knocking noise from Z axis stepper motor

Hi,

My Z axis having noise problem since day 1 , I changed a new M5 rod and nut that bought locally, new Z gear and new Z driven gear, new bearing for Z drive gear, and problem remains. I noticed that every time when I switch on the Ormerod , the very first 5 or 10 minutes it run smoothly, but after 10 minutes and the knocking sound starts from Z stepper motor.
I try to remove both Z gear / driven gear , just let the stepper motor unload, and I lightly hold the motor shaft, I can feel that motor vibrating / knocking internally . Already contact support and still wait for reply.
Anyone here having the same problem ?

Take the motor apart and clean it out with air, there may be small pieces of metal grit inside left from production, haven't done it myself but to take the motor apart and clean it out should be no problem according to Ian from RepRappro support

Edit: If you do take the motor apart a few pictures of the inside parts would be nice

Erik

Edited 1 time(s). Last edit at 02/02/2014 05:39AM by ormerod168.

Hi Erik,


I'm thinking of doing so, but a little worry if I can't fix it, and support might not accept it for warranty. I'm in Asia country, replacement motor will take ages to arrive here. If support agree to let me open it up, I will be happy to do so.


Ew

Quote
tru168
Hi Erik,


I'm thinking of doing so, but a little worry if I can't fix it, and support might not accept it for warranty. I'm in Asia country, replacement motor will take ages to arrive here. If support agree to let me open it up, I will be happy to do so.


Ew

Don't worry they will, it's no big deal to dismantle the motor, should be quite simple according to Ian, has been discussed here before, afair Ian said no problem with warranty as long as you use your common sense and don't beat it with big hammers

Don't worry, you can do it!

the topic about it is here somewhere, did a search but did not find it, sorry
------------------------
..comes to think of it, me better work the work than talk so here's a picture of the filament motor I just took down, nothing to it, the wiring is quite thick, is low voltage, notice how small pieces of grit, if it gets between the rotor and stator easily can stop the motor from turning, there is nothing to it, go for it!



Erik

Hint: when you put the end parts on again, arrest the disc and spring disc with a bit of grease so they stay down until the bearing reach its end point

The end pars should be allowed to slip on freely, don't try to force one side only, should go on easily in a parallel way



when you have tightened the four motor screws, give the ends a small sharp jab with something light as to make the bearings float free and center against the spring disc

Mine i back together again - it's alive! - it's alive

Erik

Thanks Erik for the detail. I will do that and post the result here later. Thanks !

Just swapped the extruder motor with Z axis motor, the problem remains! Duet board sent bad pulses to the Z stepper motor. I also noticed that when I print faster speed like 40mm/s with travel speed of 200mm/s , ALL X. Y and Z axis motor also having knocking noise ! been printed about 800grams of filaments so far and some of them are really in bad shape just because of this problem.
Since I'm in Malaysia , sending it back for replacement will be quite a long while to receive a new one, but I have no choice, its beyond my ability to repair the faulty board and what can I do now is just wait for further instructions from support.

Ew

Edited 1 time(s). Last edit at 02/02/2014 10:59PM by tru168.

Just to confirm that I experience the same knocking noise that I have been unable to track down - the bearings and threaded rod are all concentric. I will investigate further.

Dave
(#106)

not sure if it's the same "knocking" but here goes:
when z-gears turn "more than just a fraction of a turn" i do sometimes get regular "knocking" sounds.
lifting the z-leadscrew and turning the gear a few teeth can make the sound "nearly dissapear"

My experience:

Ticking of the motor could be or bad pulses forcing too high speed, or mechanical resistance.
Bad pulses could of course come from electronics but also from some errors in your g-code file forcing too high speed. If the error is in the g-code file then you should see the problem always in the same spot.


My guess: mechanical resistance!
Check anything which could influence the Z-movement (cable, filament, scrtew thread etc)
I changed the Z-gear myself sice the original had too much play (hole was approx 5.2 mm so I printed a new one which fits great)
Such play would not create the symptones you describe. At least I would recommend to grease the M5 screw lead with some teflon spray and check if it turns better. Testing can be done simple by moving up and down in the suspected area at high speed, try different start-stop positions

Good luck

Try this to see if its the same problem as mine. hold the X axis assembly high and remove threaded rod, remove both Z gear to unload the motor( careful not to drop the whole X axis assembly ) enter command G1 Z100 and let the stepper spin, and lightly hold the motor shaft, you can feel knocking vibration in the motor, thats what I have now. If the stepper motor spinning slower while printing , the sound disappeared, print fast sand it began to vibrate again.
when printing fast, I have Z or X axis sometimes sounds like stuck, and sound like missed step , but the print sometimes looks ok, but sometimes missed step even my belt already real tight.

Hi Marc van Beelen ,


In my situation, thats not mechanical resistance, I unload the motor for test, just lightly hold the motor shaft to feel the vibration. as for bad G code, I'm not running any code yet, just send homing instruction and it began to knock. I send G1 Z100 without any load on the shaft and it still knocking. I did swap stepper motor and problem remains.


