First Layer Quality Degrades Over Time  

Re: First Layer Quality Degrades Over Time

Hi!
Did you come to a solution to your problem?
I bought my MK2S used an have experienced similar problems...

Re: First Layer Quality Degrades Over Time

The biggest single issue with mk2 is pinda's thermal sensitivity
Simply raise the extruder to say 60mmm every time you prepare to start a print and this problem pretty much dissapears
Regards Joan.

Re: First Layer Quality Degrades Over Time

Hi!
Did you come to a solution to your problem?
I bought my MK2S used an have experienced similar problems...

Not yet. I get good runs and bad runs without changing a thing. Still trying to figure it out.

Re: First Layer Quality Degrades Over Time

The biggest single issue with mk2 is ponds thermalsensitivity
Simply raise the extruder to say 60mmm every time you prepare to start a print and this problem pretty much dissapears
Regards Joan.

Thanks, Joan. I will give this a try. (I'm assuming you mean the mk3!)

Re: First Layer Quality Degrades Over Time

you can possibly see I was either inebriated, of typing on my mobile phone when I responded earlier...

I hate predictive text/// and I can't spell... together - not a good combination...

inductive sensors seem to be thermally sensitive, in general...
the Mk3 has a thermistor integrated, and a temperature compensation routine added. to address this...

er.n mentioned having a mk2s...

I had a mk1, with manual levelling... very fiddly... I updated to Mk2 and auto bed levelling was introduced,
it was better than manual, but you could find yourself chasing the perfect first layer... that was when I found that always raising your extruder to about 60mm, before starting a print... reduced the issue significantly...

even though the Mk3 has thermal compensation, I still go old-school, and raise the extruder...
may not be necessary, but as I switch between Mk2 and Mk3 for jobs, I find it easier to do both, the same way... rather than forget on the mk2 and perhaps have a duff print!

regards Joan

Re: First Layer Quality Degrades Over Time

Thanks for the attempt, Joan. Unfortunately raising the Z-axis prior to each print did not solve the issue. I appreciate the advice, though!

Re: First Layer Quality Degrades Over Time

Full disclosure: This is my first 3D printer and I've been learning as I go.

I'm experiencing an issue where my first layer prints great for a while and then starts getting worse print after print: sometimes adhesion issues, sometimes, gaps, sometimes both in the same print. Minor at first, but getting progressively worse print after print. Any help would be GREATLY appreciated.

One thing that you're learning about 3D printing is that there's a million things which can go wrong and it's not always obvious what the problem might be. It's pretty common to chase red herrings.

* I started having adhesion issues, and addressed them with Acetone, switching filaments, etc. But no re-calibration or physical fixes, playing with live-z, etc. I'm not sure what fixed the issue but it went away for a while.

This is useful to know. The printer did work at one point, so something must have changed.

* I flashed to the latest firmware.
Here's something that changed. It might be a red herring, though. Did you try downgrading to the old firmware?
* About this time I noticed that when the printer went through it's pre-print routine it was making a relatively loud clunky noises (as compared to before) when zeroing the x and y axis.
This is probably normal. The printer finds the zeros by banging against the end stops. But, if you had something come loose, it's possible that the initial zeroing routine is making it worse.
* First layer quality degraded severely over the course of a week or so and the printer became on usable.

* I noticed the bed had developed a wobble which led me to the fact that the u-bolt on one of the y-carriage bearings had come loose.

* I disassembled the y-carriage re-tightened all bearings, reassembled, and re-ran the wizard.
This definitely would have caused problems. But it might not have been the only problem, or you might have accidentally caused new problems when you fixed this one.

* I had to cancel out of the calibration 3 or 4 times as the print head kept catching on the paper, first at position 2, and then 3.

* I tried to readjust the PINDA probe, but I'm not sure i actually accomplished anything.
This might be a problem. Maybe you should repeat this step in case you didn't get it right. If you're been disassembling and reassembling the printer, it's easy to put something back together just a little wrong.

* Printer finished wizard, I re-calibrated the z-offset using Jeff's Method and I printed great for about 3-days.

* Quality is again degrading with some gaps, some bumps and some adhesion issues all in the same print.

* I checked the bed for level with a straight edge and it seems fine.

* Sometime since the last re-calibration I noticed that the line that prints on every print between z-calibration and actual printing is consistently inconsistent. The first inch or so is thinner than the rest, and the remainder is thicker (by maybe have again as much) and has ripples on top. The size change happens at the same spot every time.
This is normal and expected. If you look at the gcode for that purge line you will see that it commands extra extrusion for the second half of the line.

* It's worth noting that somewhere during all of this I started using the "life-z" z-offset method posted by Jeff on here.

I'm getting ready to re-calibrate again, and see if that buys me a few days. That's obviously not the way it should be though. I would appreciate any and all advice.

It sounds to me like you found one significant assembly problem (loose U-bolt on the Y carriage), and it's possible your PINDA isn't quite right. It's probably worth going around the entire printer and checking every bolt and screw to make sure nothing else has worked its way loose.

