Extruder Problems, Replicator 2 - OMG - I found my issue!

[David Mytchak]

I received my Rep2 in late October and had GREAT prints - worked freaking well.  Then came December 12th.  It went south and went south quickly.   I've had leaky extruders, MK8 Modification, 4 spools of PLA from different suppliers - you name it, I tried it.   I couldn't get a good print to save my life - like many of us on this forum.  It just wasn't working.  AirPrints in about 10 % of the build, etc.    I even replace my extruder out of my own pocket from the one from QU-BD (they sell a MBE replacement - looks like the same one MBI uses).  Anyway, prints that use to print were not even printing.  So yesterday, after reading posts from both Dan and whpthomas (both of which are great guys) and reading that both of them are PhD's, If two PhD's can't figure it out, I'm doomed. I was about to throw in the towel with Makerbot.   So I grabbed some coffee and sat thinking about returning my once loved Makerbot Replicator 2.  I was really bummed.   As I sat pouting with my coffee it hit me.  I've tried everything with degrading results and when I reverted back to the original extruder, I had the same, nozzle jams.  I read about lowering the temperatures and have tried all temps from 190-230 all resulting in bad prints.    BAM- I'm assuming the temperature is accurate.  What if my 230 is really 190?  I doubt it but it was worth a try.  So I pull out my trusty Flir and sure enough - the Rep2 is reporting higher temperatures than actuals.  So I changed my geode to set the extruder temperature to 242 C and printed.   100% Success!  I've been dicking with this several weeks with 100% failure rate thinking it was everything from bad PLA to planetary alignment.   It looks like the heat sensor has lost its sensitivity over time.

If you're having the nozzle stop on you mid build, you may want to try cranking up the heat rather than decreasing to see if it helps.   I'm attaching my thermograms to show the results - the temperature on the bot was set to 242 C.  Page was shows the heater block at 211.6 C and page two shows the Nozzle temperature at 148 C !    Reflectivity has been set for both the insulation and the brass nozzle.  Increasing the heat solved my issue. So in short, I'm seeing 211.6C when I set my bot to 242!  

I'm off to update my ticket with MakerBot but so far, I've made HUGE progress by simply increasing the heat.   

I hope this helps!

-David

 

[Mark Durbin]

I always set my temp to 240, I started at the same time as I tightened the grub screw, when it worked I assumed it was the grub screw, but not wanting to pull any more hair out, I have always printed at 240 degrees, 120mm/s ever since.  

-David

 

--
 
 

[David Mytchak]

I'm printing at 80mm/s at 240 and want to get the bot into a stable mode before pushing to 120mm/s.  I'm going to use another method of measurement since the Flir is very sensitive to reflectivity of the object being measured.  Back to good ol' Mercury...

Thanks for the feedback!

-David

[Darrell jan]

Congratulations! Hmm. How much does one of those Flirs run?

Darrell

[whpthomas]

Hi David,

Really glad you got your rep 2 working again. My experience was the opposite, but similar in some respects, we had over a week of hot high humidity weather here in sunny Queensland, and I believe my problem was overheating. Maybe in winter up north you guys are having the same problem but with the cold. I started to see that heat was in face monetarily moving up from the element to the cooling block, and causing the filament to bulge and jam. Once deformed no amount of extruder pressure was going to keep that filament moving. I purchased a 40 x 40 x 10 south bridge type heats ink, and used adhesive thermal compound to affix it to the back of the extruder stepper motor. Then I got some thermal gasket to isolate it form the cooling block. The making the plunger was just tight enough not to strip, but still turning freely by manually turning it, I dropped the print temp by 2 degrees c and my jams stopped. Went back to 230 and it jammed, dropped it back to 228 and the next print worked. Previously I had been stepping temperatures by 5 degree increments, and had not realised, that only small changes could have such an impact. Then the prevailing wind shifted to a cool dry southeast pattern and my bot is back to printing without a hitch. I suspect that the temperature sensor in these printers is not as accurate or reactive as we think and outside conditions are changing print results. Alternatively you hypothesis, that they are degrading in so me way over time may also be valid. Maybe a bit of thermal compound around the sensor might help its accuracy. When I get back home tomorrow I will give that a try. Thanks so much for sharing your results.