I will try to see if I can take a video clip with enough microphone gain to pickup the noise , and share it on youtube so that everyone can see if its the same problem .

Edited 1 time(s). Last edit at 02/03/2014 10:47AM by tru168.

Just a idea, to make sure the step motor is OK I would do this:

Take the motor apart, take a good look at the rotor/stator to see if there is any sign of wear between those parts, they are not supposed to touch each other whilst turning, paint the rotor with a thin layer of paint (use a permanent ink pen or whatever it's called in engrish), put the motor together again, important: run the motor with sideway pressure on the drive shaft from all sides, take it apart again and look closely at the ink for sign of contact - and of cause give the inside parts a good blow of high pressure air, there may be small parts inside that you will not be able to see with the naked eye

Erik

OK, thanks for the feedback,

did you try changing the cable to the motor?

I didn't change the cable yet, but I did check carefully all pins in the pin holder, I know sockets will loosen and spark / and fail for some times. and Erik, I swap motors and the problem remains in the same Z axis, I bet its not the stepper that giving me problem. it turns freely when its not power up, and I did take apart and clean the Z motor , which is my extruder motor now.

Quote
tru168
.... enter command G1 Z100 and let the stepper spin, and lightly hold the motor shaft, you can feel knocking vibration in the motor....

Just tried it, my Z-motor runs smoothly with a spinning sound all the way up to max momentum where it of cause start missing steps (holding the gear with fingers) with a knocking sound

..and you should not be able to stop the motor from turning while holding the motor shaft with two fingers (I can't anyway) and there should be no knocking sound at all before the motor starts missing steps

Erik

Hi ormerod168 ,

Looks like yours are good, I lightly hold the motor shaft and I can feel knocking vibration from the motor. since I'm still waiting for support to reply, I bought some wires and sockets and I will change the wire from the motor to Duet and see if it cure the problem. chances are low though, because my motor problem will occur only when I switch on my ormerod for 5 minutes. don't know if thats the stepper motor driver that give problems. I bet even support and crew scratching their head now .
i

Edited 2 time(s). Last edit at 02/03/2014 09:16PM by tru168.

No luck yet, I changed new wires / sockets and problem remains.

Edited 1 time(s). Last edit at 02/04/2014 01:04AM by tru168.

I noticed that when the duet board heat up a little , switch on around 5 minutes, the problem starts. most obvious one will be Z axis, and X and Y axis will click once or twice during print. I have no choice and decided to bite the bullet.
I inspect the board , every thing looks OK, then I apply flux on all 4 pcs of A4982, turn on my hot air blower and reflow the 4 chipset. That cure the problem that I've been frustrated for so long. Finally !
Now I can print again, and I noticed a new problem , I think its bug or something related to firmware. When I run M556 S78 X-0.05 Y-0.4 Z-0.6 command in setbed.g to correct angle shift , I still can hear some minor knocking sound when I send G1 Z50 to raise the Z axis.. it run smoothly/ quietly without loading the M556 angle shift correction command.
Just wish to confirm that was just mine having this bug , or everyone having the same problem, anyone here can you please move your Z axis before M556 command in setbed, and after M556 command and listen to Z axis movement ?

Edited 1 time(s). Last edit at 02/04/2014 08:06AM by tru168.

Quote
tru168
Now I can print again, and I noticed a new problem , I think its bug or something related to firmware. When I run M556 S78 X-0.05 Y-0.4 Z-0.6 command in setbed.g to correct angle shift , I still can hear some minor knocking sound when I send G1 Z50 to raise the Z axis.. it run smoothly/ quietly without loading the M556 angle shift correction command.

I'm not surprised. The current firmware is unable to do combined XYZ or XZ or YZ movements properly. I understand Adrian Bower is working on this. There is an update in the Duet branch of the firmware, with a comment saying that it is still buggy and should not be used. I suspect the knocking sound is caused by the firmware trying to step the z-motor too quickly.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

First post here.

Built my green Ormerod last week, commissioned ok! test pieces ok! network and USB connections ok. Latest std firmware.

Was about to start to run some sliced prints but noticed that the extruder motor is knocking/missing steps even at 200c and run manually. Seems fine rotated when motors off so nothing mechanical restricting the passage of the filament. Standard filament as supplied with the kit. Increased extruder motor power to 1000, but still misses steps when running any prog file and jogging extruder.

Ran a search on the forum and found this thread, but can't find a solution. Any advice or ideas? Not had time yet to swap a couple of motors.


John.

The extruder motor will miss steps on the first layer if the print head is too close to the bed. Probably your z-homing or auto-bed levelling isn't working consistently. Just before you do a print, do a G0 X100 Y100, then a G0 Z0 and see if the head really is just above the bed but not being supported by the nozzle

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for replying.

I think you are correct as the bed leveling is a bit flakey!

