(Solved) Vibration toward the back of the bed

[Burcadus 0]

Hi everybody,

 

Usually I find the solutions for my troubles by searching on the web. But, on that specific case, I don't see anything similar... So :

 

See attached pictures, you will notice that the print is ok on one side but very ugly on the other. Being a Fabmanager wasn't there when that print was sent. I tried to print a cube to see if the trouble is reproductible. Yes it is! The bed is shaking but only when the head moves in the y axis and it get worse when the head is closer to the back of the printer (I call the back the side of the printer where the Z lead screw is).

 

I tried :

- leveling the bed (many many times)

- adding more tension to the spring of the bed in order for them to be stiffer

- increasing the extruder temperature (I even went to 230C!)

- printing the cube with no filament (to see if the vibration is still there; kind of air guitar!) : less vibration but a noise.

 

Any advice will be very appreciated.

 

 

[geert_2 557]

Did you check if the rods are well oiled? With the printer off, if you move the head by hand, it should move reasonably smoothly in all directions. At least, if it is an Ultimaker; I don't know about other brands with other drive mechanisms.

 

If it would only be a visual effect, without mechanical shaking (especially in an Ultimaker2), it could be caused by a tight bending radius of the filament (e.g. near the end of the spool), causing a lot of friction in the nozzle and bowden tube, and thus causing underextrusion?

 

[Burcadus 0]

Hi Geert,

 

Thanks for taking the time to look at my case!

 

Of course, my printer is an Ultimaker (2+ Ext). For a short while, I thought that a ball bearing might be broken but, I think there is no ball bearing on that shaft, only a brass sleeve. I just lubricated the shaft (using the grease supplied with the machine) and slided it many times (with the power turned off). Then I tried another print and got the same vibration.

 

With the power turned off, I moved the extruder and felt the vibration and hear a noise. I think it comes from the bearing but that's difficult to be sure. Could it be a stepper motor?

 

We own two identical Ultimakers,  of course the second one don't vibrate and make no sound while the extruder is moving toward the y axis.

 

I'll make another print attempt placing the cube somewhere else on the bed to determine if the same vibration will occur...

 

Best regards

[Burcadus 0]

So! Just did two other tests :

I tried to print a cube located near the back of the printer and another one located toward the front of the machine. I got the same result for both tests.

 

 

Regardless where the part is located on the plate, the vibration is much more important when printing the side of the part that faces the back of the printer. Not sure I'm clear! See picture below. The square is the cube being printed, the other square with rounded corners is the skirt. Also note the vibration isn't important when the head travels in diagonally.

 

 

I am totally mystified! I can't see how the vibration would only affect the print while the head is moving on the side that is near the back of the printer regardless the position of the print on the plate. One thing I'm almost sure : the trouble seems to be mechanical because the noise can be heard with the power turned off.

 

 

[P3D 46]

7 hours ago, Burcadus said:

Hi Geert,

 

Thanks for taking the time to look at my case!

 

Of course, my printer is an Ultimaker (2+ Ext). For a short while, I thought that a ball bearing might be broken but, I think there is no ball bearing on that shaft, only a brass sleeve. I just lubricated the shaft (using the grease supplied with the machine) and slided it many times (with the power turned off). Then I tried another print and got the same vibration.

 

With the power turned off, I moved the extruder and felt the vibration and hear a noise. I think it comes from the bearing but that's difficult to be sure. Could it be a stepper motor?

 

We own two identical Ultimakers,  of course the second one don't vibrate and make no sound while the extruder is moving toward the y axis.

 

I'll make another print attempt placing the cube somewhere else on the bed to determine if the same vibration will occur...

 

Best regards

 

Grease? I don't know about the UM2, but with the UM S5, there comes a grease which is only to be used for the Z axis, and some kind of oil which is for the X/Y/Z shafts... it says specifically that you should never use the grease for the shafts, only for the Z axis screw.

 

Edit: It is the same for the UM2, see this link: https://ultimaker.com/en/resources/18780-lubricate-the-axles

Edited December 14, 2018 by P3D

[geert_2 557]

11 hours ago, Burcadus said:

...

I just lubricated the shaft (using the grease supplied with the machine) and slided it many times (with the power turned off). Then I tried another print and got the same vibration.

...

 

The grease is for the Z-screw only, not for the X- and Y-rods, nor the Z-rods.

 

The Z-rods need no oil at all, if I understood well, since they have linear recirculating ball bearings inside (I don't know the proper English term).

 

The X- and Y-rods need some light oil, like for bikes or sewing machines (but not dislodging oil, thus no WD-40 or similar). Although I use an hydraulic oil for fine hydraulic machines, because I have plenty of it in spare, and it does not dry out at all, and it lubricates well. I found that the sewing machine oil I first tried, dried out too soon into a sticky layer.

 

But that doesn't explain vibrations at the rear side of the model only, when the model is sitting in front of the printer, indeed. Or do the vibrations only occur when traveling from left to right, and not from right to left (or vice-versa)? So there would only be stuttering in one direction? I would try to further diagnose by manually moving the nozzle, with the printer off.

 

[Burcadus 0]

Thanks P3D... Didn't know...

 

I wiped what I can...

[Burcadus 0]

Just checked : vibrations seems to be the same regardless if the head is going to the left or the right.

 

I think the noise comes from the stepper that is in the upper right corner. I might unassemble it next week. Here I have some other similar steppers (for a Reprap project), I'll try to replace it. On that topic : should I check for a particular quality or specific features? I'll do that this afternoon or next week. I'll keep you informed.

 

Best regards

[Burcadus 0]

Solved! It was a broken stepper : it was vibrating only when turning in one direction. I replaced the part and our printer is operationnal again.

 

Thanks Geert_2 and P3D for your help!