Core One owners regretting their purchase?  

RE:

Posted by: @mccluskey1

Before I completely disassemble the XY carriage and start over, I need a check.  See photo.  On the top right side, with the gantry all the way back, the belts actual appear to touch.  This concerns me.  Is that correct?  I am taking things in steps to see if I have a rub or blockage.

That is indeed not correct. It looks like you have mounted the right "linear holder" (the block which holds the two idler wheels, and attaches the X rail to the Y bearing) the wrong way round. Its straight side needs to be oriented towards the front, and the side with the step towards the back. See the two photos below which show the same part in my printer.

We just had someone with the same build issue in the German forum section. It also caused the Y axis test to fail, and once he mounted the linear holder correctly, this was resolved.

RE: Core One owners regretting their purchase?

As the TO apparently chose to not get involved in the discussion he or she started, I believe this thread should be ended, particularly as the above explanation by @jurgen-7  is way too valuable to be buried in this thread, but should be placed in the Core One troubleshooting section. @joantabb, what do you think?

Jürgen, do you plan to leave a note in the builder's manual to explain where people can go wrong? I am about to do so due to an out-of-spec trapezoid nut which caused a Z calibration failure and ended  up in pulling one of the front right motors from a freshly build Core One+ and salvaging a likewise nut from my MMU3 🙂 

Best
Chris

Regards

Chris

RE: Core One owners regretting their purchase?

Posted by: @justme3d

Jürgen, do you plan to leave a note in the builder's manual to explain where people can go wrong?

Sure, I can add a comment there. Although I am rather disappointed with Prusa's handling (or lack thereof) of comments in the build guide. I was among the very early kit builders and left several notes, including some on non-trivial traps. I don't think any of them were incorporated into a revised build guide. And with the recent publication of the Core One+ build guide, no user comments were copied over from the Core One edition, so they are all effectively lost for new builders.

RE: Core One owners regretting their purchase?

I have my fingers crossed that this is the problem.  With the instructions often flipping the XY assembly from top to bottom and right to left, I have been looking for some sort of binding.  I had spent several hours moving the X, Y, and Z axis and watching before posting last night, looking for a bind or rub.  I just felt like that was the issue.  Even sitting for hours last night comparing the photos and instructions, I just didn't see it.  That is why my next step was to disassemble the XY assembly and rebuild it.

I spent 40 years of my life doing computer hardware installations, support, and troubleshooting.  As part of that, I wrote and rewrote instruction manuals and redid photos back when computers had boards, switches, and jumpers that had to be installed.  I learned then, through experience, that if something can be assembled incorrectly, it will be, unless a way to prevent it is found.

Taking care of problems like that for 10 years for a company I did support for which manufactured component boards to be installed in computers, I taught them to use "keys" and explicit instructions and photos to prevent people from doing what they could.  Over 40 years of troubleshooting, I learned that when the obvious, suspected solutions continue to fail to fix a problem, it is time to step back, punt, and reassess.  Over the years, when the obvious solutions failed, I have totally disassembled a computer or piece of equipment and started over with others' help.  No fault of Prusa support other than not listening to the "I have done that over and over with no luck."  Support is a hard job, especially when you can't put your hands on it over the phone!  Just being there 24/7 is incredible in today's world.

This is a complicated piece of equipment with plenty of places to go wrong, and it still operates.  I applaud the work in the instruction manuals.  I will double-check and reorient if that is the issue in a day or so.  Holiday family time comes first.  Let's keep our collective fingers crossed and hope we learn something other than "check the belt tensions," ad nauseam.

I can print things fine that do not extend beyond about 85% of the plate's use.  My troubleshooting told me that something limited the outer use of the equipment.  And that at the extreme points of movement, I had a problem.  Fingers crossed!

May we receive a lesson learned.  Thanks to all for the ongoing help and support, and for dealing with my frustration levels.  Sometimes, a collective group of experts still misses things.  When I would write instruction manuals years ago for the installation of complicated hardware and software, to beta test, I would go  get one of the non-technical secretaries and have them try to assemble and install.  Fresh, naive eyes can often find the problem!  What I could have given for a cell phone photo in those days!

I am not sure what the above poster means in their post, but I agree that if this resolves the issues, something should be noted.  I dealt with a filament grinding problem for a few days before I disassembled the entire Nextruder to start over...again.  During one of my prior disassemblies, the tiny thin washer had disappeared behind the gears on the motor shaft. That was all it took.  Amazon to the rescue! Problem solved!

RE: Core One owners regretting their purchase?

Fingers crossed here as well!

Posted by: @mccluskey1

I spent 40 years of my life doing computer hardware installations, support, and troubleshooting.  As part of that, I wrote and rewrote instruction manuals and redid photos back when computers had boards, switches, and jumpers that had to be installed.  I learned then, through experience, that if something can be assembled incorrectly, it will be, unless a way to prevent it is found.

I agree, Prusa missed a "Poka Yoke" opportunity here: Either design a part to be fully symmetrical, so orientation does not matter -- or design it in a way where it is impossible to install it the wrong way round.

Actually I was a bit baffled that it is possible to mount the idler blocks when rotated 180°. It takes some doing in positioning the screw holes to make that possible! In fact, there is an extra tapped hole in each of the metal L brackets (left & right). If Prusa had not provided those unnecessary holes, it would not be possible to install all three mounting screws for the linear holder when it's oriented incorrectly. Little glitch... 🙄   

RE:

If you have indeed found my assembly error, I agree that we learn from mistakes.  Since Prusa prints all these parts, adding arrows, letters, and keys to indicate orientation should not be hard.  Let's see what we learn!

This could very well be why I had such difficulty with the belt installation.  As you had stated, the issues I had with belts were not common.  But maybe it pointed to another problem.

Checklists work great.  During my tenure as a phone support tech, we developed a large database in which every problem/solution was tracked and documented.  Based on that, we had a knowledge base we could search for keywords, and this was 30 to 40 years ago!  In support, you had to learn from others' mistakes as well as your solutions, or you ended up solving the same problems over and over again.  Out database solution made onboarding new support people much easier.