Alien Egg...

Last night I set up a printing job which will run over 3 hours.

Started printing and watched the first few layers to make sure everything is looking good and going well.

Turned off the light, left the room, and went to bed to sleep.


This morning, this is what I have found:



Yeah.. holy crap...

Now I'm heating up the hot end to take this thing off.

I just hope I am not gonna see some alien bugs crawling out of this thing...

Oh what a waste of plastic by the way

Edited 2 time(s). Last edit at 09/20/2013 07:44AM by Yamster.

I just sort out PLA bits into a bag whenever i feel it isnt too much effort to do so. I dont plan on getting a recycler, but I hope someone in the neighbourhood, or maybe a hackerspace will eventually get one.. (dont know what issues there might be with contaminations in the stuff)

You have any idea what caused it? Could be detachment, the head crashing into little extra bits..

Looks like your hot end is pretty worthless.

Getting PLA all over the place is fixable, just take it off, and this problem could be caused by other things. What is the white stuff? Just the stuff that holds the thermistor, heater resistor in?

The white stuff is Teflon tape - I put layers of it around the nozzle head for insulation.

There are a couple of things which caused this plastic "tumor"

1) On of the screws, which hold the heated bed down (I have spring suspensions between the heated bed and the bottom plate), came loose and completely got disengaged. This caused the heated bed to come up quite a bit and caused the hot end run into the printed objects and knock them down. After that it kept on running squeezing out melted plastic against nothing.

Well, this is all speculation since I actually didn't see any of it happening (I was in sleep), but all the evidences are there. Although I didn't include them in the picture, besides this big blob, there were piles of plastic ramen noodle all over the place.

2) The hot end temperature was set too high. I had it running at 200 C, but apparently that was a little too high. I was able to print quite a few objects at that temperature, so I didn't bother to adjust it, but there were some tell tell signs of it being a bit too high. When the temperature is too high, I believe the melted plastic tends to be more "gooey" and sticky as well. As a result, sometimes they form blobs right at the nozzle tip (of course, normally not this size) instead of coming down as a line.

After cleaning up, I was able to print again, but this time I set the temperature at 185C. Looking back, I should've lowered the temperature before all this - after all, I think lower temperature (but still in the operating range) gives me a better print results especially with overhangs and bridges.


The clean up was not too hard. I just heated up the hot end, and was able to remove the most of it in one snap. It tore the Teflon taping a bit, so I just had to remove them and put new tapes.

The shake up must have been very violent, that it did not only knock of the printed objects but the glass plate as well. Thanks to the carpeted floor, the glass didn't break.

Despite all this, there seems to be no real damages. I was able to print things after the clean up - I didn't even have to level the bed!


Well, this is one of the downside of overnight printing... If I was there, obviously I would've stopped printing at the first sight of trouble.

Actually, I wonder if there's some kind of vibration sensor I can install on my printer to monitor malfunctions/print issues like this (which causes more than normal level of vibration). I saw a setting for vibration limit on Slic3r. Is there such thing?

That's pretty much why I don't like to do long unattended prints. I can imagine all kinds of failures that would end up much worse than what happened to you.

sheck626 Wrote:
-------------------------------------------------------
> That's pretty much why I don't like to do long
> unattended prints. I can imagine all kinds of
> failures that would end up much worse than what
> happened to you.

I cannot disagree or object to this at all. But then again, a lot of times I don't have any other choice but to do it.

So far, this alien egg/tumor thing was the worst case I've had when an overnight printing had gone wrong, so I guess I must have been lucky... *knock on wood*

For overnight prints, whenever one has fails I always wake within a few minutes before any serious damage occurs. The printer is in the next room but I have no idea what causes me to wake up as it wouldn't look like it had made a big noise or anything like that.

When I'm away from home and leave it printing I keep an eye on it through a webcam, checking as often as possible and stopping the print if anything looks amiss. I would never leave it printing for hours without checking at least two or three times an hour - a printer can cause itself a lot of harm if things go wrong.

Mostly the failures I've had are detachment from the build plate, filament getting tangled at the reel and feline intervention.

Haha.. feline intervention. Maybe you can train your cat to turn off printer for you when something goes wrong with printing while you are away. :p

By the way, web cam monitoring is a good idea. I guess you must have some kind of home security/automation system? You know, so that you can also stop the printer by turning the power off when you see a problem.

No special setup needed - I just use Logmein from my phone (or a PC if there is one nearby) to access the PC at home and just click the stop button on ReplicatorG, which I leave connected to the printer all the time.