Guide rods not perpendicular?

I have been observing my M200 during the last few prints in order to determine the source of lots of clicking and popping sounds coming from printer during printing.  I can not quite figure out the source of these sounds.  Some of them are very soft faint clicks while others are much louder, more like a loud pop.  Anyway, while looking around the machine I noticed the two sets of parallel guide rods that the extruder rides on are not square with the machine.  While looking down from the top of the machine it appears that the rods that carry the extruder side to side ( x axis I believe ) are not exactly perpendicular to the rods that carry the extruder forward and back ( y axis? ).  Any ideas if this could be why the machine seems to make all the popping sounds?  It also seems as though I can't get the nice smooth surfaces I was getting with my first prints when the machine was brand new.  Can I adjust these rods to make them perpendicular again?  I have already removed the grub screws on the motor pulleys and tightened them with Loctite, and this helped with some other problems I was having.

Any suggestions would be appreciated.


Can you post a pic? The way the x/y is designed it should bind like crazy if it is not perpendicular.

I was able to fix the misalignment of the x axis.  It was indeed slightly off of perpendicular.  Sorry I had the problem fixed before taking pictures.  All I can say is now I am extremely pleased with this machine.  My surface quality is amazing now.  Also, all of the clicking and popping and grinding noises are completely gone.  Another thing, there is no more high pitch vibration noise on rapid movements that I know a few people have experienced with their M200's.  And now with the new Z-Suite update, I am more pleased all the time.

How did you fix the problem?

I loosened the center screw on one of the black blocks at one end of the x axis. Then while holding the other end of the axis still I was able to just move the end I loosened a small distance which brought the axis perpendicular, at least as far as I can tell by "eyeballing" it anyway.  I don't know if that made sense but that is the best way I can describe it.  Essentially I allowed the end of the x axis to skip over a few grooves in the belt which repositioned it to where I needed it. 

Very helpful in directing my attention to this. My machine as well was out of square after a quick look. The Y-axis bars were off .167" and the X-asis .053". I loosened all four connections and realigned the assembly square with the bed and housing. I would think this alone could solve dimensional problems and what I suspect were friction noises I was experiencing since its purchase about five weeks ago.

This worked for me as well. The gantry was extremely hard to move in the X-axis and the printer in general was very noisy compared to the other M200s I have. I loosened the screws on the front black block enough that the belt slipped a tooth or two and now it prints quieter and the x-axis moves much easier (powered off of course). I only noticed how tough the gantry was to move because you need to move it to gain access to the grub screws for tightening.  Cheers!

Good day all,

Just a short question. How do you all measure if the gantry is 90 degrees to each other ? Do you simply use a digital protractor or the diagonal method commonly used in CNC machines where you mark the four " max "corners of the work plane and measure them ? Please assist. Thank you.

Best Regards,


Eddie ~ For me, I didn't actually measure it and it wasn't visually apparent but once I loosened the two hex screws in the middle of the black block and the belt slipped a bit, you could see the tension was removed from the gantry. I then tightened the screws and manually moved the gantry with my hand and it was no longer hard to move and no longer as noisy during printing. -David

Thank you David for your prompt reply. Unnecessary tension does imply that the gantry is not well squared. I am not too sure if my printing is considered noisy or not.

For my situation, the black box part ( the part that holds the belts and rails together) has developed a crack that Zortrax support team was efficient to send me some new ones to replace them. Thanks support.

However my concern is that if I were to remove the broken parts will the previously calibrated position be lost ? I understand that there isnt any encoder on the system.

On the other note, I can never get the print bed to level to 0,0,0,0. It is always a weird combination of some max -0.2 and +0.2 somewhere. I have taken all the steps displayed on the support web page to maintain the pef board but show no avail. Is there a slim possibility that the Z-table isnt completely flat ( the part that is connected to the 2 columns and Z-screw) ?

Any insight will be awesome. Thanks again.

Best Regards,


I would think that the metal build platform is pretty flat, but the perfboard assembly almost certainly isn't unless you get very lucky - it's a flexible component anchored only around its edges and subject to various bowing forces. That's why a raft is essential - once the raft is laid, its top surface is inherently trammed to the nozzle regardless of table flatness.

Thanks Julia for clearing things up. Raft is definitely a good fix to the problem.

I just worried of the structure underneath the build plate, the structure that holds on to the ballscrew . Upon measurement from the sheet metal covering the electronics to the Z-screw structure I find a 0.2mm variants in height, I am unsure whether these would affect the prints.

I will try to print some calibration stuffs to test it out. Thanks all again.

Best Regards,


If I remember correctly, Trhuster took his Z-platform to a machine shop and milled it perfectly flat; I think it improved his prints. Not sure if it has stayed flat since.

I took a loot at this issue,

...although it's hard to do, you could try measuring how parallel the guide-rods are from the spinning rod that moves 'em. Oddly enough I found that the design of this gantry system makes it darn-near impossible to align properly without completely loosening the belt pulley's themselves. Loosening the belt tie-down (as you guys have been doing) did not yeild very accurate results. It just doesn't allow for any fine-tune adjusting.

To further complicate the adjusting, it seems the belt-tension screws impact the adjustment as well. That got me thinking that I could loosen one of the screws while tightening another for a more "fine tune" alignment. Unfortunately I just couldn't see enough of a result doing this  to get my guide-robs perfectly aligned. Also: why would they design a frame that makes it so darn hard to reach the set-screws on the pulleys? (makes me want to take a drill to the top of the frame)

ok Zortrax,

Time to tell us how to get perfect alignment...

(how do you do it at the factory?)