Messages

11

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 22, 2022, 07:05:22 PM »

Thanks for the detailed information Craig, also to u Steve, so we can say that microstepping is ideal for cnc machines like laser/plasma/water jet cutters or small machinery like pick and place machines which has light weighted gantries.

In my case the ideal is full step as it seems because i need the full torque from the 16nm motor, x axis motor is driving the heaviest weight in this machine.

Hakan

12

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 22, 2022, 04:54:47 PM »

Hi Graig,

well as manufacturers say smooth motion is the gain of microstepping but the aim is dividing 1 rotation to higher number of pulses which should increase the precision of motion u are getting from the motor/ballscrew. So 1.2 degree motor should receive 300 pulse for 1 full turn but with microstepping u double, triple or increase the pulse number 10 times, the resolution of motion with 300 pulse and 3000 pulse for 1 turn can not be same i think, if u are not loosing steps u are increasing the resolution(precision) of motion u get out of the ballscrew.

If the pitch is 5mm, in 300pulse case u get 0.016mm movement for every pulse and in 3000pulse case u get 0.0016mm movement am i right? or wrong?

U are saying in real world driver can not do 10 times microstepping but if thats the case the drivers should not work and machine wont be able to move as u command but it is moving. for example in that driver there is 30000 pulse microstepping and in that microstep resolution when i command the axis to move 1 microns it moves 1 microns.

Hakan 

13

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 21, 2022, 04:52:05 PM »

Hi,

I decreased the microsteps 1/10 and ran the same code, it finished it without any error. It seems that the problem was high microstepping which lead to high pulse numbers because of the 5mm pitch of ballscrew in small movements(helixes), machine moves very fast in those areas and Mach4+ESS generates very high number of pulses in less than a second which the stepper drives can not accept. The 3 phase 16NM stepper driver accepts max. 200khz signal so when pulse generator exceeds 200khz momentarily, stepper driver looses it.

So the correct approach in microstepping should be adjusting it to a lowest value which is enough for the required movement precision, 2 micron is what i adjusted it for today, before it was very high like below 0.05 microns of electronic precision which the machine can never perform mechanically.

To be sure i need to run at least 10 jobs but it didnt make any absurd movements in 3 jobs i ran today, so thanks to you all for the help and support.

Regards,

Hakan

14

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 20, 2022, 07:18:03 PM »

Hi Steve,

Thanks for the reply, 500.000 step/second is in total for all axises? or per axis?

So u are also suggesting to decrease the micro stepping did i understand correct?

Hakan

15

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 20, 2022, 07:07:38 PM »

Hi,

I didnt say its a general fault of Mach4, i said its something Mach4 is doing because i can see that the zero point in Mach4 has changed after this happens, something is triggering that error in my case, i am trying to find out what it is.

If it were a general error all of u should see it, its not a general error. But its a fact that something is triggering it to happen. and the weird thing is i get all of the gcodes from hsmworks/mach3 post processor and most of them works fine without any error.

u mean instead of g28 it should code g92? I could try that also, its simple to find out if it is the problem, when i ran the code in the air, if it does the same movement in same place than its because of the g28, if its because of the gcode, error should repeat itself right?

Hakan

16

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 20, 2022, 05:13:51 PM »

Hi,

Bob is pmdx-125, yes u are right about ess and mach4 but as it seems this looks like mach4 related to me because its the one which shifts the zero point by 400mm, there is no such command in the gcode, for some reason it suddenly thinks that the axis moved forward by 400mm and tries to fix it, that is what it is doing. For what reason zero point shifts during operation? stalling came to my mind at first also but for that much shifting u have to hear a stalling noise(and u know the noise and oscillation that big steppers does) for about 6-10seconds at least. so its very close to impossible to not to hear/feel it when it happens.
 
Tomorrow i will try decreasing the microsteps , and if that doesnt fix it i can also try to make improvement for stalling, what would be your advice to fix it if we assume X axis stepper stalls(i never heard that noise during operation as i said but lets try it also) i dont want to lower the accel. too much as u know it may lead to loose positional accuracy, what would be your advice for the velocity and accel. values? Its driving 600kg of weight via 40mm diameter 5mm pitch 2000mm long ballscrew.

Hakan

17

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 20, 2022, 04:39:02 PM »

Hi Craig,

I know that thanks for reminding me, X axis has open loop 3 phase stepper, Y axis has closed loop 1.8 degree stepper, z axis has a servo motor, this is a prototype machine to test all types of motors.