[whpthomas]

Sorry for my grammar, typing on my iPad and autocorrect is playing havoc as I type :(

[David Mytchak]

High Humidity?  I'm in Houston  where the relative humidity is normally higher or equal to the temperature.  Right now it's 100% - bleh!

I ripped the heat sink out of my extruder.  In fact, I i reversed the fan direction to where it's blowing directly on the aluminum bar that holds the extruder and tube.   I insulated the extruder and the air flow below the extruder mount so that the hot end remains hot while cold air is blowing on the the bar.   I used a ceramic sheet used for gasket making (you can buy one from Autozone) and it seems to work really well.   I did however have a bad print last night so I'm not 100% out of the woods.  However, I am much further than I was over the weekend.   This blob you mentioned raise my eye brows.   I too receive the 'blob' which is about the same length as the nozzle during a jam while printing at the lower temperatures.   Perhaps the nozzle length is too long?   I think I'll buy some hex brass and put it on my lathe to make a custom nozzle to see if that helps.   I hate machining brass and avoid it like the plague since it spews splinters on the lathe rather than a nice curly string but this maybe one case where I make the exception.   

This is my 1st go at 3D printing and to say (not new to machining and CNC), it started out great but turned into a full time job just to get the bot pseudo working again.   It seems that the MK8/7 has been around the block and I am surprised that we're seeing these problems with the current design.   I expected some fiddling with the settings and such but not a full rebuild (several times) of the extruder.

Okay - off my soap box.    I'll print some more tonight and reply to the thread.   

Thanks for all the support!

-David

[David Mytchak]

Darrell,

You can get them for around $2,000.00 USD.   It's a great tool but you have to know a thing or two about thermography (which I'm learning - not my day job ;) ).

-David

[Alex Lau]

Think I might have a similar issue:

Here are my results from experimenting last night..seems higher temperatures are working better for some reason..

https://docs.google.com/document/d/1arTU0PgSgB14xcWBAfrZx-NVRMX-LAMPplltMPGg0ec/edit

[whpthomas]

I just stuck a temperature probe on mine, poked the tip up between the edge of the nozzle and the insulation, after 5 minutes on preheat, the temp on the bot was 230c, and the temp for the probe was 227c. So not a huge difference - nothing like what you were seeing. The 3c difference may be a consequence of the thermal contact not being perfect, no compound, and the tip was just pressed against the metal.

[whpthomas]

I just changed rolls to clear PLA, and have had one failed print after another - GRRRR. Tweaking settings, trying different packing densities, temperatures, etc.

The extruder would just keep jamming, click click click. I would pause the print to do a filament re-load - but the filament was always jammed - I would have to unload, snip and reload. And each time had a look filament end I pulled out, and it really seemed OK. No big blob, no air bubbles, just straight filament leading into the stretched bit where I pulled it out.

So I though, this is 1.75 filament and the weather is hot, maybe its swelling a bit - I measured it with the digital callipers and its measuring 1.8mm - so how big is the tube in the nozzle it goes into? Maybe its just jamming, maybe it needs a bit of lubricant to help it if it is. So I did something I would have otherwise have considered stupid if I were not so fed up - I got some PFTE grease, lubed a good 2" of the end of the filament and then reloaded it. For the first time this morning, its printing - go figure.

Is greasing the filament tip a bad idea? Its high temp synthetic PTFE grease, so my guess the fumes are not so good, but it seems to have gotten my fussy extruder going again.

[Dan Newman]

On 11 Jan 2013 , at 8:21 PM, whpthomas wrote:

> I just changed rolls to clear PLA, and have had one failed print after
> another - GRRRR. Tweaking settings, trying different packing densities,
> temperatures, etc.

FWIW, I avoid the clear PLA I received with my Rep 2. It's somewhat
uncooperative. That may just be me or my small spool. Dunno. From
time to time I get plastic that doesn't behave well for me and rather
than waste too much time, I just use a different plastic. (I'm also
not fond of the white PLA, but we've come to an understanding, that
spool and I.)

> Is greasing the filament tip a bad idea? Its high temp synthetic PTFE
>
> grease, so my guess the fumes are not so good,

Well, they are toxic, but probably not enough to do any damage.
My bigger concern is what sort of deposits might it leave within
the extruder.

