XYZ calibration fails - Calibrating home puts print head in middle of X axis??  

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Hi Mike,

did you lube the Linear Bearings?

does the X axis move smoothly both ways by hand?

regards Joan

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Thanks for the quick reply!  I did not lube the bearings.  The X axis does seem to move smoothly both ways by hand (with what I assume is a proper amount of resistance given that I'm operating motors with the power turned off).

What is the best (locally available) alternative to the Prusa lubricant?  I'm working on printing PPE for local health workers, so I'd rather not wait for it to ship if possible, but I also know that not all lubricants are the same, and I don't want to make things worse.  I saw this article, but didn't know if you had a specific recommendation?

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

do you have any bicycle grease, or 3 in 1 oil, or machine oil or Light  general purpose grease? 

virtually anything is better than nothing!

keep away from HEAVY grease, Water based lubricant and WD40 water displacement spray... 

Be wary of Silicone grease! silicone can contaminate your build plate. 

regards Joan

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

I don't see why fresh engine oil can't be used, but it does tend to be smelly!

used engine oil is NASTY....

lol

joan

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Thank you for your help.  I did find some lube that must have come with the printer when I ordered it, so I used that.  I also checked all my cabling and arranged them a little better to ensure none of them were interfering with the print head, motors, or belts.  The first several times I tried it again after doing that, it still failed, though it behaved a little differently (the head didn't stop at the same X axis position as it had previously.  I turned the printer off and took a break for awhile.  When I came back, I decided I would take another video of how it was behaving so I could illustrate the current situation, and lo and behold, it successfully completed the XYZ calibration!  So I'm glad that it seems to be working now, but I'm nervous that I can't put my finger on what fixed it (and therefore know for sure that it is really fixed).  I'm going to try a test print and see if it truly works as it should.  Thanks again for your prompt help!

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Hi Mike, 
I suggest that you wipe the smooth rails clean and lube again, then with luck the printer will run a while before you next need to lube. 
next time you do an upgrade you can lube the bearings properly.

regards Joan

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Now the XYZ configuration is consistently successful, but only if I manually home the print head all the way to the left side of the X axis.  If I do not manually home it, it searches too far to the right of the first calibration point.  At least it is consistent at this point.  However, when I attempt to print anything, the print job begins, but at some point part way through, it just suddenly fails with a crash detection message, then attempts to reset, but the print resumes too far to the right on the X axis, and either crashes again if the head attempts to travel to the right of the bed, or continues printing in the wrong place.  One time it failed in this way even before the actual print started... while the print head was making it's initial trip around the perimeter of the job.

For some examples, see https://photos.app.goo.gl/tMFYPHXHoeD7NAnW9.   There are two videos: The shorter one is when the print failed before it even started.  In the longer one, the crash occurs at about 5:30, and was the second time a crash occurred at the exact same place in the print (there are two photos that look very similar, from two different prints).

I have tried re-flashing the latest firmware, and even tried rolling back to a previous firmware version, but the behavior continues.  What else can I try?

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

I'm not sure why the link in my previous post isn't working.  Try this one to see the images and videos of the failed print jobs:

https://photos.google.com/share/AF1QipMtBRybCfo5bp3OJEQ9_V0ireGb1wEd5CgGKE2R0Sk2lAa3yhOR_-iZh-7SI4NhuQ?key=YllFWVlNMDBySjFxaVp2aGFWTHJOczc4clRPckhn

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

@mike-stoltzfus

Did you try lubing the smooth rods?

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Yes, I lubed all the smooth rods, for all three axes.  I reflashed the firmware to the latest, I recalibrated.  It still did the same thing (crashed very near the beginning of a print job and then resumed printing at the wrong spot in the X axis.  This is really frustrating.  Here are a couple of other things I noticed that are odd:

• Immediately after the crash, I attempt to stop the print in the menu.  When I navigate to stop print and press the knob, it says something about auto-unloading the filament (as if I had selected the Unload Filament menu option.  The first time or two it did that, I thought I might have just accidentally navigated to the wrong menu item, but this time I was very deliberate, and yes - it responded incorrectly when I pressed the knob to Stop Print.
• There is definitely an issue with the Calibrating Home part of the self check.  When it comes to that part, the print head grinds along the X axis, moving only a little back and forth, but working its way away from the left side of the axis, until it is well past the first calibration point in the bed.  This causes the XYZ calibration to fail, unless I manually push the head back to the left side of the X axis.

