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.

RE: Core One owners regretting their purchase?

All the more reason though for Prusa to move away from kits. Being an amateur radio operator, of course you would be familiar with Heathkit. The idea of building your own rig (or TV etc) A. it was easy to build at home (more or less) B. was cheaper than buying (in most cases) off-the-shelf. When things got more complicated (like automated pick and place with SMD) then it because A. too difficult to build at home B. more expensive than buying off-the-shelf. And we know what happened to Heathkit after that...

I won't fault Prusa if they decide to move away from FDM printed parts and aluminum extrusions and thus away from kits. Just doesn't make sense anymore. Why do they need to maintain the expense of a 24/7 help desk to help all of the (even experienced) kit builders who screw up? What's in it for them? 

I'm pretty sure when they hand assemble these printers they are not making these mistakes and if they are, it get's caught quickly in QA. I doubt they care enough at this point to put arrows on parts, reengineer screw holes or update an assembly manual. 

I'm probably wrong but will say it anyway. The Core One is probably their last kit printer. 

RE:

I'm in the process of making my Core One, and thoroughly enjoying it. As long as you concentrate, read the steps and look at the pictures it's straight-forward and everything that could be done wrong is made very clear.

I sincerely hope that Prusa continues to offer kits as they're a lot of fun for those of us who want to put the time into making something for ourselves.

Isn't that the point of 3D printing (except for farming articulated lizards)?

RE:

I built a C1 kit for one reason: I was new customer to Prusa, and I wanted to evaluate the technology and the quality behind the pictures and marketing.

I was not disappointed, and since this is my 3rd printer full assembly, I have to say this is probably the best technology I could have bought for my money and also the best support I ever had in such an experience.

BUT I am sure this is not so much profitable to Prusa to spend hours and pay people to answer questions they should not even had if they concentrated on fully built hardware. I don't want to be rude with anybody, but reading some posts make me think this is not a beginner sport, despite the online manual quality. 

For this reason, I think Jo Prusa is right whe he writes open source has its limits, and I am not surprised C1L is not available on kit.

AC heated bed in beginners hands, even with the best posssible manual, can kill someone.  

RE: Core One owners regretting their purchase?

@audry, correct. No matter how well the manual is constructed, how clear the explanatory text and photos are there will be people who get tripped up building this kit. And there are some who shouldn't go near a screwdriver for any reason. 

An interesting case in point. I thought the section on how to properly install the X and Y motor pulleys was nicely laid out with lots of clear photos and warnings about not getting it wrong. Regardless, I can probably count on 4 hands how many posts I saw of people getting this wrong anyway and then blaming Prusa for the unclear instruction. Imagine the poor support person getting the 20th irate call (or chat... whatever) on "Why did Prusa make me install the pulley upside down?"

RE:

I the problems for Prusa with kits and the support burden they are responsible for comes from a small % of kit builders.

I mean, we had one user on here who didn’t know what a Philips screwdriver is…what are the chances on him/her successfully building a C1 from scratch ? 

I think Prusa might be guilty of overstating the simplicity of building the kit, up until the C1 you were very likely to be an experienced 3d printing enthusiast to attempt the kit, but I think with the marketing and publicity of the C1 first time printer owners just saw the kit as a way to get £$€200 off the price.

There are many pitfalls that even experienced builders could have slipped into. I include myself in that, I managed to mess up getting the right amount of teeth through the sled thing on the linear bearing…thankfully that was a pretty simple fix and once done my printer was up and running in a few minutes. 

I do not blame Prusa one bit if kits are consigned to history…I mentioned a while back that Prusa basically have to pivot or die, I suspect this could be part of the pivot.

RE: Core One owners regretting their purchase?

Rushing through the build was not something I did.  I had to wait a month after receiving it because I had hurt my back.  During that time, I read and watched videos.  Their instructions are good, but could be better.  I spent two weeks working a few hours every night assembling the kit.  A few hours was about all I could sit and work.  I read, reread, and read again. I'll see if I put it together wrong, as I suspected.

Beginners probably do a better job.  Sometimes, we experienced folks "Assume" we know the next step!  I really, really thought I checked and double-checked, but Murphy has a way of creeping into things.  There is no cost really for support, unless of course it is offset by a high fee for assembling. But, I support that staff becomes more costly if they are inefficient.  Managed  help desk for years.  I know this. I can understand the several-hundred-dollar charge for assembly.  It is time-consuming and cannot be done on an assembly line.

A I stated before, if support tracks calls, it is often necessary to say, "Well, we have tried that twice, it must be something else."  I applaud their support except for the issue of ignoring me when I said I have done that four times, doing it again is not going to help. There are only so many times you can "tune" the belts before you get PO'd at them. At some point, they are telling you that you are stupid and not following their instructions.

I am still "concerned" that two members of their team do not understand the word stroboscopic and how it works with the new belt tuner.  I have been told twice, the white LEDs play no part in a tunning method that has been in direct drive turntables for decades!

Posted by: @hyiger

All the more reason though for Prusa to move away from kits. Being an amateur radio operator, of course you would be familiar with Heathkit. The idea of building your own rig (or TV etc) A. it was easy to build at home (more or less) B. was cheaper than buying (in most cases) off-the-shelf. When things got more complicated (like automated pick and place with SMD) then it because A. too difficult to build at home B. more expensive than buying off-the-shelf. And we know what happened to Heathkit after that...

I won't fault Prusa if they decide to move away from FDM printed parts and aluminum extrusions and thus away from kits. Just doesn't make sense anymore. Why do they need to maintain the expense of a 24/7 help desk to help all of the (even experienced) kit builders who screw up? What's in it for them? 