Dan

[Clinton Hoines]

Nope I agree, when I bought my Replicator I got 3 rolls of clear with it as that is all the place in Canada I got my bot from had. Every one of those rolls is tempermental to say the least. I still have most of a roll left, only used most of the first two waiting for other colors to come in. The clear is by far the largest PITA to try and extrude.

 

Clinton

[whpthomas]

My black sheep are the white and clear reels - always the trouble makers.

The grease I use is not actually the PTFE from Makerbot, but one made by inox (http://inox-mx3.com). Its high temp compatible (rated up to 260c) so may not even fail at printing temperatures. I only put a very thin smear on, but just thought I should share this experience with others - the random jams are very frustrating.

[Jetguy]

It's not like PTFE fumes are toxic? They say it only happens with with
temps higher than what we run, but at the same time, you're putting a
probably fine powder version suspended in an oil or other chemical
that likely boils and carries the PTFE with it into the air. I mean if
you put it in, it must go somewhere right?

You could use the bird test but that's animal cruelty http://424pets.com/fumes.html

Somehow, even if it's not toxic to the point it causes problems it
seems like a bad idea. Also, what about interlayer bonding? Stress
cracks in printed parts?

Just saying, Cancer has hit several members of my own family, it
doesn't seem worth the even remote possibility to introduce risk over
what would seem to be a bad idea anyway.

[Z LeHericy]

PFTE is carcinogenic, and begins outgassing around 250C, but is not reccomended for use over 225

-Zeno LeHericy

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

--

[whpthomas]

PFTE is carcinogenic, and begins outgassing around 250C, but is not reccomended for use over 225

OK hand officially spanked - I did say in my original post that I thought it was a bad idea - even though my printer continues printing clear PLA without a hitch. Maybe there is some other lubricant that could be used - it was the tiniest amount. 

[Clinton Hoines]

I've read a small amount of Olive oil has been used by some, I have not had to so this is just what I have read on the subject.

 

Clinton

[whpthomas]

I already use olive oil on my acrylic build plate, to adding some to the extruder intake isn't going to feel out of the ordinary :)

Thanks for the tip

[whpthomas]

I have to say, after print after print on clear PLA failing this morning first layer, I have just had 3 x 4 ~ 5 hour prints go of without a hitch. Could it really be that easy that some sort of filament lube at the start of a print can fix jams?

[Joseph Chiu]

With my experiences with jams, it seems that some amount of plsatic ends up forming a solid chunk that secures itself to the tube wall, prevent any further feeding -- so having some kind of lubricant that prevents it from sticking to the wall makes sense.  Like others, I'm a bit worried about the downstream effect of putting anything in there, though.  

On Sat, Jan 12, 2013 at 7:03 AM, whpthomas <m...@henri.net> wrote:

I have to say, after print after print on clear PLA failing this morning first layer, I have just had 3 x 4 ~ 5 hour prints go of without a hitch. Could it really be that easy that some sort of filament lube at the start of a print can fix jams?

--
 
 

[David Mytchak]

Good to know about the clear PLA - it's been giving me trouble all day and was thinking that I was back at square one.   I'll give blue a try.

Anyone want a roll of clear PLA?

[Eighty]

You couldn't pay me money to take it. Have the original 1lb, plus a 1kg spool, and refuse to use it anymore. It's the only filament that has caused me problems that I can't trace back to my own stupidity. I've found that it varies by as much as 0.30mm in diameter within a few feet.
Not to mention, it's ugly...

[Darrell jan]

I have "natural" PLA, bought from Amazon. Is this the same as clear? It's been working OK for me.

[whpthomas]

I just did a check of my roll, unrolled 3m and took 5 samples 1.80, 1.76, 1.71. 1.73, 1.76 - this is not at all even, no wonder there are places where it stalls.

I would also caution about using olive oil, it may very well form a tacky film over time - hard to say - so could actually make things worse over time - although I don't think olive oil burns as 230c - I think the temperature needs to be a lot higher for that - but it still may dry out and leave a tacky deposit over time.

[Big Bonenfant]

Dont Use Olive Oil on filament !!! Just tried it worst ideal ever. Clogged everything up - I didnt think it would and was hoping it would help but now im try to get the machine to clear it all out. 