One thing that's not clear, though: when you say the first layer quality degrades over time, are you doing a whole bunch of prints in a row so the printer is more or less running nonstop? Or does the printer sit idle for a few hours between prints?

One other possibility if you're running 24x7 is that you've got a heat-related issue, where something is going downhill as the printer gets good and warmed up.

Re: First Layer Quality Degrades Over Time

Peter,

Thank you for the detailed and insightful comments!

Rest assured I'll be following it this weekend!

Scott

Re: First Layer Quality Degrades Over Time

Short version: I went through and re-tightened all screws - some were slightly loose, some were not.

I also re-calibrated the temperatures. In infrared thermometer was showing about 10 degrees C cooler than the LCD. After re-calibrating, the difference went down to < 2 degrees.

After that I reran the start-up wizard and redialed in z-offset. The z-offset changed from 1.000 to 1.112.

Prints seem to be fine for now. We'll see if it holds up.

Thanks again, Peter.

Detailed responses:

Full disclosure: This is my first 3D printer and I've been learning as I go.

I'm experiencing an issue where my first layer prints great for a while and then starts getting worse print after print: sometimes adhesion issues, sometimes, gaps, sometimes both in the same print. Minor at first, but getting progressively worse print after print. Any help would be GREATLY appreciated.

One thing that you're learning about 3D printing is that there's a million things which can go wrong and it's not always obvious what the problem might be. It's pretty common to chase red herrings.

Yes, I've definitely learned that!


* I started having adhesion issues, and addressed them with Acetone, switching filaments, etc. But no re-calibration or physical fixes, playing with live-z, etc. I'm not sure what fixed the issue but it went away for a while.

This is useful to know. The printer did work at one point, so something must have changed.

* I flashed to the latest firmware.
Here's something that changed. It might be a red herring, though. Did you try downgrading to the old firmware?

I'm currently still on the upgraded firmware.

* About this time I noticed that when the printer went through it's pre-print routine it was making a relatively loud clunky noises (as compared to before) when zeroing the x and y axis.
This is probably normal. The printer finds the zeros by banging against the end stops. But, if you had something come loose, it's possible that the initial zeroing routine is making it worse.

Understood. I think they got louder as the y-axis bearing came progressively looser. It's back to normal since fixing the bearing.

* First layer quality degraded severely over the course of a week or so and the printer became on usable.

* I noticed the bed had developed a wobble which led me to the fact that the u-bolt on one of the y-carriage bearings had come loose.

* I disassembled the y-carriage re-tightened all bearings, reassembled, and re-ran the wizard.
This definitely would have caused problems. But it might not have been the only problem, or you might have accidentally caused new problems when you fixed this one.

* I had to cancel out of the calibration 3 or 4 times as the print head kept catching on the paper, first at position 2, and then 3.

* I tried to readjust the PINDA probe, but I'm not sure i actually accomplished anything.
This might be a problem. Maybe you should repeat this step in case you didn't get it right. If you're been disassembling and reassembling the printer, it's easy to put something back together just a little wrong.

Good advice. I generally find it difficult to adjust the height of the PINDA probe (on the initial install and here). It seems pretty 'locked in', even with the screw loosened. If there's a trick to it, I'm missing it.

* Printer finished wizard, I re-calibrated the z-offset using Jeff's Method and I printed great for about 3-days.

* Quality is again degrading with some gaps, some bumps and some adhesion issues all in the same print.

* I checked the bed for level with a straight edge and it seems fine.

* Sometime since the last re-calibration I noticed that the line that prints on every print between z-calibration and actual printing is consistently inconsistent. The first inch or so is thinner than the rest, and the remainder is thicker (by maybe have again as much) and has ripples on top. The size change happens at the same spot every time.
This is normal and expected. If you look at the gcode for that purge line you will see that it commands extra extrusion for the second half of the line.

Thanks! I'm most definitely a gcode novice!

* It's worth noting that somewhere during all of this I started using the "life-z" z-offset method posted by Jeff on here.

I'm getting ready to re-calibrate again, and see if that buys me a few days. That's obviously not the way it should be though. I would appreciate any and all advice.

It sounds to me like you found one significant assembly problem (loose U-bolt on the Y carriage), and it's possible your PINDA isn't quite right. It's probably worth going around the entire printer and checking every bolt and screw to make sure nothing else has worked its way loose.

Done!

One thing that's not clear, though: when you say the first layer quality degrades over time, are you doing a whole bunch of prints in a row so the printer is more or less running nonstop? Or does the printer sit idle for a few hours between prints?

It probably averages about 20 hours / day of run time, with a 4 hour break before the cycle starts again.

That being said I mean the quality degrades from print run to print run rather than from print to print. The batches get progressively worse.


One other possibility if you're running 24x7 is that you've got a heat-related issue, where something is going downhill as the printer gets good and warmed up.

Certainly worth considering.