Printing head calibration going wild
Hello,
I'm not sure if this is normal behaviour since this is my first printer ever, but as you can see on the video below, the printing head keeps banging in the front right corner every time I start a print. Both belts are tuned to 85Hz.
Yesterday I printed Benchy, and the printing head was also banging the corner, but for much less time. Eventually it started to print, but this time it's been doing this for over 3 minutes...
Please advise,
Thank you!
RE: Printing head calibration going wild
SOLVED!
I had to bent gantry a little bit and re-tune the belts.
RE: Printing head calibration going wild
This is such an annoying issue. Prusa need to add an option for it to stop and either produce an error, or just carry on regardless. At the moment the only option is to wait, or reset the whole printer!
RE: Printing head calibration going wild
So what is the answer for this, I have the same problem.
RE: Printing head calibration going wild
how exactly did you bend the frame? Do you have any pictures and a more detailed recommendation. I am having the same issue - it's impossible to calibrate the X and Y axis. The printer head is always banging in the top right front corner.
RE: Printing head calibration going wild
Support will send you a video on how to adjust the gantry. I have done it by following their directions and it is quite easy once you figure it out.
It is very important to loosen up both sides of the belts, completely. Although you can bend the gantry OFF square by bending/pulling one side without loosening the belts, you will be putting stress on the belt adjuster/pullies and you will pull them off or break them in half. Ask me how I know.
So best is to loosen the belts completely, THEN, bend the gantry to get it square, confirm that both sides are square to the front, THEN, re-tighten both belts. I have since tuned my belts several times and this method makes both tuning the belt and squaring the gantry up very easy, without damaging the belt tensioners (it is a 3d printed part).
My machine came with both incorrect belt tension and off square gantry from the factory. After tuning the belts correctly, I had to re do it again as the belts came loose (both sides showed to be 80hz instead of the 85 I had them at). No idea why that happened, maybe one of the adjusters had not slid properly and it came lose while printing, loosening the belt ( you will see in some cases the screw wants to pull out rather than sliding the adjuster in/out). This might not make sense now but it will once you do this process once.
All that to say, once I got both the proper tensions things improved generally speaking. Most notoriously was that the homing sequence at the beginning of every print is now consistent rather than banging indefinitely.
RE: Printing head calibration going wild
All clear, thank you so much for your help.
I'm embarrassed to say, but the root cause of my problem was the incorrectly mounted pulley. Once I took this all apart and correctly mounted it, everything worked like a charm 🙂 😋
RE: Printing head calibration going wild
Regarding my issue with head calibration. I had a chat with Support and they advised to ensure the chassis was contacting evenly in the front and to then recalibrate the belt tension. This worked for me. I have attached a video that support acknowledged as normal behavior, knowing what's normal is a big help for me.IMG_2812
RE: Printing head calibration going wild
Do you have the video support sends with the instructions?
Support will send you a video on how to adjust the gantry. I have done it by following their directions and it is quite easy once you figure it out.
It is very important to loosen up both sides of the belts, completely. Although you can bend the gantry OFF square by bending/pulling one side without loosening the belts, you will be putting stress on the belt adjuster/pullies and you will pull them off or break them in half. Ask me how I know.
So best is to loosen the belts completely, THEN, bend the gantry to get it square, confirm that both sides are square to the front, THEN, re-tighten both belts. I have since tuned my belts several times and this method makes both tuning the belt and squaring the gantry up very easy, without damaging the belt tensioners (it is a 3d printed part).
My machine came with both incorrect belt tension and off square gantry from the factory. After tuning the belts correctly, I had to re do it again as the belts came loose (both sides showed to be 80hz instead of the 85 I had them at). No idea why that happened, maybe one of the adjusters had not slid properly and it came lose while printing, loosening the belt ( you will see in some cases the screw wants to pull out rather than sliding the adjuster in/out). This might not make sense now but it will once you do this process once.
All that to say, once I got both the proper tensions things improved generally speaking. Most notoriously was that the homing sequence at the beginning of every print is now consistent rather than banging indefinitely.
RE:
This is how I fixed my gantry: https://www.youtube.com/watch?app=desktop&v=myLZtFy0nhw
Just don't bend too much at once, bend a little bit and then check. Repeat until you have no play on each side.
RE: Printing head calibration going wild
That's great, I did not know these videos existed!
Thanks
RE: Printing head calibration going wild
Important:
Do it like in the video, but keep an eye on the belt tension! One belt, depending on the side you're pulling, will tension up A LOT.
You want to bend the brackets of the linear rail, NOT stretch the belt (or rip it off, snap it etc.).