Didn't think I was going to get chance tonight to test but managed to grab an hour and reset the bed with manual measurements and checked as you suggested in the centre of the platen, which was fine.

Just started running the ortho align piece which seems to be going really well with a good finish.

Cheers,

Quote
dc42

Quote
tru168
Now I can print again, and I noticed a new problem , I think its bug or something related to firmware. When I run M556 S78 X-0.05 Y-0.4 Z-0.6 command in setbed.g to correct angle shift , I still can hear some minor knocking sound when I send G1 Z50 to raise the Z axis.. it run smoothly/ quietly without loading the M556 angle shift correction command.

I'm not surprised. The current firmware is unable to do combined XYZ or XZ or YZ movements properly. I understand Adrian Bower is working on this. There is an update in the Duet branch of the firmware, with a comment saying that it is still buggy and should not be used. I suspect the knocking sound is caused by the firmware trying to step the z-motor too quickly.

He's not doing an XYZ movement, he is setting the axis compensation which does not involve any movement (and should have all parameters on one line). He hears the noise after sending G1 Z50 after axis compensation is set, which ought to work fine. I wonder whether the noise is coming from the X or Y motors in that case - because the only difference should be that a Z move could also cause an X and/or Y move after compensation has been applied, but not before?

Dave
(#106)

Hi,
Yah, my axis making noise by moving x or y axis, and also z axis , the noise from z axis stepper motor. I found that was caused by compansation setting after I do Omanis prints and set the setbed.g if I run my Ormerod without setbed.g , everything goes smooth. Now I try to mod my print bed and try to level the bed mechanically without any compansation / setbed.g.

Quote
dmould
He's not doing an XYZ movement, he is setting the axis compensation which does not involve any movement (and should have all parameters on one line). He hears the noise after sending G1 Z50 after axis compensation is set, which ought to work fine. I wonder whether the noise is coming from the X or Y motors in that case - because the only difference should be that a Z move could also cause an X and/or Y move after compensation has been applied, but not before?

If he's got nonzero axis compensation set, then he is doing a combined XYZ movement even when he's only asking for an XY or Z movement. The current firmware does seem able to cope with small amounts of compensation. I recommend ensuring that the Z axis is truly perpendicular to the Y axis, levelling the bed manually as far as possible, then using the auto compensation (if it is working reliably for you) as a fine correction.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42

Quote
dmould
He's not doing an XYZ movement, he is setting the axis compensation which does not involve any movement (and should have all parameters on one line). He hears the noise after sending G1 Z50 after axis compensation is set, which ought to work fine. I wonder whether the noise is coming from the X or Y motors in that case - because the only difference should be that a Z move could also cause an X and/or Y move after compensation has been applied, but not before?

If he's got nonzero axis compensation set, then he is doing a combined XYZ movement even when he's only asking for an XY or Z movement. The current firmware does seem able to cope with small amounts of compensation. I recommend ensuring that the Z axis is truly perpendicular to the Y axis, levelling the bed manually as far as possible, then using the auto compensation (if it is working reliably for you) as a fine correction.

So you are saying that the firmware cannot cope with its own internally generated XYZ movements due to axis compensation either? It certainly appears to work fine for bed compensation - the Z is up and down like a fiddler's elbow during XY moves on my machine. My axis compensation is extremely small, so I probably would not see any adverse effects from those Z moves.

Dave
(#106)

The firmware copes with internally-generated XYZ movements when the amount of correction is small, so you have either an XY move with a very small amount of Z, or a Z move with a very small amount of XY. Maybe the Y-0.4 correction he is making is too large for it to handle well. I'll take a look later in the week.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
The firmware copes with internally-generated XYZ movements when the amount of correction is small, so you have either an XY move with a very small amount of Z, or a Z move with a very small amount of XY. Maybe the Y-0.4 correction he is making is too large for it to handle well. I'll take a look later in the week.

I think you have just cleared up a mystery for me. I do the Z-height and bed compensation by hand for every print. Without having yet done any bed modifications, my bed compensation changes between about a 0.4mm max difference and a 1mm max difference between prints thanks to the MDF. I have wondered why I sometimes hear a knocking sound and sometimes not from the Z axis. That may well be the reason!

I really must take the time to fix up my bed.

Dave
(#106)

I can confirm the knocking noise issue. following facts are repeatable and double checked

- before sending M556 S74 X-0.6 Y0.0 Z-1.2 all is fine
- after sending M556 S74 X-0.6 Y0.0 Z-1.2 the noise is here
- after changing the M556 values the ryhthm/noise is changing
- after reset all is fine

it is only the Z-axis
- when changing the Z-wire to the Y-stepper the noise comes from the Y-stepper...

it doesnt matter if sending via webinterface or do the setbed.g with the code inside

so - how to do the "M556: Axis compensation" without knocking noise?

Edited 1 time(s). Last edit at 04/17/2014 03:25PM by FastFlyingFox.