Massive filament blob.

[Jason Preuss]

So I finally got my rep2 working well. With the mk8 upgrade I completely stopped having print failures from filament feeding problems. Then this morning I started a print before work and came home to this.

I'm guessing that some piece of filament got caught on the extruder and just keep accumulating for 2.5 hours. I can't believe it didn't just clog up at some point (maybe the mk8 upgrade is too good). Anyway I have a very serious problem now. The entire heater/insulator/lead wires are completely encased in hardened plastic. I think I am going to have to get my Dremel out and hope for the best. Maybe Makercare would have been a good idea...

[Eighty]

Ouch. But if it makes you feel any better, Makercare probably wouldn't cover it due to the mod...
I wonder if preheating the Bot would help you get it off of the delicate parts. At least soften it a bit.

[Avandss]

wow, thats intense! what bad luck, i wonder how it got that bad

[Avandss]

btw what were you trying to print? lol it will go on my dont print list... j/k

[Shawn]

No panic - yet. I see this type of behavior occasionally. Not normally
quite THAT large though. For me it is always accumulated around the
nozzle (knock on wood), so I just have to preheat the nozzle and pull
the crud off.

In your case, I would see if I could disassmble the mass from the
carriage. Then take a heat gun to the mess to see if the wires can be
extracted. (you don't want that much heat around the carriage and
possibly melting or damaging it)

I can honestly say that this is the first time I've seen a failure that
has actually damaged a Replicator, or at least has the potential too.
Every extreme failure I've seen before is "just" a mess to throw in the
failures box, and then start printing again.

Good luck!!

Shawn

On 12-12-14 05:52 PM, Jason Preuss wrote:
> So I finally got my rep2 working well. With the mk8 upgrade I completely
> stopped having print failures from filament feeding problems. Then this
> morning I started a print before work and came home to this.
>

> <https://lh6.googleusercontent.com/-OpiWBJK37K4/UMvIBRuNd5I/AAAAAAAAAAM/Ui-uJvvIXeo/s1600/2012-12-14+15.52.10.jpg><https://lh6.googleusercontent.com/-lKTBqLZzKg0/UMvIeDpmXoI/AAAAAAAAAAU/M3Vy0jnnTKk/s1600/2012-12-14+17.11.14.jpg>

>
> I'm guessing that some piece of filament got caught on the extruder and
> just keep accumulating for 2.5 hours. I can't believe it didn't just
> clog up at some point (maybe the mk8 upgrade is too good). Anyway I have
> a very serious problem now. The entire heater/insulator/lead wires are
> completely encased in hardened plastic. I think I am going to have to
> get my Dremel out and hope for the best. Maybe Makercare would have been
> a good idea...
>

> --
>
>

[randyzimmer]

Looks like the nozzle came loose from the threaded barrel.

[whpthomas]

Jason,

I suspect that your work piece has dislodged from the build plate and then been dragged around by the extruder and gradually melted into the nozzle and been dragged around as progressively more and more filament has been extruded. Let us know how the cleanup goes. Shame in this case that the filament didn't jam - I suspect a heat gun will be necessary.

[Z LeHericy]

heat gunning it should be a safe way to remove that, pull off any parts (of the extruder) that you can, otherwise most of it is rated to high temps for extrusion, so you shouldnt have to worry too much about heat hurting it

-Zeno LeHericy

//((=:Z:=))\\
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On Fri, Dec 14, 2012 at 8:01 PM, whpthomas <m...@henri.net> wrote:

Jason,

I suspect that your work piece has dislodged from the build plate and then been dragged around by the extruder and gradually melted into the nozzle and been dragged around as progressively more and more filament has been extruded. Let us know how the cleanup goes. Shame in this case that the filament didn't jam - I suspect a heat gun will be necessary.

--
 
 

[Jason Preuss]

I hadn't thought of the heat gun, that's a good idea. I'll probably dremel off the part of the blob that is away from all the other parts and then try the heat gun. Unfortunately since the plastic has been pushed into crevices and completely encased the wires leading into the heater I can't just heat it up and pull it off (already tried).

It is clear that it did catch part of the print, picked it up, and the snowball effect was on.

[whpthomas]

Jason, my commiserations - but thanks for sharing this is obviously something we need to be mindful of when we leave our bots singing away unattended. It is a delicate balance between making sure the part is sticking to the base plate, and it not sticking so hard that it breaks when you try to pull it off. Right now I am letting my Rep2 do the base layers and a good 10mm of build or so, then doing cold pause and checking the base does not have bits that have separated - all this before I leave it unattended. My new caution is based on your experience - so thanks.