What else should I be checking?  Could it be some kind of problem with the Gcode (which doesn't seem likely because I have tried multiple models, including the Benchy), or something wrong with the firmware (which also doesn't seem likely because the printer was working fine before it was disassembled for cleaning and reassembled, and also it seems these issues would be more wide-spread if it was a firmware issue)?  Or could it be a hardware issue like a belt too tight or loose or one of the motors malfunctioning or misadjusted?  I just don't know enough to know how to troubleshoot.

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

@mike-stoltzfus

was working fine before it was disassembled for cleaning and reassembled:

How much(what) did you dissambled? What parts?

Check if you did damage the pinda cable, look if it works on the places it should, and maybe the light goes on/off on the wrong places, you could also solder a new cable if you are handy, one of my fans cable I pulled a new cable on the outside of the cable sleeve/wrap so I did not have to disassemble all again.

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

The entire extrusion head assembly was removed, as well as the Z axis motors and rods, and some cables were unplugged from the control unit.

You mentioned the light going off/on at the wrong places... I notice that if I don't manually move the extrusion head all the way left before doing the XYZ calibration, after it does its initial search for the first calibration spot (the circular motion), it does the back and forth movement, and the light rapidly flashes the entire time it is doing the movement.  (As opposed to only flashing on when it moves over the calibration spot when it's calibrating properly.)

Our next consideration is to disassemble the printer again, then re-assemble it, being extra careful and double-checking each step as we do it.  (The last time we assembled it, my 17 year old son did the reassembly.  Though he knows what he's doing, I would feel better following the steps with him to make sure he didn't take any shortcuts, or hurry through any of the steps.)  I was hoping not to have to go through that process, but if that's my best next step at this point, that's what we'll do... unless any of you have any other suggestions of things to try?

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

You could try to play with the position of the pinda.

Try in a few steps higher, move always a little. And then also a little lower. First adjust like in the manual.

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Check the PINDA. Raise Z to about half-way. Go to the sensor status on the LCD and move the extruder left and right; trigger the PINDA at different positions(hold a piece of metal to it with tape), wen moving see if pinda fails.

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

@peter-m26

Thanks for the replies.  I have fiddled with the height of the PINDA as you suggested, and it hasn't seemed to make any difference.  We checked the sensor status, and it is working as expected (1 when detecting metal/light off, 0 when not detecting metal/light on).  The whole issue seems to be the X axis.  Here is what we are observing (as I've mentioned before):

• During the self test, when it does the Configuring Home stage (just after the Z axis test), the extruder assembly stutters along the X axis until it's near the middle of the bed, then the bed stutters back and forth a few times along the Y axis, then everything comes to rest, but in the wrong spot on the X axis!
• If the extruder assembly isn't manually re-positioned to the far left side of the X axis, the XYZ calibration fails because the PINDA isn't searching in the right spot.
• During the bed leveling calibration, the extruder checks nine locations on the bed.  My son (who used this printer at school before it was taken apart) says the nine locations it is checking are wrong - they are shifted too far to the left.  (The first is on the far left line, right along the edge of the metal plate, and he says he thinks it should be in the middle, between the lines rather than right on it.)
• When a print job fails with crash detection (which is happening every time, but at different times during the job and sometimes before the job even starts), it repositions at then resumes at the wrong spot on the X axis, often too far to the right (in which case it almost always crashes again immediately since it runs off the right side of the bed).

In short, it seems like something is causing the X axis control to behave incorrectly.

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Power cable x-axis maybe broken.

Turn printer on, and move via menu, the x-axis around, and touch cables and see if it fails, check also the connectors in de electronic housing.

Also change the height of the z-axis, and check the x-axis again moving over the bed.

RE: XYZ calibration fails - Calibrating home puts print head in middle of X axis??

Re bumping because this is my exact same issue and I cannot find a solution