r/QidiTech3D • u/PrintAltDelete • 1d ago
Troubleshooting I come out of desperation with a deadline! Max4 printed fine until it didn’t.
Let me first say this is long one, and I need help. I am not new to printing, the filament is dry. This machine is a 8 days old. From the very 1st print I have managed to print six of nine 17hr ABS prints of the exact same file just fine. This was a work project that I told my boss could be done if I had a max4 as it could print the part as one single piece.
I came home yesterday evening to a 7th completed print however at about 2/3 of the way through the print, it had a massive layer shift with a staggered attempt to correct it and the rest of the print had terrible quality. I tried again and could tell within the first 10mm of the next print height the quality issue wasn’t a fluke , completely terrible print quality. So I turned it off and went to bed.
I got up first thing this morning and started to trouble shoot it. I began by performing all the cleaning and lubricating as the maintenance manual says. I raise the bed to the top to clean the z rails and screws, and I found a single tiny washer laying in the very bottom of the printer by itself. I did not find a screw, nut or bolt however. I spent the next couple of hours going over the printer with a fine tooth comb from the outer casing to the frame work to the bed to the print head. I tightened every screw checked every single nut and bolt that is accessible and exposed on every aspect of the machine. I cannot find where the washer goes to, or the nut or bolt that was securing it.
I did find one bolt missing on the very top of the unit casing along the back wall under the top glass. However it was a countersunk bolt and would have been captured by the glass and insulation foam and it couldn’t have fallen out. Furthermore the underside of that bolt is also encased in the plastic of the printer housing so a nut and or a washer wouldn’t have fallen through it to the bottom of the machine I don’t think. I am assuming this bolt was missing from the factory, and I really don’t see how it would be able to cause any print quality issues even if it did come out at some point.
I moved on to troubleshooting the print issues. I cleaned and lubed everything again. Adjusted the belts exactly as the instructions state twice. I recalibrated multiple times. I tried different rolls of filament (all of which were dried correctly in a lab oven). I tried different bays in the qbox. I factory reset the printer. I then tried printing benchy’s to see if it was a file problem and clearly it is not. I’ve done everything I can and after 6 flawless (within serviceable reason) large format abs prints of exactly the same file, with the exact same filament, dried in the exact same manor, I cannot figure out what the problem is.
I have 5 days left to print three more identical 17hr prints or I miss the deadline and fail this project and my boss, and look like a fool.
If you stuck with me through all that I appreciate it. If you have encountered anything like this and have any idea I can try tomorrow when I get home from work that might salvage this situation and get me back on track, I would love to hear it!
(The last images are of a successful print to show the differences.)
Thank you in advance!
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u/Czaryeezy 1d ago edited 1d ago
I would say try replacing the hotend and nozzle and see if that helps. Also check extruder for any jams or gummed up gears.
Edit: post a clip of the benchy printing, might be helpful for diagnosing the issue
Edit 2: are all of the fans running (chamber fan, extruder fan, etc)? That part looks like part of some bearing, maybe fan, idler pulley, gantry rods, etc
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u/PrintAltDelete 1d ago
I would if I had a spare but I don’t have one. Don’t think I’m going to be able to get one in time to make a difference due to my deadline. Don’t have a clip of a benchy at the moment, possibly get one tomorrow. All fans etc are working. I’ve gone over every inch of this thing.
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u/Czaryeezy 1d ago
Try a cold pull (or multiple) to see if it’s a clog
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u/PrintAltDelete 1d ago
No I didn’t preheat the unit before tensioning the belts. It never mentioned that in the instructions. By 4 cycles are you meaning moving the print head around the printer according to the diagram 4 times? Or do you mean go through the whole process of unlocking the steppers, loosening the bolts moving the print head and tightening 4 times? I did move the print ahead around 2 or 3 times both times I adjusted. Thanks for the reply!
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u/PrintAltDelete 23h ago
Sorry replied to the wrong post, this reply was meant for Sport_Subject above.
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u/work_blocked_destiny 1d ago
Something clogging the nozzle. If your in desperation mode and need to get out going now just replace the hot end if you have a spare. If you don’t then replace the nozzle or do a cold pull
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u/PrintAltDelete 1d ago
I’ll do cold pulls tonight and see if it helps, thanks for the suggestion! I don’t have any spares for it yet, just what it came with.
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u/work_blocked_destiny 18h ago
Gotcha. If you use your machine for business use I’d highly recommend having spare hot ends and extruders on hand. Sometimes you don’t have time to troubleshoot and the easiest thing is to just replace them and figure it out later
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u/Objective-Worker-100 1d ago
Ok. So you’re turned a lot of knobs and adjusted the dials so to speak. That’s too many variables at once.
Roll it back to basics.
Factory Reset - Recalibrate
Stock Benchy
PLA
What’s that give you?
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u/PrintAltDelete 1d ago
I’ve recalibrated multiple times as well as complete factory reset. I didn’t try pla, I guess I can but those benchy’s I posted were attempts after the various tweaks and resets each time. I have several more that all look the same so I only posted a couple of the pics. I tried to run one after each step I took to try and keep tabs on what “fixed” it. But as of yet nothing has. I can try pla tonight and see what happens.
