Worked for first 18 hours, then died

My printer arrived yesterday and worked for the first 18 hours... but the heated bed isn't heating anymore and the thermistor on the printing head just quit working as well and is giving a constant reading of 357c. I checked the heated bed connection and it has continuity but no power. The RAMPS board appears to not be putting out any current (I'm assuming it should be getting 12v DC) on the D8 connection.

The heated bed had been working, but died in the middle of a print. I had been printing, and I noticed it had gone silent... The printer LOOKED OK, then I saw that repetier was reporting that it was waiting for the bed to heat. ???! I thought... It was 20 minutes into the print, how did it cool down? That's when I killed the job and started to troubleshoot. The voltmeter seems to indicate that the problem is in the RAMPS. So, I thought I'd try and redo the print without the heated bed... well, it got 4-5 minutes into the job, and then aborted stating that the head was at a critical temp. I looked at the print, and it had only printed a little bit... I guess the rest of the time it was THINKING it was printing, but seems that the print head wasn't hot either as I was able to put my finger on the extruder tip and it was barely warm. I tried swapping the T0 and T1 connections to see if maybe it was the ramps or the thermistor, and it just changed from reporting that the print head was at 357c to reporting that the bed was 357c... so that implies to me that the thermistor died. I swear, I'm not doing anything wacky or trying to mod the printer or anything... just doing a backlog of prints I'd been waiting on the printer to do... and while I admit the printer has been quite busy for these first 18 hours, it has had downtime. I don't know if there is something wrong with the print head itself or what, but there seems to be minor amounts of PLA which have built up under the gold tape on the extruder. This seems to be coming from the head itself, and not from globs from failed prints or something... I could clean it out between prints and it'd be back again next time I looked, even if there was no problems with buildup under the extruder... most of my failed prints thus far had been to adhesion issues until I finally got that (mostly) sorted out.

I don't know what to do at this point. I've only gotten two successful prints thus far... the Mr. Jaws test, and the DTI bed lever... I was in the process of printing a endcap for the filament holder... as there wasn't one, and was getting ready to queue up the next print which was NEMA23 brackets for a CNC router for my buddy. Now I'm completely dead in the water.

Matt in Dripping Springs, TX
Kicker #325

 

Ahhh didn't see that section. I'll go open a ticket there.

 

Just to provide some follow up as to the status of my printer. 1) The thermistor in the print head failed. I've also got a problem with the print head "leaking". Robo is sending me a new hotend and that should be a resolution for that problem. The theory is this is also what is causing the heated bed to not power up. I'm not 100% sure on that, but am willing to give it a try and see if that resolves things or not. Might be a firmware issue for safety where if the hotend is giving a crazy temp then the heated bed won't power up. I'd tried swapping the T0 and T1 connections on the RAMPS to "move" the 357c temp from the head to the bed, as well as disconnecting it and NOT having a thermistor connector to RAMPS for the bed temp to see if I could get the bed to turn back on, but at that point I'm outside of the norm enough (turning on a device without an attached thermistor as far as RAMPS and the firmware can see) that it not working isn't something I REALLY expected to work anyway... Apparently others are also seeing issues with the heated bed failing, so they suspect it's a firmware issue and are investigating more... I'll do my best to assist in that once I have my print head working again.

So, I'm awaiting parts and have my ROBO torn down in anticipation of their arrival.

Breaks my heart to see it sitting there in pieces after having waited SO long for it's arrival... but am happy to see the support guys at ROBO being so responsive.

 

Not leaking from the hotend, leaking ABOVE the hotend. It's leaking from the PEEK connection to the hotend. It completely filled every crack and crevice under the tape, and I would have to squeeze it out with a tongue depressor between prints... and is a TOTAL mess. I got it apart, but had to disassemble the whole top axis to do so. Getting the hotend off the PEEK connection with all that now frozen in place PLA was NOT fun... much hacking with dikes and a pocket knife was required... I managed to snap one of the connections to the heating resistor in the process. With the new hotend on the way I'll just have to see how it goes. I'm not sure how to get the PEEK connector off with if filled with the PLA. I mean FILLED! It's a damn mess is what it is. I'll figure something out tho...

This may have been what burned out the Thermistor. Not sure... the end looks burnt, but I've no idea what it's supposed to look like new, much less after 18 hours of use... but it don't work no more! I was successful printing Mr Jaws on my 2nd attempt... then I started trying to print the thingaverse robo3d bed leveler to hold a dial test indicator to assist with leveling the bed. That took a while to print out... as I kept having delamination issues. Finally I printed it with honeycomb support and a raft and THAT stuck and printed successfully. Then I started in on a set of NEMA24 support brackets, got 7 hours into the print, opened the door for the dog and dropped ambient enough that it got all screwed up... Bah! On the next attempt to print it, the heated bed died and kept delaminating. I finally got it to start printing with the bed off, and then the thermistor in the head went kaput and I was dead in the water...

 

As you can see in the photos... it wasn't leaking at first... my guess is as the thermistor was dying, and giving false readings, the heating element went into overdrive, and damaged the PEEK connector. Once that was done, it started leaking, and overheating the PLA... you can see on the "Robo-1" photo it was getting really bad globs of almost black PLA... that was when I was out of the room tho... so I don't really know what happened or when. I just came back upstairs to check on it after an hour or so, say the print was spoiled, closed the door, cleaned the bed, and tried again... as everything started to fail in successive ways until I couldn't do anything but contact support with "Help, the printers broken!"