This error happens in both open loop stepper(X axis) and closed loop stepper (Y axis) so i dont think its about position feedback, and about missing steps; missing steps is 1 step or 10 steps, i dont think it can be couple million steps. loosing zero point for about 400mm with 100 microstep(30000 pulse/revolution) and 5mm pitch ballscrew u have to loose 2.400.000 steps if i am not mistaken.

About the stalling, motors are not stalling they keep on working normal just the zero point in mach4 is shifting, i am not sure about the open loop 3 phase driver but closed loop driver(fastech ezi-servo https://fastech.co.kr/new/eng/sub0102.php )  has a fault function, it even stops immediately if the axis slightly hit something so it has all kinds of protection for the stall, overload etc. Its a precision product made by koreans, they say its better than servo motor

I can not say for sure but this may be happening when i increase the fro during operation, so closed loop stepper has high micro stepping too, i remember adjusting it as the highest it can get so maybe mach4 and ess can not catch the required pulse number when fro increased. And the reason that it happens time to time may be when both axis make small and sudden movements like small helixes while diving in to part etc. 

sorry for my english, it is rusty little bit but that is what comes to my mind after Graham's advice, what do u say?

Hakan

18

Mach4 General Discussion / Re: dangerous malfunction of a machine driven by Mach4

« on: February 20, 2022, 01:21:37 PM »

Hi,

Thanks for the advice, i will try to reduce the micro stepping, i did that to achieve high resolution for positioning since the ballscrew is capable of doing that. u are right it can overload the pulse generator, will try and run the same code in air.

Hakan

19

Mach4 General Discussion / dangerous malfunction of a machine driven by Mach4

« on: February 20, 2022, 11:24:33 AM »

Hi guys,

I faced with a very dangerous error yesterday while running a gcode in Mach4, in short the problem is; Mach4 looses its zero point while running gcodes, this happens once in a while, like 1 out of 8 jobs. At first it was like missing the zero point in X(generally X, couple times it happened in the Y too) within 40-50mm, i was stopping the code and realign the axis and go on from there, but yesterday it lost the zero point by 400mm!! i was not close to the machine so it went 400mm(approx.) back in -X direction and hit the limit switch so that the machine stopped. (There is a malfunction in the front, +X direction limit switch, i ordered the new one and waiting for it to arrive to change it, so if it moved in the + direction it would not stop by hitting the limit switch and that would kill the machine for sure, this is a c3 ballscrews attached 4 ton machine, so it would cost very much). First thing tomorrow i will attach a small limit switch i have in hand to the +X direction before running the machine again.

But this problem is very weird, most of the code runs normally, i always generate the gcode from Solidworks, HSMworks with Mach3 post processor, so there is nothing wrong with the code(i am posting the code anyway), in general there is no noticeable noise in the machine and if it was noise i think i should get the same error in every gcode i run but this happens once in a while and can not say when actually. Gcode runs normally but suddenly at some point zero point of X moves back to 400mm and machine thinks that it is in the wrong place and moves back to keep up with the coordinate in the code, so it moves in a wrong place. It ruins the part, in addition to that a high quality PCD bit and sdc holder was installed yesterday and just because of the luck it didnt hit to anything while moving to the wrong coordinate. the plate is relatively big so in general i attach other jigs on the plate i was lucky it didnt hit them.

So as you can understand this is a very very serious malfunction for a cnc machine in every aspect.

I searched the web and forums for a similar error and found out that Mach3 users faced with the exact same error before but no one understood why this happened or didnt post any solution about it.

X axis is driven by a 16NM stepper motor, 100 microstep / 30.000 pulse per revolution, (i have a 11NM servo and using the stepper because its more powerful, the Y+Z axis is 600kg in weight approx.) its driving a 40mm diameter, C3, zero backlash, 5mm pitch ballscrew, i also attached the speed, accel. values for you guys to check. My positioning accuracy is within 5microns.

I was using my own screen while this first started, thought that it may happen because of the screen and reinstall Mach4 and ESS plugins with latest stable versions and started to use Mach4 standard screen as is with no modifying on it. The PC motherboard and ram capacity is more than enough for running Mach4, nothing wrong in device manager and all drivers are up to date including the gpu.

Do you guys have any ideas about the reason and solution of this weird problem? anyone faced with the same error while running a gcode? why would Mach4 loose its zero point by 400mm during operation? any ideas are really appreciated, thanks in advance.

Hakan

20

Mach4 General Discussion / Re: surface map

« on: April 28, 2021, 06:45:03 AM »

As i understand from the replies this surface map wizard left faulty like this on purpose and they are not willing to fix it.

Switching to Linux CNC.