[Jose DeMille]

I have had so many problems with the clear PLA that I just tossed 2 rolls in the bin.  White has been working much better for me.

[whpthomas]

Big Bonenfant - I did say right from the start - you need your Replicator 2 dialled in first - its not a magic wand.

Firstly you need to check does your printer print reliably in any colour? Is the build plate level http://www.thingiverse.com/thing:39430, is the extruder plunger adjusted correctly or better upgraded your extruder http://www.thingiverse.com/thing:42250, is the packing density set correctly http://www.thingiverse.com/thing:39050, have you measured and entered your filament diameter - are you then printing clear PLA and still having problems? Do all that first and then tell me if it doesn't work.

[Ryan Gerrish]

I've been trying canola oil, and I've printed about 10 things in a row without fail. I'm not sure it's the oil, but I'm going to keep using it. That's with clear PLA from makerbot, as well as a couple other colors from Ultimachine. 

[Eric]

"I've been trying canola oil, and I've printed about 10 things in a row without fail. "

Thus far I have to agree with Ryan; the canola oil seems to be the secret additive. 

[David Mytchak]

Wayne,

I used a thermal imager to 'see' what temperature the extruder and nozzle were at.   Took the difference and added it to the 'base 230 C' settings.  Since my initial post, I found the temperature delta fluctuates *alot*.   But in short, I now run a tad hot (235-240), MK8 Extruder modification, and canola oil.    I haven't had a failed print since!  Oh and throw away the clear PLA - it's junk IMHO.

 

On Wednesday, January 16, 2013 7:56:21 PM UTC-6, Wayne Trattles wrote:

David,

Your story mirror our experience.  Got our Replicator 2 in December, however within a month we can't print anything.  We are going to attempt increasing the temperature and see how it impacts the build.

I see some other replies that indicate even small increments have a big impact. Did you experiment incrementally with increases in temperature or just straight to 242 degrees? 

Cheers... Wayne

[whpthomas]

While I agree the "clear PLA is junk" and I am extremely happy to have seen the end of it - I am also glad that something nice came of it after all the frustration. It now sits on my wife's desk at work - gets lots of compliments and envious looks - so helps to publicly justify my extravagant new toy to her and her work colleagues - quite a fitting end for my roll of MBI clear PLA *chirp*

[Dan Newman]

Looks nice, but was that a 17:13:00 build? What feed rate?

Dan

P.S. I just built a 1.3333 sized Cthulu at 140 mm/s on my Rep 2 as I'm exploring
vibration & z-wobble issues. Mind you, 140 mm/s is pushing it for the Mk8
extruder. I know that it definitely is for ABS on my ToM with a Mk7. And yes,
speeds regularly hit 140 mm/s whilst printing the shells. Grid rect. infill was
more around 125 mm/s according to the simulator.

[whpthomas]

I printed it at 95% scale

Infill 100%
Layer Height 0.15mm
Number of shells 1
Feedrate 80 mm/s
Travel Feedrate 150 mm/s
Print Temprature 230c

But I left the filament diameter at 1.70 so it was pushing out excess plastic - the rough surface texture actually made it look sparkly and hid the overhang imperfections quite nicely. Despite the back pressure from printing clear PLA at 1.70 instead of the 1.80 I usually do, the upgraded extruder didn't complain once.

[James Brigham]

Thanks so much for this info, like you I have been struggling to get a successful print using natural color PLA on my Replicator 2x.  After reading this I started increasing the temp of my extruder instead of decreasing it.  This has allowed me to finally get a successful print.  I had downloaded the 20mm test cube (http://www.thingiverse.com/thing:38108) and was attempting to print it.  The first 5 prints I was attempting, I kept decreasing the temp because the PLA would eventually jam (clicking sound), and would stop extruding near the beginning of the print, which made me think maybe it was too hot as implied by many other posts.  After reading this, I realized I could probably tell if it was too hot by immediately stopping the print as soon as I heard the clicking of it starting to jam, and then I immediately ran the utility to unload the PLA from the extruder.  Upon inspection of the PLA material I could clearly see it was not hardened or discolored so it couldn't be a too hot temp issue.  So after that I started increasing the temp, I assume the temp sensors are not reading the actual extruder temp properly, I have a temp gun on order now to verify that later.  So I started at 230 C - only about 1/16" printed before jam, then I ran a 240 C and only about 1/8" printed, then I ran it at 250 C and almost 1/2" printed.  It is also important to note, that I was having a lot of problems with printing ABS with the same machine, and the same nozzle.  I ran a ton of PLA through after the ABS, but now I am thinking it was a temp problem with the ABS as well, so I might switch back to that.  Maybe my failures will help someone else diagnose their issues as well.