 

It's not oozing I'm talking about.

The connection BETWEEN the PEEK and the hotend is what was leaking. That then flowed down into the hotend and under the tape and would drip and glop onto the print with half marble sized "drips" as the amount of PLA would build... unless I squeezed out the pla between prints (or frequently during my long print prior to the thermistor dying. Look at the photo above for the "Robo2" and "Robo3". Ignore the oozing. Look between the nozzle tip and the PEEK. Notice the hotend is caked in blue PLA. Notice the threads of the hotend are blue. That's the leaking. My guess is when the thermistor started to die, it allowed the hotend to become overheated, and melted/damaged the PEEK enough to allow the leaking.

 

Support is sending a new hotend, as well as more kapton. I -think- they are sending a new peek connector as well as the internal tube in there... not totally sure what all the parts are there as mine is such a mess. There was a theory of a set screw not being in place which caused it all to start. Dunno. I'm still trying to get the PEEK connection off. It's STUCK STUCK STUCK from all the molten PLA. I'm gonna work on it more this evening. I've gotta hook the brush hog up to the tractor this AM and mow the ranch, and then get back out to the shop and try and get my CNC foam cutter finished up... we're building linear bearings to construct 3 different CNC routers and a plasma cutter table. The life of a machinist/fabricator. Always between 3 and 2,547,385 irons in the fire.

 

I believe I am starting to have that same problem. I started noticing it because the plastic (PLA) would stop threading through the nozzle after the first initial layer.
I have attached photos and will try to retape it and see if it helps. Any other advice is greatly appreciated. Thanks.

 

What are you using for setting your Z spacing? You are setting both sides individually (and holding the rod so you don't adjust the opposite side) yes? What is your temp for the second layer vs the first? You may be lowering the temp too much for the second layer so that could posibly cause that. For the second layer as you watch the temperature of the print head hotend is it staying at the temp you set it to be at?

Looking at the top of your hotend betwen it and the PEEK nozzle holder doesn't appear to me to have leaking under the tape, but that may just be the photo. Are you using black filament or is that burnt blue?

 

I used a business card in all four corners to adjust the z spacing while holding the rods to adjust it. My temperature is at 190 for the first and I adjusted the second to 190 after seeing a similar post when it first started happening. The print head temp drops maybe a half a degree when printing at most.
I am using black filament so yes it is difficult to see, but it has been pooling up in the bottom right corner by the tape.

 

You might try tightening the hotend into the nozzle holder once everything is up to temp. You need to be a bit careful because at those temps it should be able to strip the threads on the holder if you tighten too much. That MIGHT stop the leaking. You'd need to do it while everything is up to temp in case there is the (now molten) filament in the holder/tube which should spooge out while you tighten the hotend. I would say to do this ONLY if you are seeing buildup of material on the threads meaning it's leaking from the connection between the nozzle holder and the hotend.

 

It looks like it is leaking from inside the tape then pooling up. I tried another print and it was able to print the entire job but the build up seen in the picture fell off at one point onto the print and I had to try and remove it.

 

Just to follow up for anyone interested. My replacement hotend arrived via FedEx (Saturday Delivery even!!!) this morning. My printer is reassembled, and printing again! Total time from initial report of the problem, to fix in hand and printing again, has been from October 22nd to today, November 2nd. A total of 12 days. Not complaining, just reporting my experience.

I've started in again on the 12.5 hour print that killed my printer previously... so far, so good!

 

Another follow up:

I managed to screw in the end and stop the leaking, but have run into a problem with printing that I was wondering if anyone here may know how to fix. My first layer does not come out well and there are lumps that form. Many times when the printer head moves back over them it will rip the print off the bed and ruin the print. I have changed many different settings trying to fix this but I can't seem to get it. Any and all advice is appreciated. I have attached a picture for reference on one of the parts.

Thanks

 

I've had that as well. It's the first layer proximity to the hotend so that means leveling and/or Z endstop adjustment. Try screwing the Z axis endstop screw in just a touch more. Also remember that the clearance changes between when the head/bed are cold and hot. Thermal expansion doesn't take much to close that gap. Also you may try adjusting your first layers height via the setting in Slic3r -> Print Settings -> Layers and perimeters -> First layer height. I have mine set at 130% which seems to be working pretty well... The first layer for the perimeter on your photo looks great, nice a flat... so maybe try ramping down your first layer height a little bit maybe if it's set higher than 130% or try going back to 100% or maybe even less. What all have you tried for settings and experiments to avoid the issue? Also, how do your 2nd, 3rd, and 5th layers work out? Is it just the second layer that's getting drug through?

 

When you say put the Z endstop in more, you mean to raise the print head, correct?

Mine was set at the default so I will try and adjust it now. My first and second layers were the only ones really having the problem. All the rest seem to come out fine. Even when doing the 15mm calibration cube everything comes out perfect except for the first layer or two. I had previously tried moving the temperature around a few degrees thinking it was excess filament coming through and played with the fan settings to try and cool it during the first layer and not bunch up.