Multiple print failures  

RE: Multiple print failures

@zoltan - you can't test for filament jams if other problems are causing fails.  These things need to be sorted out one thing at a time.

RE: Multiple print failures

Posted by: @epzcaw

I did jeffjordan's calibration modle.  See image.  I've marked what I think is the best one.

One issue is that this was printing at 225 degrees rather than 215.  Don't know if this is a problem.

 calibration.JPG

The 225 is a problem, especially for materials like Galaxy Black.  But 225 will not cause or avoid a heat break jam.  Which is what I suspect you are experiencing.

Unload the filament, post a pic of what comes out.  Again - this must be a tip unloaded immediately after a jam.

RE: Multiple print failures

Resistance (rarely) can happen also on the other end of the rope, when the spool not moving correctly does block the filament move. I know it is stupid ,but happens. Hopefuly not in this case.

RE: Multiple print failures

@zoltan - For example, the latest dog print fail could be the heat break or it could be a frozen X axis.  There just isn't enough info to tell from the image.   We know the X was freezing up (shifting), and we know oil helped (higher BT numbers).  This latest fail may or may not be X (chances are lower now X appears better, but it is moving freely all the time?). 

The bothersome part with the dog in Galaxy Black is there are no signs the extruder was plugging up before the print was stopped. So we need to collect more info.

Hence my request for the filament stub image.

If the stub looks normal, then we check for other sources of filament resistance.   But seriously: we check ONE THING AT A TIME.  It is the only way to methodically find the root cause of a problem.

RE: Multiple print failures

@zoltan

Yes, I've checked the gear alignment and I think it is fine.  I did adjust it a while ago.  An allen key passes through the top piece and goes straight into the PTFE tube.

You are quite right - one issue at a time. 

I have now printed a perfect PRUSA logo - I didn't quite finish it, but its good.  I noticed that the nozzle temperature was fluctuating between 210 and 211 even though it is set at 215.

I am finishing for today.  Tomorrow, I will start printing one of my regular failures, and will sit by it noting the temperature.  I should also be able to see what happens at the point of failure (unless my mind drifts off, of course).

If (!!!) it fails, I will do as advised by tim-m30 - immediate unload and photo of the filament.

Big thanks again to all.    These online forums show the intrinsic kindness of people, who are willing to give their time and attention to complete strangers to help them out.

RE: Multiple print failures

Temps are never perfectly stable.  A fluctuation of 5c is not remarkable.  At layer 1 to layer 2, a 10c change when the print fan kicks on is pretty normal.  

Again - the next time it fails - that is no extrusion while printing - stop the print, do a normal unload filament.  Snap a clear photo of the filament tip.  If you have calipers, it is also handy to know the actual diameter of the stub, if there is one.

Here's an example of a stub caused by the Prusa heat break step.

Here is another stub from a jam caused by the heat break: the 2.20 to 2.00 mm step is clear.

The step is the inside geometry of the Prusa heat break, in the neck: 

RE: Multiple print failures

I am going to observe the whole printing of one of my regular failures tomorrow. I will note the temperature throughout and hope to catch the actual failure.  I will do an unload as you advise and take a photo.  I have a micrometer and will measure. 

Of course, Sod’s law might determine that it doesn’t fail!!!

RE: Multiple print failures

I do not abide by Sod, who ever that is.  But Murphy is my patron saint.

RE: Multiple print failures

Sods Law squared!

I decided to try printing the dog again as I know my machine can do this.  The printing time is 1hr 57 minutes.

I stayed beside the printer most of the time, and noted the temperature regularly.  When I left, I videoed the LCD screen with a camera on a tripod.  After 1 hr 54 minutes, it was still printing properly.  The initial nozzle temperature was 215 – required setting 215.  It dropped to 200 briefly, but after that varies between 209 and 211 with the required temperature being 210.

I left the room, and when I returned, there were 2 minutes to go, but the nozzle was no longer extruding even though the head was moving around is it should (I think).  I hoped to be able to retrieve the temperatures during the last few minutes fomr my camera, but it was frozen.  I’m not sure if it was still videoing, but the stop video, view image, on/off did nothing. (I as able to restore it by removing the battery but the video was corrupt).  So it seems I am cursed – this is the third machine failure I’ve had....  So I was unable to get the information about nozzle temperature when it actually stopped printing.