[Jason Preuss]

I worked on this yesterday and it doesn't look salvageable. First is the massive amount of plastic. Every tool I had bound up in the mess (you start cutting away, the plastic starts to melt, instant gumming up). Because it is so intertwined a heat gun isn't going to work because I would be melting other things besides the PLA. Finally after further examination I see a lot of insulation embedded in the plastic blob meaning that most of the insulation around the heating element has probably been stripped away. So even if I got all the plastic out I still don't think it would be safely functional. I have sent off a ticket to makerbot, I am expecting an expensive repair bill and to be out of commission for a while. There goes my Christmas break plans.

A very small silver lining - for those who are worried about printing the extruder upgrade in PLA and wondering if it can withstand the heat I can't imagine a better stress test then having the entire heating element encased in plastic and printing for over 2 hours and the upgrade part having no problem at all.

[c f]

Have you tried just chiseling, rather than using a rotary cutting tool? PLA is fairly brittle, and the 'interface' between the injection molded parts and the PLA is probably pretty poor. The heater block on my ToM just has a few cents worth of ceramic tape around it for insulation (taped together with some kapton).

On Sun, Dec 16, 2012 at 7:12 AM, Jason Preuss <jmpr...@gmail.com> wrote:

I worked on this yesterday and it doesn't look salvageable. First is the massive amount of plastic. Every tool I had bound up in the mess (you start cutting away, the plastic starts to melt, instant gumming up). Because it is so intertwined a heat gun isn't going to work because I would be melting other things besides the PLA. Finally after further examination I see a lot of insulation embedded in the plastic blob meaning that most of the insulation around the heating element has probably been stripped away. So even if I got all the plastic out I still don't think it would be safely functional. I have sent off a ticket to makerbot, I am expecting an expensive repair bill and to be out of commission for a while. There goes my Christmas break plans.

A very small silver lining - for those who are worried about printing the extruder upgrade in PLA and wondering if it can withstand the heat I can't imagine a better stress test then having the entire heating element encased in plastic and printing for over 2 hours and the upgrade part having no problem at all.

--
 
 

[Joseph Chiu]

Since you're willing to write it off at this point, I'm wondering if you might be willing to dunk that block into a pot of hot (or even boiling) water -- That should get hot enough to soften the PLA that you could work it loose.  I would guess the ceramic heater and the thermocouple should be fine with the dunk as long as you completely dry them (and then be paranoid and dry them even longer) before putting them back into operation.

--
 
 

[Joseph Chiu]

BTW, I just have to mention that I was hearing a cooking-show voice in my head saying: "be sure to sous vide your extruder in a well regulated water bath for 4 hours"... :)

[Joseph Chiu]

Sorry for yet another fast follow-on post...  Could you possibly carve it with a heavy-duty (200W - 300W) soldering iron or gun?

[Jason Preuss]

I contacted makerbot support and he suggested one more thing to try. I could not from the bot get the heater to turn on, reheating the plastic being the easiest way to remove he. He reminded me that I can control the heater through RepG. It took awhile but I was able to get control of the bot, preheat it, wait 30 minutes, and was able to get the blob off. This was late last night so I have not reassembled and tested to see if it works. The filament blob did rip off all the insulation from the side and the bottom. Anyone know if I can run the bot without that in place?

[Z LeHericy]

it's not suggested to run without insulation, but when I bought my MK7 extruder, i lost the ceramic fabric, so I just wrapped the extruder in extra Kapton and have been using it like that ever since

haven't had any issues other than it taking a tiny bit longer to heat up (but that doesnt matter since it's still faster than my HBP which has a 1/4 inch slab of aluminum on top)

-Zeno LeHericy

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On Mon, Dec 17, 2012 at 8:06 AM, Jason Preuss <jmpr...@gmail.com> wrote:

I contacted makerbot support and he suggested one more thing to try. I could not from the bot get the heater to turn on, reheating the plastic being the easiest way to remove he. He reminded me that I can control the heater through RepG. It took awhile but I was able to get control of the bot, preheat it, wait 30 minutes, and was able to get the blob off. This was late last night so I have not reassembled and tested to see if it works. The filament blob did rip off all the insulation from the side and the bottom. Anyone know if I can run the bot without that in place?

--
 
 

[Z LeHericy]

Mind you this is on a Gen4 Cupcake, where you're on a Rep2, but the Mk7 and Mk8 extruders are very similar.