So pull slightly, check if and which belt is tensioning up and make it more slack, before pulling further.
RE: Printing head calibration going wild
£1130 / £874 for an assembled / kit printer and you have to arbitrarily bend bits and guesstimate by eye whether you've got it right, then re-assemble / re-tension belts only to find you were a bit out and then repeat until it works. This doesn't fit the 'Prusa quality' image.
Surely Prusa can come up with a more accurate process to produce their parts - or at least come up with a more accurate user process to correct their manufacturing shortcomings (check diagonals of XY assy are equal or provide a frame to guarantee 90 degrees in corners?).
RE: Printing head calibration going wild
Best practice as per support is to loosen all belts completely. No issues of ripping or stretching anything then.
RE: Printing head calibration going wild
Surely Prusa can come up with a more accurate process to produce their parts - or at least come up with a more accurate user process to correct their manufacturing shortcomings (check diagonals of XY assy are equal or provide a frame to guarantee 90 degrees in corners?).
I guess, that the brackets are designed to bend, before the Y-Axis bearing can get stuck and damage the printer.
That wouldn't really be an issue, if the calibration wouldn't be, what it is..
I have no idea who came up with the idea to bang the print head multiple times against the end-stops, without some sound dampening.
I also absolutely don't know why Prusa thought it would be a good idea to annoy 99,99% of customers for 99,99% of prints , just to get an almost invisible seam, if a power outage happens.
If no power outage happens during a single object, half a millimeter off-set wouldn't be an issue and there wouldn't be the need for more than one bang per axis. *tock* *tock*, printing.
This extra accurate banging should be an optional setting for power outage protection..
RE: Printing head calibration going wild
Agreed. This printer is trash
RE:
I have no idea who came up with the idea to bang the print head multiple times against the end-stops, without some sound dampening.
Perhaps it's a 'built in auto correction' feature ... trying to automatically bend the brackets back to 90 degrees using the printhead - instead of getting us to do it 😆
RE: Printing head calibration going wild
Ok, I take this back. Assembler (me) was trash at putting the pullies together on the CoreXY. Went through and made sure that all the pullies had plenty of room to move around--took them all out and put them all back in. Quite the pain while trying to keep the belt installed. But it worked!
Also, I decided to tension the belts using a proper tension gauge. The magic tension for 86hz on my printer was 3.15 lbs. +/- .05 between the two belts to compensate for the gap between the extruder rail and the front of printer (the part that goes bang bang bang when things aren't set up correctly).
Once I had that set it Y-axis issues went away immediately, and auto-home took less than 30 seconds with minimal banging (longest part was waiting for the bed to raise for the z-axis calibration).
Definitely pay close attention to how tight you screw in the pullies--they should be able to wiggle around a bit.
RE: Printing head calibration going wild
Hello!I ordered my Core One conversion kit on the first day, it was delivered relatively quickly, sometime in early May.I built the new printer, it passed all the tests at first, at first there was a small hammering in the right front corner, I adjusted the belt settings a little, the hammering stopped.Printing started fine for two weeks, then it thought for a moment and started hammering the right front corner again for 2-3 minutes. Re-tensioning the belts, running tests, recalibrating, the hammering stopped.Everything was fine again for two weeks, now it started again, I tried everything, 5-6 hours of trying with support, no results, it refuses to start properly, it writes different error messages every time it starts. I'm fed up with it, I've never had such a crappy printer before. I want to send it back to Prusa, they haven't been able to tell me how it's going for three days, they don't know how much money they're willing to refund, and the best part is that they're not willing to take back either the camera or the accelerometer, along with the four printer plates. So I have a room decoration, a useless printer. It's all a joke, I'm thinking of suing them in a European Union court.I've read similar posts on several forums, some are already working on forming a lawsuit.
RE:
Although understanding your frustration, it might be easier to get it to work, than keep being as frustrated, as you are.
- when you switch on the printer. Is it already giving errors or only when you start a print?
- when you just switch it on and wait until it's ready (no preheat!). Does it also fail the "Auto Home" from the LCD menu? (Control - > Auto Home)
- if you get it to switch on and boot up fine, the Auto Home without preheating works fine too and your belts are between 80-110 Hz, your printer is ready to print.
- if you start a print and then it's going crazy with calibration errors, nozzle cleaning errors and probing errors: look up for the custom G-Codes that disable the hotend heating for these steps in the Custom Start G-Code. For me that solves all these issues.
M104 S0 ; disable hotend heater
Put that before the G28 command, the short G29 command without a comment (it's the nozzle cleaning) and before the G29 command-block for MBL.