLogic PLCM-E3 external controller with PLCM-B1 BOB. Accompanying software is Pumotix. Europian made (Russia).

[Sterob]

They can't help me...


I just opened the control box, pictures are in attachment.

First thing i will try is another version of Mach3 on another computer.
If it doesnt' work maybe i should try to make a better wiring with quality cables before trying anything else.. As you can see nothing is shielded, so this problem can be caused by interferences.

A couple of things I noticed....
Your Control Board is right next to your power supply. That increases your chance of EMI causing problems and probably nothing you can do about it without a major re-work.
Also the centre Stepper Driver wiring is different to the other 2. No expert,just an obserrvation....

Have you checked all your terminations by gently tugging and tighness of the screws? make sure all plugs are 'home' properly.

[ericks]

I would expect emi issues due to some wiring issues there...

[maxime_ecn]

Thank you very much for your help guys. Yesterday i reinstalled mach3 on another computer (my asus Laptop). This morning i tried again and all my problems are gone.. so maybe it was interferences from computer, or from the chinese version of Mach 3... But i'm happy that i had all these problems because this past week i learned a lot of stuff thanks to you and the forum research i made.

I'm happy that my machine works again but to anticipate future problem i decide to make another control box, because the one i have is obviously a piece of crap ^^

Thanks again

[ericks]

Thank you very much for your help guys. Yesterday i reinstalled mach3 on another computer (my asus Laptop). This morning i tried again and all my problems are gone.. so maybe it was interferences from computer, or from the chinese version of Mach 3... But i'm happy that i had all these problems because this past week i learned a lot of stuff thanks to you and the forum research i made.

I'm happy that my machine works again but to anticipate future problem i decide to make another control box, because the one i have is obviously a piece of crap ^^

Thanks again

Glad you got it sorted

[Sterob]

Glad you got it sorted.
Well done.

[joeavaerage]

Hi,
good news that you have got a working solution.

I would commend you consider as a medium term project upgrading the controller.

The motion controller is the heart of the machine, any deficiency there will show up as poor work or interrupted part
programs. Converslely a good controller will quietly go about its work without you having to think (unduly) about it
and you'll have it for years and years.

I'm biased, so please take my recommendation in that context, but the Ethernet SmoothStepper has proven to me to be
that 'good as gold' controller. Note also that I use Mach4, and have done since switching from Mach3 five years ago.
All development on Mach3 ceased six years ago.

Both Mach3 and Mach4 have a Modbus feature.I have used the Mach3 version and got it to work but swore 'never again'. The
Mach4 version is like night and day, you can set up mutiple Modbus channels in the time it might take to get one with Mach3.
This is just one area, as an example, where the features of Mach4 exceed Mach3.

Craig

[mactec54]

They can't help me...


I just opened the control box, pictures are in attachment.

First thing i will try is another version of Mach3 on another computer.
If it doesnt' work maybe i should try to make a better wiring with quality cables before trying anything else.. As you can see nothing is shielded, so this problem can be caused by interferences.

Run some new main Ground wires most of these are not Grounded correctly, so you may have a noise problem, I would also lower the velocity and see if it changes anything 1500 is the correct setting for this machine

Reinstall Mach3 could help but changing the software is not going to solve this, do you have a dedicated computer with not internet connected Etc ???

Check the spindle Ground

[maxime_ecn]

Hi,
good news that you have got a working solution.

I would commend you consider as a medium term project upgrading the controller.

The motion controller is the heart of the machine, any deficiency there will show up as poor work or interrupted part
programs. Converslely a good controller will quietly go about its work without you having to think (unduly) about it
and you'll have it for years and years.

I'm biased, so please take my recommendation in that context, but the Ethernet SmoothStepper has proven to me to be
that 'good as gold' controller. Note also that I use Mach4, and have done since switching from Mach3 five years ago.
All development on Mach3 ceased six years ago.

Both Mach3 and Mach4 have a Modbus feature.I have used the Mach3 version and got it to work but swore 'never again'. The
Mach4 version is like night and day, you can set up mutiple Modbus channels in the time it might take to get one with Mach3.
This is just one area, as an example, where the features of Mach4 exceed Mach3.

Craig

Thanks man, i will definitely use the ESS for my futur control box

Run some new main Ground wires most of these are not Grounded correctly, so you may have a noise problem, I would also lower the velocity and see if it changes anything 1500 is the correct setting for this machine

Reinstall Mach3 could help but changing the software is not going to solve this, do you have a dedicated computer with not internet connected Etc ???

Check the spindle Ground

I swear the problem was from the computer, since i switched to my laptop everything is running smooth without any problem. Now the laptop i'm using is my everyday laptop, so i have internet connected etc.. i know it's not the best but it works flawlessly..

[mactec54]

Thanks man, i will definitely use the ESS for my futur control box





I swear the problem was from the computer, since i switched to my laptop everything is running smooth without any problem. Now the laptop i'm using is my everyday laptop, so i have internet connected etc.. i know it's not the best but it works flawlessly..

That could be, your lap top has an isolated power supply this can make all the difference between the 2 computers but most likely the computer you where using was not suitable for CNC use, there are many computers that don't perform very well for CNC Control use