I'm pretty sure when they hand assemble these printers they are not making these mistakes and if they are, it get's caught quickly in QA. I doubt they care enough at this point to put arrows on parts, reengineer screw holes or update an assembly manual. 

I'm probably wrong but will say it anyway. The Core One is probably their last kit printer. 

RE: Core One owners regretting their purchase?

Posted by: @mccluskey1

I am still "concerned" that two members of their team do not understand the word stroboscopic and how it works with the new belt tuner.  I have been told twice, the white LEDs play no part in a tunning method that has been in direct drive turntables for decades!

Prusa is not going to put their front line engineers on support unless they are trying to get rid of them. I'm speculating but they are probably sitting in front of a monitor with an "expert system" decision tree. Again though, just more reason for Prusa to get out of the kit business. 

RE: Core One owners regretting their purchase?

Let's be fair here. I remember the earlier discussion along the lines of "I can't use stroboscopic features because the sun is up", Which is just BS. Period.

The stroboscopic belt tuner does work, even with some stray light. Period.

Prusa support also did work on the one case I invoked it (see my "royal oak" post on trying to eliminate the failure mode once and for all for future generations). The support engineer apologized for 2 mins thinking time and pointed me to the root cause.
Of course, "one" observation is one shy of statistics 🙂

RE: Core One owners regretting their purchase?

Posted by: @mnentwig

Let's be fair here. I remember the earlier discussion along the lines of "I can't use stroboscopic features because the sun is up", Which is just BS. Period.

The stroboscopic belt tuner does work, even with some stray light. Period.

Prusa support also did work on the one case I invoked it (see my "royal oak" post on trying to eliminate the failure mode once and for all for future generations). The support engineer apologized for 2 mins thinking time and pointed me to the root cause.
Of course, "one" observation is one shy of statistics 🙂

I've interacted with support chat several times and every time they have solved my issue. They have asked relevant questions, asked for pictures, etc. I would place them a cut above the ones reading from a script.

Regards,

Mark

RE: Core One owners regretting their purchase?

Interesting points of view here, but coming back to my original post, it really feels like the value proposition of the Core One is stronger for Mk4 owners than it is for people who bought a factory built Core One. At least in my view.

I still own the Core One and have not upgraded to the plus. Part of it is laziness, but the bigger factor is that I do not even have half the filament required to print the upgrade. Buying filament just to print about fifteen dollars worth of parts turns into a sixty to one hundred dollar expense. That alone makes it unappealing for me right now.

After seeing more of the INDX system, it honestly looks like an afterthought. I like the concept of multiple heads and INDX as an idea is exciting, but the execution feels lacking. The filament boxes or dry boxes or whatever we want to call them look cumbersome, awkward, and annoying to deal with. It is still a passive solution and filaments will eventually absorb moisture again even when stored in those boxes.

Because of that, the whole INDX ecosystem feels at least twelve to eighteen months away from being genuinely usable in a day to day workflow. I cannot help but compare it to the Bambu AMS, which is more complex mechanically but offers a far more hands off experience. What I have seen so far does not translate into a better workflow for me.

For now, the Core One remains a single nozzle printer in my setup until there is a much cleaner and more mature INDX implementation. The upper section of the printer with all the tubes coming together looks unfinished and frankly messy, which does not inspire confidence.

Bottom line, my Core One is now for sale. I am fine selling it at current market pricing with a small discount. I am also disappointed that the L version received a better bed and improved electronics overall. Between that and the general workflow issues, I am not impressed with Prusa at this point.

The lack of material calibration in the slicer, the absence of a proper nozzle cleaning solution, and the overall friction in the workflow make the system feel more complicated than it needs to be. It comes across as unnecessary stubbornness and an unwillingness to adopt solutions that clearly work elsewhere, and that is frustrating.

RE: Core One owners regretting their purchase?

Posted by: @print_fandango-2

but coming back to my original post.

putting on my Prusa Fanboi! hat, the wipe tower I have to discard after an MMU print is usually "reasonably" small. Sure, purge volume needs to be configured in a single-nozzle printer, and with that in mind I know why the wipe tower is as big (or small) as it is. Squeezing more identical objects into the print bed scales down the impact proportionally. So, yes, that's the ticket I bought and so far, I'm riding the ride.

INDX, convince me once the beta testing is done. Wife doesn't need to know the details, "just a technical upgrade" 🙂

RE: Core One owners regretting their purchase?

I am sure it works, but I can't see it, even with the lights off, so I may have an issue with the LEDs.  But I have the acoustic tuner down to an art.  My white LEDs are not right I a sure, but that is not a priority.  The idea is the same used on direct drive turntables 40 years ago, so I know it works if everything is working. 

It was just the fact that more than one support tech had no clue what the term stroboscopic meant.

RE: Core One owners regretting their purchase?

Be careful because the assumption that I am wrong when I said it was not dark enough has led to the apparent additional problems that are not a priority.  Don't compound a problem by saying my response was BS.  That is a typical support answer of you are wrong and I am right.

The issues I am having now are mostly due to support refusing to listen since I couldn't get the stroboscopic to work, that they failed to understand how it works in the first place.

RE:

If the white LEDs are functioning then I don’t understand how the strobe tuner is not working. So when you turn the knob is the motor vibration frequency changing? I find it easier to view by removing the top and looking down on it. Just note that the belts are not going to be stationary, they are going to oscillate in a sinusoidal pattern when near the resonant frequency. You want to turn the knob until the peaks are at maximum amplitude.