-Zeno LeHericy

//((=:Z:=))\\
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zinventions.com

[Jason Preuss]

Well here it is, 29 days after it first failed causing the massive blob, I have finally printed my last plate for Emmet's Automatic Transmission.

In the end it took separate parts replacements for the insulation and the thermocouple and a ton of back and forth with MBI support by my machine is back in action. I'll never get the time I planned to print over the holidays back but at least I'll have something to show my maker group next weekend.

While the support with MBI was slow (the timing with the holidays was terrible) in the end they did right by me.

[whpthomas]

Its very heartening to see these results after everything you have been through - well done.

[Toby Evetts]

My first reply didn't seem to go up so here goes again. 

I had the same problem just before Christmas.  A huge orange blob that separated the thermocouple so I couldn't heat it off and I had to cut it out as best I could and then heat it with a blow torch. Makerbot send me a new hot end so I had to learn to pull everything apart and replace it. Seems to work fine now but I don't like leaving it for long prints. I've also gone off orange filament. 

Despite the annoyance and the scare it was a good lesson in getting to grips with how it works and not being afraid to hurt it. I'd like to have more spare parts around though. The thermocouple they sell on the site is not the same as the one in the MK8 hot end which has it's own metal bar that goes into the aluinium. Does anyone know where to buy other spare parts like the screw guide for the filament as spares? 

[Jetguy]

The thermocouple for Replicator series is Type K Thermocouple (MP0138)
That's MakerBot's internal support part numbering so just contact
support, say you need one or two of those and they will help you get
it. FLY same price oas the other ones $16.

On Jan 18, 5:13 pm, Toby Evetts <t...@chemicalwedding.tv> wrote:
> I had exactly the same thing happen to me just before christmas. A huge
> blob of pla but in my case the thermocouple was disconnected by the blob so
> I could not bring it up to temperature to melt it off. I did eventually
> manage to get it apart and MB sent me a replacement hot end. That meant a
> lot of rolling up sleeves and swearing to try and figure out how it went
> together again, but it now works. I'm now very nervous leaving it to print
> for long periods of time and a bit like food poisoning I'm averse to the
> orange PLA I was using at the time. The good news is learnt to take the
> whole thing to pieces and rebuild it which has made me more comfortable
> with mods in general.
>
> Makerbot sent me the replacement hot end but I'd quite like to have a few
> spares lying around in case it happens again. Does anyone know where to buy
> things like a replacement thermocouple (it seems to be different from the
> type K they have on the site) and the filament screw that guides the main
> filament. (I have a MK8 rep 2). I'd really like to be prepared.
>
>
>
> On Saturday, January 12, 2013 4:44:09 PM UTC-8, Jason Preuss wrote:
>
> > <https://lh3.googleusercontent.com/-o8q504bBrJ4/UPICubcnTII/AAAAAAAAAB...>

> > terrible) in the end they did right by me.- Hide quoted text -
>
> - Show quoted text -

[Toby Evetts]

Well I wasn't sure about that because on the MK7 the thermocouple screws to the outside but on the MK8 it seems to go inside the little aluminium block. Is it the same thermocouple. if so what the bit it goes inside?

[Wingcommander whpthomas]

I tend to only leave things unattended that are big and have a well anchored base, or if they are small items I print a lot of them so that if one beaks loose it will get cleared off the nozzle by the presence of the others - which has happened - you do end up with spaghetti noodles of filament all over the nearest parts, but at least no filament blob to clean up.

[Jetguy]

The bit that goes inside is the heater cartridge. Notee that on
Replicator series it is 24V so you need to go to support and ask. Do
not buy the one in the store as it's 12 volt for T-O-Ms.

Also note that you can get one in 24 volt from QU-BD for cheaper than
the $28 Makerbot charges.

[Toby Evetts]

On mine there are two. The heating cartridge goes in one hole and the thermocouple into another. as far as I can see the mk7 thermocouple is held in place by a screw on the outside  but mine is embedded in a smaller metal pin that goes into the block. Unless I'm missing something.

[Jetguy]

Ok then they went to an Ultimaker style setup. Again contact MakerBot
support, get the right parts for your bot.

[Jason Preuss]

My mistake was I left for work before the entire first layer was done. I feel pretty confident that after the first couple layers are down the massive blob is very unlikely. I did have to run the heater quite a bit higher than the 180c they recommended to free the blob (I think 240c finally did it).

I did learn a ton about my bot having to tear it almost completely apart to replace that thermocouple which I guess isn't a bad thing.

As a final note my machine is now running as well as it ever has, I recently completed a 14+ hour print (mostly unattended) that came out great.