y belt position / loud y axis

hey all,

where should the y belt be seated on the end opposite the stepper motor / pulley. I’m sorry I do not know the name of the cylindrical / smooth part that the belt wraps around opposite the stepper motor :frowning:

should the belt be seated at the bottom of that part, rubbing the abs bracket?

also, my y axis is very loud as it travels towards the stepper motor. it seems as if its rubbing against something. maybe the bushings need to be “press fit” (squeezed) as i’ve read in a different thread? maybe this sound is normal? i really don’t have anything to benchmark this noise against.

also, would the dev file be the best place to learn all the technical names of the printer’s parts, and match those names up with drawings? does a CAD file exist that has all the printers parts, possibly marked up?


slightly unrelated edit:

ought my X belt be rubbing against the tension screw (closest to the x stepper motor)? And how might one gauge the correct tension of the x and y belts?

my Y belt is setting exactly in the middle of the far end idler pulleys. I had to make a hardware modification to my X axis belt an idler pulleys or my belt would slip off. After that mod, my X is the same as my Y, the bet rides in the middle of the 2 stacked bearings (pulleys).

Not sure I’ve heard this noise on the Z axis, but I only had mine functional for a few days until the bed had a problem and needed to go back… I’ll keep an eye on that.

On the X axis pulley, you can move the gear drive on the motor in and our and the belt in the belt holder clamps to get the belt away from that screw and it sounds like you’ll need to do that (one or both).


The Y axis belt should be roughly centered around the two bearings. The dual idler bearings should be self centering. If not the belt may need to be raised by lifting on the belt near the bearing and moving the bed back and forth. If the belt moves down and continues to ride against the bottom of the idler assembly you can raise the positioning of the belt within the belt clamp underneath the bed.

My Y axis is a bit louder as well and has not impacted the print quality.

In this directory: http://download.lulzbot.com/TAZ/hardware/printed_parts/ you will find the printed parts. In each folder there is a pdf of the part rendering. Hopefully that will help you identify the individual parts.

The screws used on the belt clamps on the X axis should not be touching the belt, you may want to tighten that screw to raise it off the belt. Would you mind taking a picture and sending it to support@lulzbot.com?

The belts should be about as tight as a rubber band stretched around your finger. You should be able to feel a tight resistance and still be able to deflect the belt a little bit. If the belt is too tight it can cause issues and resistance yet it still needs to be tight enough to be consistent.

Here are some snapshots of my x axis from the back


In pictures 5-6 i moved the belt towards the hot end side of the machine, moving the belt’s teeth off the screw heads. However the belt’s side still rubs the head of the screw.

I have to say that I’m psyched about the printer and am getting great prints off the machine. I’m just worried about wearing down my belt :stuck_out_tongue:

I made a FreeCAD assembly file during the TAZ development (when it was still named TK-0). It’s a little outdated now because the Lulzbot guys made some changes on printed parts since I modeled it, also it is not complete but it can give you an idea.


Look for TK0_Assembly.fcstd. All the other files are the parametric printed parts.

FreeCAD is an open source parametric 3D CAD software available on Windows, Mac OS X and Linux. Although the Mac version is not as up to date and suffers from specific bugs.

All the parts in the assembly are labeled.

You may want to loosen one of the set screws on the X axis pulley and move the pulley 3-4 mm away from the stepper motor. Then tighten the stepper motor pulley. Loosen the belt clamp nearest the x axis stepper motor and move the belt end closer to the extruder and away from the screw. Move the x axis back and forth to make sure that everything is moving smoothly and without binding. Try a test print to see if it’s stable and the that belt stays on track.