My final successful settings:

infill: 15%

Number of shells: 3

Layer Height: .2

Temp: 255 C

Speed Extruding: 80

Speed Travel: 150

I don't have the Hood on my MakerBot yet because I don't have one.  Plate was not warmed for this, I used Blue Painters tape on the Build Plate.  I had also kinda used a trick to keep the nozzle from jamming in the very very beginning by exporting my file to the sd card for quick access.  Put the sd card in, unload your PLA filament cut off about 3 inches, Load your PLA filament but as soon as it grabs it, attempt to stop the process, the in the menu quickly print from SD card.. this reduces the time that filament is loaded in your nozzle compared the long delay of makerware slicing it then sending it to your makerbot.

On Monday, January 7, 2013 9:28:42 AM UTC-7, David Mytchak wrote:

I received my Rep2 in late October and had GREAT prints - worked freaking well.  Then came December 12th.  It went south and went south quickly.   I've had leaky extruders, MK8 Modification, 4 spools of PLA from different suppliers - you name it, I tried it.   I couldn't get a good print to save my life - like many of us on this forum.  It just wasn't working.  AirPrints in about 10 % of the build, etc.    I even replace my extruder out of my own pocket from the one from QU-BD (they sell a MBE replacement - looks like the same one MBI uses).  Anyway, prints that use to print were not even printing.  So yesterday, after reading posts from both Dan and whpthomas (both of which are great guys) and reading that both of them are PhD's, If two PhD's can't figure it out, I'm doomed. I was about to throw in the towel with Makerbot.   So I grabbed some coffee and sat thinking about returning my once loved Makerbot Replicator 2.  I was really bummed.   As I sat pouting with my coffee it hit me.  I've tried everything with degrading results and when I reverted back to the original extruder, I had the same, nozzle jams.  I read about lowering. the temperatures and have tried all temps from 190-230 all resulting in bad prints.    BAM- I'm assuming the temperature is accurate.  What if my 230 is really 190?  I doubt it but it was worth a try.  So I pull out my trusty Flir and sure enough - the Rep2 is reporting higher temperatures than actuals.  So I changed my geode to set the extruder temperature to 242 C and printed.   100% Success!  I've been dicking with this several weeks with 100% failure rate thinking it was everything from bad PLA to planetary alignment.   It looks like the heat sensor has lost its sensitivity over time.

[Joseph Chiu]

Just out of curiosity, when you switched to the QU-BD extruder, did you keep the original thermocouple and heater cartridge, or did you switch to the QU-BD set?

Joseph

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[Dan Newman]

On 17 May 2013 , at 3:09 PM, Joseph Chiu wrote:

> Just out of curiosity, when you switched to the QU-BD extruder, did you
> keep the original thermocouple and heater cartridge, or did you switch to
> the QU-BD set?

And the QU-BD set doesn't include a thermocouple. They only provide
a thermistor…. So you either have to use the old thermocouple OR hook
the thermistor to the MightyBoard's unused (for a Rep 2) HBP thermistor
input and then drive the extruder heater as though it's your build
platform.

Dan

[Paolo Fragola]

Guys, I paste the email I've just sent to Makerbot support, I hope it will help you guys, because, apparently, I solved my problems:

"Ciao Guys,

I wish the problem were just the filament, in fact, now the problem it's the filament, but for the last two months we've been through a nightmare.

The original extruder just doesn't work, so after tons of failures (read tons of filament wasted) we first replaced it with this alternative:Thing #42250, which works so much better then the original one, but I would say that this simply works, secondly, there's another design defect that doesn't allow the machine to work properly, and it's been very hard to debug.

Basically, the plastic pipe that leads the air from the fan to the object that is currently being printed, is connected to a big cable that brings the electricity to the stepper, fan and stuff.