Anyway, I did a filament unload and am attaching a picture with dimensions.  So it definitely looks like a heat break jam.  I will try and post a picture of the top of the dog’s head where you can see that the printing seems perfect until it stops.

So advice about what I do next, please

RE: Multiple print failures

This is the  output - almost done!

RE: Multiple print failures

what layer height did you print? seems to me it had to be at least 0.2mm.

what is your ambient temperature, when printing?

I close window door in order to minimize air circulation. 

Did you recognize any tooth marks from bondtech gears?

RE: Multiple print failures

@epzcaw

can you please save the dog  project in 3MF file zip it and post it here?

if you have the g-code file would be also great to post it .

I will try to print it myself in order to make sure the dog is not infected by Sod.

RE: Multiple print failures

Unfortunately you are the winner of the heat break lottery.

https://www.amazon.com/Genuine-E3D-Break-1-75mm-V6-175-BREAK/dp/B077Y2MHW8

I have no clue why some printers have problems and other printers don't.  In my case I went months without issue then one day bam, constant jams.  Replaced the heat break and was printing again as if nothing was ever wrong.

I suspect it is wear inside the polished section of the heat break, that after some time and certain materials the interior surface gets scratched and becomes sticky to plastic. My problems started when I was printing glow-in-the-dark PLA.  They did not go away when I switched back to normal Prusa supplied PLA (or any other PLA I had).

Replacing the heat break is not that difficult. But usually requires removing the hot end from the extruder so you can grip the heat sink adequately to unscrew the heat break from the heater block and heat sink.

ps: when you install the new heat break, be sure to use good thermal paste on the heat break threads on only the heat sink side (longer section).

Good luck.

Or purchase directly from E3D, and buy the Titanium version:

https://e3d-online.com/catalog/product/view/id/9284/s/v6-titanium-heat-break/

RE: Multiple print failures

Posted by: @zoltan

what layer height did you print? seems to me it had to be at least 0.2mm.

Yes, is was .2mm

what is your ambient temperature, when printing?

About 22 degrees.  Have central heating on.  But probably hasn't changed much since I started even though it was summer. 

I close window door in order to minimize air circulation. 

No windows open - can close door but I dont; think there is much draught.

Did you recognize any tooth marks from bondtech gears?

Yes, I can feel ridges with my nail on one side of the filament

RE: Multiple print failures

@zoltan

Tried to send files but siad file-type not allowed.  Maybe I need to zip them?

RE: Multiple print failures

@tim-m30

If this is the problem, I will be greatly relieved that I've found an answer.  So I will order the titanium one, and hope that I can install it successfully.  Will keep you posted.

Thanks again

RE: Multiple print failures

@zoltan

You said zip file - I was not paying attention.  Both now in attached zip folder.

Note that I have printed this successfully several times. And the problem occurs with many different parts.

Tim is now sure is is a heat break problem and recommends replacing it, so I will go ahead with that,

Thanks again

RE: Multiple print failures

ZIP works, I am eager to print this enfant terrible who is making you such troubles 😉 

would you mind to try to print the dog with 0.15 mm layer? 0.2 mm in my interpretation means that the gears try to push by 25% more filament through the nozzle.

RE: Multiple print failures

When you do the install, just be patient, and follow the E3D assembly instructions to the letter: including the notes on how to ensure proper contact between the nozzle and heat break where the seal is actually made, and that loosening and final tightening of the nozzle must be done at temperature (280-285c). 

https://wiki.e3d-online.com/E3D-v6_Assembly

https://e3d-online.dozuki.com/Guide/Changing+Nozzles/45

RE: Multiple print failures

@zoltan

Most of my failures were on a different object - a 120x70x45mm box with some slots.  It failed time after time, but I did eventually manage to make it.  I'm attaching images of complete dog and complete box.

I think I will wait now to replace heat-break before doing any printing.