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UM 2 Nozzle Steam/Smoke

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Hi All

I'v been messing with an UM 2 and have been having some temperature related issues.

When I run the load swap filament script the extruder gets to a point where it starts sputtering steam/smoke. The PLA is clearly caramelizing and getting too hot.

It does the same thing at the beginning of a print and you can see the extrusion bubbling as it gets put onto the platform. Iv got the latest CURA and the latest firmware and at this point I'm not really sure where else to look?

One thing of note is that before I upgraded the firmware It seemed to work just fine however now I'm having this temperature problem.

Thanks in advanced for any help!

 

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Firstly, are you sure that you're printing with PLA?

Secondly, is your printer set to use PLA as the material? And what temps are preset for that?

As a starting point for diagnosing, I would unload the filament, and then do a factory reset (Maintenance -> Advanced -> Factory Reset)

It's possible that it could be absorbing some moisture and that could cause steaming etc, but it sounds more likely that the temperature readings are off somehow. Do you have any way to validate the temperature readings for the nozzle - e.g., using an external thermocouple thermometer?

 

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You may have bad wiring on the temp probe possibly. First of all check what temp the machine is attempting to go to like illuminarti says.

You can do some simple tests:

Set nozzle to 95C and put water on it and make sure it doesn't boil.

With machine at room temp, turn it on and check the nozzle temp. Make sure it is around 20C.

You can play with temp by turning on machine and going to MAINTENANCE ADVANCED and then "temperature" (or is it "nozzle temperature"?).

Please update your country location Rift. If you are in USA you can get much faster support in case you need a new temp probe. More likely the wire is loose underneath the machine (larger cover).

 

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Thanks for the replys!

Material Is definitely PLA =) The machine is also set to PLA as the material and its preset is 210C. I have done a few factory resets and even a few firmware uploads with no luck.

I haven't tried the water/nozzle test yet but unfortunately I don't have an external thermocouple to do testing with.

The PLA is definitely being overheated and there is some pressurization in the hotend because during the filament loading sequence at certain points it spits out PLA like a gasket just blew.

I'll check the wiring underneath to see if anything does not look correct. But other than that firmware wise everything should be set correctly and did seem to work properly at one point till I messed with firmware.

Location updated!

 

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I'm afraid you are going to damage your printer. I would not let it get hot enough to melt make "steam" until you get this fixed or figured out. There are parts in the print head that will be destroyed at 300C and the head can get up there no problem.

So do the boil test. You can find water somewhere and transport it on your finger if you don't have paper towels or q tips or drinking cups.

Another test. Go to CONFIGURATION ADVANCED MOVE MATERIAL. This will heat up to 220C. Spin the knob and watch the filament move up and down. move it up first to make sure it is moving. Then move it down slowly until it seems to stop. Then wait for the temp to hit 100C or so and move the material down some more. Pay attention to the temp and the tip of the nozzle and see where the filament starts leaking out. As soon as it does cut power (or just exit move material menu).

It should start leaking around 170C. 150C at the lowest I think. I haven't done this test myself but if you do the test and post your result I will try it also.

 

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Let me make something more clear - if the temp sensor is off by 100C then when the nozzle says it is at 50C it might actually be at 150C. And when you think it is at 210C it might actually be at 310C. That's why it is important to know if the sensor is working correctly. If the wires are extremely loose (barely making contact) it can easily have this much error.

 

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So I finally got to working on this again today, and have got some interesting results.

I did the water test. I created a custom material profile set the temperature to 95C and chose that profile and then went to the move material option.

First of all the temperature overshoots by almost 15C pretty much every time. I let the temperature stabilize at 95C and then dropped a water droplet on it. Sure enough it boiled up and evaporated.

What i have done now is basically keep increasing the temperature slowly till the PLA begins to flow nicely the way its supposed too. The number I have landed on is 150C.

Is it possible the motherboard is damaged or can this really only be the thermocouple? Iv never run into a bad thermocouple which is why this is really weird to me.

On a side note does anyone have the original firmware file that the machine might have shipped with. I would love to revert back and see if for some reason that would solve the problem just to completely rule out any sort of firmware glitch.

Thanks!

 

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So I found my problem. The thermocouple is totally loose. I can basically just pull it out. The worst part is that set screw that is supposed to clamp it in place is totally stripped.

I'm a bit confused with this part of the design. Are we really just relying on that one small set screw to push down on the thermal block enough to hold everything in place?

 

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