When the extruder goes all the way right, this cable pull the plastic pipe, making all the piece of plastic tilted, blowing the air flow not on the print, but on the nozzle, cooling it! It lowers of course the nozzle temperature which doesn't melt the filament properly anymore.

The behavior just described becames a big deal when the object you wanna print is fairly wide, because the extruder will go from left to right and viceversa very often, and very quickly, making the nozzle temperature quite unstable, since the nozzle's electronic temperature control is not fast enough to compensate the dreadful temperature fluctuation.

I can't quantify, in terms of money, how much my company has lost, but it's quite a lot, since my rate is 400 pounds per day, and I've been debugging it for 3 weeks... and they bought this machine in order to save money.

Cheers,
Paolo."

In the end I've solved the problem using same tape to block the piece of plastic.

Ciao!

On Monday, January 7, 2013 4:28:42 PM UTC, David Mytchak wrote:

I received my Rep2 in late October and had GREAT prints - worked freaking well.  Then came December 12th.  It went south and went south quickly.   I've had leaky extruders, MK8 Modification, 4 spools of PLA from different suppliers - you name it, I tried it.   I couldn't get a good print to save my life - like many of us on this forum.  It just wasn't working.  AirPrints in about 10 % of the build, etc.    I even replace my extruder out of my own pocket from the one from QU-BD (they sell a MBE replacement - looks like the same one MBI uses).  Anyway, prints that use to print were not even printing.  So yesterday, after reading posts from both Dan and whpthomas (both of which are great guys) and reading that both of them are PhD's, If two PhD's can't figure it out, I'm doomed. I was about to throw in the towel with Makerbot.   So I grabbed some coffee and sat thinking about returning my once loved Makerbot Replicator 2.  I was really bummed.   As I sat pouting with my coffee it hit me.  I've tried everything with degrading results and when I reverted back to the original extruder, I had the same, nozzle jams.  I read about lowering the temperatures and have tried all temps from 190-230 all resulting in bad prints.    BAM- I'm assuming the temperature is accurate.  What if my 230 is really 190?  I doubt it but it was worth a try.  So I pull out my trusty Flir and sure enough - the Rep2 is reporting higher temperatures than actuals.  So I changed my geode to set the extruder temperature to 242 C and printed.   100% Success!  I've been dicking with this several weeks with 100% failure rate thinking it was everything from bad PLA to planetary alignment.   It looks like the heat sensor has lost its sensitivity over time.

[Iain Monteath]

Thanks to this thread i solved my rep 2 issues.

 

My builds started to failed halfway. After arround 100 hours of use.

 

Got the free upgraded the extruder from makerbot, no difference.

Check the shaft on the stepper and ground it back to stop gear slip, no difference.

Changed the temp up to 240, bang! worked like a charm.

 

Thanks!

 

[arkeon]

I had the same issue, even at 240 degree.

Just add a drop of oil on the filament when loading.

100% print success since I do that

[David Mytchak]

I've been gone for awhile.  I'm glad to see the post is helping others.  QU-BD did not include the thermocoupler.  MakerBot sent a new one.

[Dean Chiu]

I have basically tried everything on this clicking, clogging and air printing issue.

Oiling seems to be the only thing I have not tried, can anyone with such experience share how exactly to apply the oil?

Smear on the filament?

Drip it into the tiny heater entrance?  

What kind of oil? How much oil was applied? What type of oil? Canola oil?

Thanks,

David Mytchak於 2013年1月8日星期二UTC+8上午12時28分42秒寫道：

[Jay]

Dean,

Before you do that...can you give us some info to see if we can help? 

R2?

PLA - Mfg and color?

Temp - What are you trying?

Tramming - What are you using to set it? What's the gap?

Original Delrin Plunger? Or have you done the upgrade?

Tried other prints?

R2's can be frustrating but most of the problems have been discussed and solved on here. Depending on when your machine was manufactured, it may have 1 or more critical design faults to fix.

In my own case I had @3 months of stable and beautiful prints. Then I was getting clogs, knocking, and air prints. Seems like the filament suddenly got heat problems. I can print the opaque (black, white, silver) at 225*-230* all day long. The translucent filament is a PITA cause you have to hunt for the 'magic' temperature of the day. Once you get it you still have to husband the machine...as it seems like it will start knocking randomly...but unload/reload fixes it. 

There's a 'few' posts about this on here....

Jay