Unresolved Motor noise after a bit of running

Hey guys so I notice that after a bit of time running a print my stepper motors start to make some noise, I am pretty sure it is coming from the X axis stepper. The motor is fairly hot to the touch, wondering if I need to look at adjusting the POTs? (kinda afraid to mess anything up since I am finally rid of my z ribbing lol)

It hasn't caused any issues yet that I'm aware of but I feel it is adding harmonics to my prints and want to try to remove it. Plus when it does a rapid move it can be very loud.

Here is a video, it can be a bit difficult to hear it in the background over the fan but it has a grinding noise to it.

Wikid

 

If I lower it slightly to keep it a bit cooler, will it affect prints ie do i need to adjust jerk or accel after doing so?

I am getting some vertical lines on round prints and printed some herringbone gears and on the tip of the teeth look like a change of direction artifact. would lowering the Pot to the X axis cause this issue to be exaggerated due to reduced current?

Wikid

 

you could have z scarring, google image search it.

Before you turn the POT I would record the reference voltage between the center of the POT and the ground pin on the stepper driver. This way if you screw it up you know where to go back to.

 

Ill look into adjusting them after I get back from class. Here is some pictures of what I am talking about, if you look at the edge of one of the teeth just as it comes around the tip it dips in before finishing the rest of the tooth. Then in the Z axis direction all around the round portion there are in and out bumps, like facets.

As for the sound it comes and goes but sounds like the bearings grinding in the X axis.

If you can, could you please throw up a picture of where reference voltage and ground pins are on this board unless they are clearly marked.




Wikid

 

With google image this is the best I could find.

https://a.pololu-files.com/picture/0J3360.600.png?d94ef1356fab28463db67ff0619afadf

 

There was an unofficially reported bad batch of bearings and rods. Are there any scratches on your rods? A bad bearing is not going to magically go away.

 

Thanks mike that really helps out, gonna save that picture!

Stephen when you say bad bearing and rods are you referring to the linear rods and bearings?
The rods are perfect, it could be bad bearings but the noise defiantly comes from the motor.

The surface finish I think it related to something else because the finish is like that on the circumfance of the part not just the side where the x moves the most

Wikid

 

it could also be a low resolution model. STLs can be created with a varying number of triangles.

 

Also true Stephen but I tried it with my test circle which was created in Solidworks and set the stl output to the highest resolution possible. Solidworks can output AMF files but not sure how much of a difference it would be versus STL. Haven't looked into it. Would be nice if it could slice the solid model than a bunch of triangles. Which could only be an issue for CNC machines and not a 3d printer.

Wikid

 

So I adjusted the X from 416mV to 300mV on the reference. The Y axis was at 385, I left it alone. The Y axis seems easier to force it to skip a step than the X. The X is still very strong at trying to get it to skip takes a bit of work, to the point that the machine slides on my table before skipping. The sound is still there, I am wondering if it might be a bad set of linear bearings in the X carriage, is there a higher quality set available or should I try to get a replacement from Robo3d?

I can feel the roughness in the carriage when moving it by hand, and that's with the belt removed I also notice from time to time moving it that it will hit a hard spot moving.

Wikid

 

Definatly under warrenty, im talking to them about it also see what they suggest. I ended up bumping the pot up a little on the y axis also since it seemed a bit weak.

I am also trying to find some info on fixing the change of direction and start stop bumps i get in parts. The extruder is calibrated but the start and stop in the same place for the next Z level i end up with a blob there.

 

Really.... what is it and how do i change it? I am using Cura if that makes a difference

I think one blob comes from the "stop move up in z then go" and another comes from finishing the outside layer stopping then going to the inside or fill area.

 

Simplify looks to be very handy and may end up getting it, I have gotten used to Cura. I am trying to find if it is capable but it looks like many requests for a random layers start have been done but this version does not have it.

I am looking to see if I can get it to retract when moving from the wall to the inner portion