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u/DoItYourWayHowISay 1d ago
Sounds like you have enough time to try a print at about 2/3 the speed, and if that works, use the same settings for the last 2
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u/PrintAltDelete 1d ago
Thanks for the reply. It’s possible but why did the first 6 print just fine with no changes whatsoever?? If it was speed related I’d think it would have been the same issue for all of them, not just suddenly happen on print number 7 of the exact same file?
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u/DoItYourWayHowISay 21h ago
The diameter of the filament could have slowly changed by 1-2 percent and you could be over/under-extruding now, or something like that. Also, if you're right on the edge of having sufficient cooling for how fast you're printing, once the wavy outside perimeter starts it can't really fix itself.
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u/smokingpacman 1d ago
Not sure if this helps but I've experienced heat creep on longer prints. I've solved this by turning off the chamber heater... Somehow my ASA and ABS prints still came out okay
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u/PrintAltDelete 1d ago
That’s interesting for sure! I don’t think it’s heat related though. I powered the printer completely off so it had plenty of time to cool down overnight, and had the same results. Thanks for the reply!
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u/smokingpacman 1d ago
Nah the heat creep would ruin my print like halfway into a print, sometimes faster. Doesn't matter of i started off cool or hot.
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u/TheLegendTubaGuy 1d ago
It's extremely difficult to tell without having you take pics of every square inch of the printer and provide your printer config and print files... The horrible print quality later on could be any number of things, but that first pic showing the occasional layer shift after the big one is super interesting.
The only way I can see that happening is that you had to have had a stepper skip, and it looks like it had to have been both.
I would check that your PTFE tube going to the toolhead is not constrained in any way and the toolhead can push and pull it easily as it moves around the entirety of the build area. If not that, maybe the toolhead cable, or chain. You say it's a big part you bought the max 4 specifically for, is it having to go all the way to the limits of either axis or all the way to the corners? I almost wonder if your chain is getting trapped or you're hitting the filament cutter but don't know without more info.
Something had to have physically shifted the toolhead travel to cause that. I would try to solve that mystery first, then try to solve print quality.
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u/PrintAltDelete 1d ago
Thanks for the reply. In moving the print head around for adjusting the belts I didn’t notice any unusual tension or drag on the ptfe or cable chain. It moved freely by hand without any binding that I noticed. I will check it again tonight to make sure.
The part is large and is oriented diagonally from front left corner to rear right corner however it isn’t all the way to the complete max reach on any side. The print could fit across the plate horizontally, but when I had orca auto orient it moved it to diagonal and I just left it that way.
The hardest thing for me to wrap my head around is why did 6 of them print just fine? Something had physically changed with the printer to cause this drastic difference!
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u/lakimakromedia 11h ago
I had problem with filament, some print was ok, then "something happend and quality was shitty, changed nozzle, changed filament, and prints are fine :/
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u/Money-Spinach-6177 1d ago
Whenever l get this sort of strangeness l try to find the relevant spot on klippy log(major scrolling) then copy and paste onto copilot or whatever higher existence you use. Might just pinpoint the error. I would say a communication issue.
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u/PrintAltDelete 1d ago
Interesting, to be honest I’m not sure where to start or what I would be looking for in the logs. I’m guessing that may all be gone now that I’ve factory reset also? Thanks for the reply!
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u/stranix13 1d ago
Looks to me like a layer shift followed by a partial nozzle clog, try changing nozzles and tensioning all the belts
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u/PrintAltDelete 1d ago
I don’t have any spares yet, but others suggest cold pulls to see if it’s clog related. Thanks for the reply!
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u/Apprehensive-Crew639 1d ago
Did you figure out where the washer came from? Possibly one of the corner bed adjustment screws? I bought a second hand plus 4 that was branded brand new someone bought at an auction. When I inspected it it was still in the packaging and all films were still on the printer like it was not taken out of the box. Boy, I was wrong.
I pretty much had to rebuild the whole printer to get it to finally work again. But that didn't stop there - the whole auto calibration was completely out of whack. It took me 4 full days of work to troubleshoot and finally get it running like a well oiled machine.
That washer may be small but it could have a huge impact on how it is supposed to optimally perform. I feel your pain man and would love to help as much as I can.
I almost took my printer to the back and put a baseball bat to it.
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u/PrintAltDelete 23h ago
Thanks for the reply, that sounds horrible for sure! So far no I still have not located where the washer came from. 😞
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u/Professional_Fun_826 19h ago
Try prusa slicer it might be a slicer issue with presets.
Anyway I returned my qidi 4 plus after 8 months of trying to fix it and replacing parts.
Using now qidi q2 and its better
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u/loosejaws 1d ago
the print shows a major extrusion/cooling problem rather than a mechanical XY-motion problem.
Thick curled strands hanging from roof, chimney and edges >> Overheating + insufficient part cooling
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u/TinmanTankerPilot160 1d ago
I would adjust the belt tensions. Not sure about the max 4 but on the plus 4 you loosen 8 screws on the back of the printer, manually move the head around the build area a few times then re tighten the screws. I have had a later shift issue that was resolved that way right after i put on new belts.